Green plants are called ‘autotrophs’, meaning that they feed themselves . (This is in contrast to all animals, which are ‘heterotrophs’ that gain nutrition by consuming other organisms.) These green plants feed themselves by photosynthesis, converting carbon dioxide and water into sugars (and oxygen). They also draw water and minerals from soils, and sometimes from water. So we are inclined to think of them as functionally independent entities, in terms of nutrition.
There are some salient exceptions to this simple plant-autotroph versus animal-heterotroph dichotomy. The carnivorous plants consume insects as a dietary supplement, so they are, in effect, both autotrophic and heterotrophic (see also http://Juneauempire.com/outdoors/2012-06-22/trails-carnivorous-plants). A few plants are not green at all and live a totally parasitic existence, drawing nutrition from host plants; they could be called heterotrophic too. For example, dwarf mistletoe that infects hemlocks and other conifers in our forests is not capable of much photosynthesis, and depends on its host tree for nutrition. Heavy infestations can kill the host tree. (However, the witches’ brooms that they create are useful to squirrels and birds). Northern ground cone, which is common near the Visitor Center at the glacier, is parasitic on the roots of alders (and a favorite food of local bears).
However, most of the other, supposedly autotrophic, plants actually live in association with other organisms that supply nutrients. Many species, including orchids and blueberries, associate with fungi that supply important minerals to the plant; these associations are called mycorrhizal (fungus-root) (see also http://Juneauempire.com/stories/010707/out_20070107004.shtml). Some species, such as alders and lupines, form root nodules that are inhabited by nitrogen-fixing bacteria that turn atmospheric nitrogen into a form usable by plants. Many trees form natural root grafts with their neighbors, drawing water and nutrition from each other (and sometimes diseases too).
Then there are the so-called hemi-parasitic plants, which I mentioned a couple of weeks ago in this space. They are green and can photosynthesize carbohydrates and live independently, but which also commonly parasitize other plants. They often grow better and set more seeds when they tap a host’s resources, but a host is not absolutely necessary. Their effect on host plants is generally negative, reducing growth and seed production. As far as I can determine (so far), we have three kinds of hemi-parasitic flowering plants in our flora.
Indian paintbrush (genus Castilleja; about twelve species in Alaska): They grow from sea level to the alpine zone. The colorful bracts of the inflorescences range in color from red to pink to yellow. Some are pollinated by hummingbirds, some by butterflies (especially Down South) and some are pollinated by bumblebees. Paintbrushes can accumulate selenium from soils and become toxic to humans and other vertebrates. They parasitize the roots of grasses, herbs, and some trees.
Yellow rattle (genus Rhinanthus; one species here): It is also known as rattlebox or rattlepod. The yellow flowers are bee-pollinated. When the petals drops off, after pollination, the remaining green calyx contains the loose (rattling) seeds. A root parasite mostly of grasses and legumes, it is known to decrease the productivity and survival of grasses. Therefore it is used in some regions to restore meadows and prairies where cultivated grasses have been grown; by decreasing the cover of grasses, there is more room for wild flowers and thus a diverse community of plants. And the helpful yellow rattle plants eventually get shaded out.
Louseworts (genus Pedicularis; about twenty species in Alaska): Louseworts have their unfortunate name because of an old, very silly, belief that they caused grazing cows to have lice. There are hundreds of species of lousewort in the world, with flower colors of all hues. Most are pollinated by bumblebees or other relatively large bees, but at least one is also pollinated by hummingbirds. Only some have nectar in the flowers. Louseworts are root parasites, often of members of the heath family, such as blueberries.
The bottom line of all this is that green, flowering plants are not such independent entities as one might think. Many, if not most, of them interact with other plants, fungi, or bacteria to supplement their nutrition. Our forests and meadows would be impoverished without these interactions.
Fall came early this year—the August rains seemed endless. I returned from a short hike almost as wet as I’ve even been (barring a swim or a nice hot shower). The creeks and rivers were ‘on a tear’, roaring along full of sediment, branches, and logs. Flattened grasses showed where the water had recently been even higher.
On the way home, I stopped at the grocery store. When I checked out with my purchases, a young gal offered to carry out my bags. I said “You don’t really want to go out in THAT!” She said, with a smile, “We live in Juneau,” as she picked up my bags. Good on ya, gal! (But I did carry my own bags out to the car, after all.)
An interesting, but sad, finding in the middle of the trail one day was a dead mouse. Not any old mouse, mind you. This one had a very long, bicolored tail, unusually large hind feet, huge ears, and magnificent whiskers. I thought it was a young jumping mouse, which I’ve never seen alive around here, although they are known to occur in Southeast. It was very thin and may have starved or drowned when its habitat got flooded. (However, the Museum experts said I was wrong—it was just a Keen’s deer mouse. Sigh. But I’ll tell you about jumping mice anyway!)
There are two species of jumping mouse in Southeast, but they are difficult to distinguish. Typically, they live in meadows, wet shrubby areas, and near marshes, and they eat bugs, fungi, and seeds. In summer, they build globular nests on the surface of the ground in tall grass or near small shrubs. They are said to be active only about three months of the year. They hibernate for about nine months, but reportedly many of them, especially the smaller individuals, die before the next summer if they don’t put on enough fat to last through the long winter months.
Near our backyard glacier, bears were actively foraging on sockeye, strewing partially eaten carcasses over the landscape. A yearling fled up a cottonwood when a big bruiser of a bruin approached; the youngster hissed and huffed from its refuge, but soon settled down for a nap.
On the ground near the viewing platform were many carcasses in various states of decay. One had been host to a teeming mass of fly maggots two days earlier, but now it lay limp and mostly decomposed. The maggots were dispersing into the surrounding mats of grass and moss (packed down by bear feet), presumably in search of pupation sites, where they could transform themselves into flies.
Many of the maggots never made it. A juvenile robin appeared and nabbed them one by one, working over several square yards of matted vegetation. The robin foraged repeatedly over the same area, getting more maggots with each pass. She captured several dozen juicy little bits of fat and protein in just a few minutes. A sibling joined her and foraged in the same area, but the first bird had the best pickings.
Photo by Bob Armstrong
Two juvenile Lincoln’s sparrows were maggot-hunting near another rotting sockeye, with much less success than the robins. Other small creatures come to capitalize on the fishy bonanza—juvenile hermit thrushes, a young varied thrush, a pine siskin, mallards, voles, and shrews. Nothing gets wasted, even in the absence of eagles, gulls, ravens, and crows, which scavenge carcasses on lower stream reaches. The surviving maggots make more flies, which nourish next year’s barn swallows (which nest nearby), warblers, and occasional flycatchers. Anything left gets leached into the soil, to fertilize the vegetation and, eventually, the stream. Research, both here in Juneau and in British Columbia, has shown that more birds nest near salmon streams than near streams that lack salmon runs, suggesting that the vegetation is more lush or that insect prey is more abundant around salmon streams. It could be said that salmon fuel the natural economy of Southeast.
One day in late March, I wandered toward the Mendenhall Glacier in search of mountain goats. March is often a good time to see them near Nugget Falls or across the lake on the big rock peninsula at the foot of Mt. McGinnis. Or even on the lake itself! In winter, mountain goats leave their summer range in the alpine and venture down into the forested zones, where they can find some food, albeit sometimes of poor quality, under the trees.
I had previously tried several times to find them near the glacier but I had been ‘skunked.’ And I was beginning to think that perhaps the rangers at the Visitor Center had locked up the goats somewhere (along with the beavers that are never visible in the beaver cam when I look for them).
Finally, on this day, I got lucky. There, just beyond Nugget Falls, was the elusive white beast. But wait—this one had eight legs! It was a nanny, with a nearly year-old kid walking right next to its mom, but on the far side of her, so I could only detect its presence by those supernumerary legs. I was too far away to tell if the nanny was pregnant with this year’s kid, which would be born later in the spring.
Female mountain goats in Southeast don’t reproduce until they are four or five years old, according to ADFG research. Then, if conditions are good, they may produce a kid every year for several years; if conditions are poor, they may skip a year. However, the probability of survival in Southeast decreases steadily after age four or five, and drops rather quickly after age eight or so.
Photo by Jos Bakker
Snow can create big problems for mountain goats, especially as they get older. Deep snow makes much of their plant food inaccessible and also makes travel energetically expensive, unless the snow is well compacted and can support their weight. Fresh snow on unconsolidated snow pack can lead to avalanches, a significant source of death for goats. I once found an entire skeleton of a fairly young goat (its teeth were not very worn) at the base of a long avalanche chute. In general, mountain goat survival in Southeast decreases as snowfall increases. Late winter and early spring are seasons of lowest survival, when the cumulative effects of winter difficulties take effect. Old animals and males are the hardest hit.
You might think that summer is totally benign, in terms of weather. But mountain goats can’t handle really warm weather. When temperatures rise, they tend to seek north-facing slopes, or shady spots behind rocks, or higher elevations, or at least a nice cool snow pack for resting. Average temperatures greater than about 48 degrees F in July and August are ‘hot’ even for young goats. The average temperature is correlated with the number of days that reached over 60 degrees F. Older goats may suffer heat stress at even lower temperatures. Recent ADFG research in Southeast suggests that warm summers are often followed by increased winter mortality, especially for older goats.
Why should warm summers create difficulties? One possibility is that high summer temperatures melt the snow rapidly, so that the ground vegetation all matures in a relatively short time. In contrast, a cool summer would melt back the snow pack more gradually, so that the emerging vegetation is exposed over a longer period of time. Some evidence suggests that young, emerging plants have higher nutritional value than mature ones. Then cool summers would offer high quality forage over a longer period of time than warm summers. Furthermore, higher temperatures may more directly cause lowered forage quality because the plants grow faster and contain more indigestible fiber. Cool summers also reduce heat stress and may allow goats to forage more efficiently and perhaps more often (if they don’t have to seek shade as frequently). Thus, cool summers might allow goats to go into winter in better condition than after warm summers.
Mountain goats, like some other alpine specialists, tend to develop localized populations that are genetically different from each other. For example, ADFG research has documented distinct goat populations east and west of Berners Bay, and north and south of the Katzehin River, with little movement of animals between populations. Relative isolation of populations often allows the development of local adaptations specific to each population, if environmental and demographic conditions are different, but it remains to be seen to what extent this is true for mountain goats.
Detailed genetic analyses by Canadian researchers has shown that mountain goats probably survived the last major glaciation in at least two refugia. Fossil evidence had previously supported the idea of a southern refugium, perhaps in southern British Columbia or thereabouts. But the more recent molecular data show that another refugium probably existed in northern BC or Southeast Alaska; goats from northern areas tend to be different genetically from those of the southern areas. In the thousands of years since the Pleistocene glacier began to recede, some movement of goats must have occurred, because some populations now consist of both northern and southern genetic types. Similar historical differentiation of northern and southern population is known for other mammals as well, including ermine, red fox, and mountain sheep.
I have walked the rainforest trail on North Douglas I-don’t-know-how-many times, but every time there is something worth noticing—including some things that I’ve missed or just didn’t think about on past walks there. In mid January a friend and I strolled that trail again, just to see what we could see. It was a productive stroll! Here are some of the things of interest.
The hemlocks in that area commonly have ‘fluted’ trunks, with pronounced, rounded ridges running up from the base. This ropy-looking growth feature (no relation to the musical instruments!) is common in Southeast Alaska but less common farther south, for reasons unknown. The fluting apparently results when lateral transfer of nutrients is restricted, so some parts of the trunk get more nourishment than others and therefore grow better. Several factors, such as root or branch damage, have been shown to have temporary effects on lateral transfer of nutrients, but damaged trees can overcome the effects as they continue to grow. One study reported that trees exposed to mechanical bending by the wind are more likely to develop flutes than trees not subject to much bending; thus, trees on windy coasts or unstable substrates are more likely to develop flutes than inland trees. An experiment that stabilized the trunks of young hemlocks by running guy lines out to nearby trees showed that stabilization reduced flute development (as judged by growth rings) only in some years. So other, still unknown, factors must be involved as well.
The red alder trunks near the trail often bear belts of dark, rough bark with short vertical fissures. Some belts are only a few inches wide but others may be a foot or more in width. According to the forest pathologists (Paul Hennon and Robin Mulvey) at the Forestry Sciences Lab, these areas have been infected by the so-called rough-bark fungus that does not damage the wood but rather affects only the bark layers. Young alders are particularly susceptible to infection, but the rough bark remains as the tree ages. Scanning several trunks, I thought I could detect newer infections, just beginning to develop, that had bands of small vertical fissures round the trunk, without the dark color. Although this fungus seems to be common along this trail, a search for it in the Amalga Harbor area failed to find it, so the distribution appears to be localized.
We noticed that some of the rough-bark belts had several old, oval divots in the bark, above or below the belt. The divots bear a resemblance to the sap wells made by sapsuckers and we wondered if the birds had sampled these trees in the earlier stages of the infection. Or could the birds have helped to disperse the fungus by drilling wells, some of which are now covered by the rough bark?
Many of the hemlocks out here have rows of deep conical pits around the trunk (not at all like sapsucker wells). In addition, lots of the trunks have had the outermost layer of bark flaked off, exposing paler bark layers below. All of this is evidence of woodpecker activity—in search of bugs living in the bark crevices or burrowing under the thick bark. Some of the activity was quite recent, because flakes of outer bark lay on top of the snow. Who dunnit?? Not sapsuckers, because they are gone for the winter. Maybe three-toed or black-backed woodpeckers. Neither is common in our region—in fact, except for sapsuckers, woodpeckers are strangely uncommon in our forests. But why? One speculation is that local predators such as goshawks keep woodpecker populations down.
We found at least two vertical scars on older trees; the scars had been made a long time ago, because the trees had grown healing tissues over the edges, reducing the openings to narrow slits. Both scars were about four feet long and very similar to each other, located about eye level. Inside the slit we could see the flat, gray wood. We wondered if these scars could have had an anthropogenic origin and, if so, then what was the reason for people to make them. Or perhaps an adjacent tree had fallen along the trunk, stripping off the bark—a fairly common occurrence, but these scars were so similar to each other that this seemed unlikely. There’s more to be learned…
This walk was not just about trees, however. Large flocks of pine siskins swooped over the canopy. A mixed flock of golden-crowned kinglets and chickadees foraged on the beach fringe, talking all the while. A lone horned grebe in winter plumage dove in the bay, ignoring the mallards that nibbled at the water’s edge and the goldeneyes loafing near the point. Most interesting to me was a chance observation: I happened to turn around in a lucky spot and something caught my eye. A tuft of moss and grass stuck out of a niche in a tree trunk, so I went over to check it out. ‘Twas a bird nest—but maybe not just one! There were three layers piled one atop the other, as if three nests had been built here (I did not tear the structure apart to be sure). Perhaps some small bird had really liked this spot. Birds don’t usually renest in a site where their previous nest failed, so (if this was the same individual), she had been successful here before. Who was it? Possibly a junco…
I tried to second-guess Juneau weather the other day. The Parks and Rec hike was scheduled for Mt Roberts, up to the tram and the cross. I figured that trail would be a nightmare of ice, so I (with a friend) opted to go out the road—where it is usually colder, they say. So we hoped that the rain-and-snow mix that was falling in town would be just nice falling snow in the colder zone out the road. Ha!
Wrong! Out the road it was raining. The temperature was several degrees warmer than in town. And there was even less snow on the ground out there. It doesn’t pay to try to second-guess our weather!
Nevertheless, there we were—way out the road. So we went up the Bessie Creek trail, which starts just past Adlersheim. The quagmires that mess up the beginning of the trail were largely frozen and elicited none of the usual bad words from us. The route through the forest was quite passable: some snow, a little ice, and some open ground. Cleats were useful but not absolutely necessary.
I think Bessie meadows are at an elevation of about six hundred feet. Alas, the new-snow line was tantalizingly just out of reach, about a hundred feet or so higher. However, the existing snow was plenty deep for good snowshoeing.
We put on our snowshoes when we reached the beaver pond and the main meadow and then we strolled around the beautiful, rolling meadow in the rain. Someday I’d like to do the whole route from the Bessie meadows down along the south fork of Cowee Creek to the mainstem of Cowee Creek, and thence back to the road.
Early morning snow and all-day rain had blurred most of the animal tracks, unfortunately. A series of paired, rounded paw prints, with about four or five feet between pairs, suggested a large sort of weasel-relative. Some other creature had plunged deeply in the snow, lunging forward, but I couldn’t be sure who it had been.
We found a horde of pine siskins on the ground at the edge of the forest. They were busily picking up fallen seeds and chattering to each other. There could easily have been a thousand of them. Our approach sent them flying, but they returned to the feast as soon as we went by.
I heard a gang of red crossbills, foraging in the treetops. I’d never really understood how the crossed bill-tips served to pry open cones. But a good video is available online from the Cornell University Laboratory of Ornithology; this makes it all very clear. Once the cone scale is pried up by the crossed bills, the bird extracts a seed and removes the wing by holding the seed in a palatal groove while the tongue helps work the wing off the seed.
These crossed bills are somehow also capable of picking up seeds and grit from the ground, just as do birds with ordinary, straight bills.
Red crossbills are widespread in North America, and may comprise a group of closely related species. Different types of crossbill are adapted to forage specifically on certain species of conifer cones; some have large bills and large palatal grooves for large cones with large seeds, and others have small bills and small palatal grooves for small seeds. Each type of crossbill can also feed on other species of conifer, but they are most efficient on their own type of cone. Their calls are also distinctive, to the trained ear, and they seldom seem to interbreed. Red crossbills, and the related white-winged crossbill, move around seasonally, appearing in large numbers in a certain place and then moving on in search of better foraging.
After several hours of soggily tramping around, we got back to the car, wet but happy. And the Mt Roberts hikers? Well, it seems I was not far wrong in thinking that trail was a misery.
porcupine sign, hemlock observations, and singing birds
For weeks I’d been wanting to explore the Lemon Creek Trail, in hopes of enticing Parks and Rec hikers to go there again, after a hiatus of several years. I know the first part of the trail well—up over the saddle behind Home Depot, from many excursions to a dipper nest site that’s approachable from upstream (after a short bushwhack from trail to creek). But just over the saddle is a small swampy area and another small creek, and the continuation of the trail on the far side of the swamp eluded me.
So, one day in late March, I headed up the Lemon Creek trail with two friends, one with two feet and one with four feet. The trail was pretty icy, and we met a guy who had turned back, but our ice cleats proved themselves once more. Near the swamp, we crossed the little creek on a snow bridge, but –of course—missed the spot where the trail resumed.
So we floundered on down to some alder thickets close to Lemon Creek where the snow was still pretty deep. Soon we noticed a series of elderberry stems that had been nipped off. Sometimes the nipped-off stem was still there, and then we saw that the leaf buds had been nibbled away. Aha! So that’s what the porcupines were after. Cut off the whole stem to get a few bits of budding leaf. Most of the elderberry bushes in this area had been pruned by foraging porcupines. I have to wonder why they like the stuff—it smells bad (to me). I think elderberry has defensive chemicals intended to deter munchers, but porcupines seem to be able to deal with them, or else they are desperately hungry.
After plunging through the snow for a little while longer, I said that I had a faint memory that the trail should be a bit up the slope in the conifers. So we peered up the steep hillside, well decorated with devils club and, indeed, it looked like a trail up there. Up we scrambled, and there it was. Now I knew we could follow it back and find where it connected to the little swamp. It was a decent day, with just a little misty rain from time to time, so, having regained the trail, we went on. And the rest was ‘cake’. The trail is clear and easy to follow, probably because the research teams that go up to the glacier have kept it open.
Along the way, we commented that porcupines seldom seem to completely girdle the hemlock trees from which they eat bark; usually they just sample a patch on one side. No sooner had we said this than we came upon a twenty-foot hemlock that was completely de-barked all the way around from about one foot high to about fifteen feet above the ground. What made that little hemlock so tasty, apparently? It was outcompeted (for light) by its much taller neighbors, so maybe it didn’t have a lot of energy to allocate to defensive chemicals.
We trudged and slid along, eventually dropping back down to a broad sand flat with lots of alders and the remnants of an old log bridge. Just upstream from here, the creek makes a ninety-degree turn, and so does the trail, which goes on up the valley.
Several years ago, Parks and Rec used to be able to walk up the road through the gravel pit on the opposite side of Lemon Creek, cross a bridge, and thus get to the wooded valley that comes down from the glacier. But nowadays, one gets to this point by almost two miles of trail from the trailhead behind Home Depot. After numerous side excursions to look at things, by the time we reached the sharp angle in the stream, it was time to turn around. So we perched on a log to share a snack while gazing at the creek and wistfully contemplating another day when that upper valley could be explored.
Our return trip was uneventful, although the snow bridge that held both of us on the outward-bound trip only held one of us on the way back. But at least I didn’t get my feet wet in the little creek!
The conifers were full of talkative pine siskins and a few crossbills. Juncos flirted around in the brush by the big sand flat. Varied thrushes sang all day. Kingfishers rattled up and down the stream, no doubt checking out cutbanks in which to dig a nest hole. A dipper put on a concert down in the creek. Best of all, we heard our first winter wrens trilling enthusiastically. But technically, we can’t call them winter wrens any more. The taxonomists have decided that the western winter wrens are genetically distinct from winter wrens in the east (and Europe, where they are called The Wren). Although the plumage differences are subtle, and the songs are not very different, the calls are reported to be distinctive. So now our wrens are known as Pacific wrens.
All in all, a good day. Mission accomplished, most pleasantly. Now to see if Parks and Rec will try this trail, come summer.
I don’t get to go whale-watching very often, but when I do, I usually see something interesting and new questions frequently get stirred up.
One trip gave us a good view of humpback whales doing their locally famous bubble-net feeding. Most of us here have seen this behavior at one time or another, but somehow it has not become ‘old hat’. How does a group of whales decide which one will create the rising, circular curtain of bubbles that rings a school of little fish? How did they invent this foraging tactic in the first place? Did it really originate here, and get carried to Prince William Sound whales by a wandering Juneau whale? How do they coordinate the upward rush of several whales through the panicking fish and avoid crashing into each other?
Another trip brought a troop of Dall’s porpoises, cavorting around the bow of the ship. The group grew, as additional individuals came zooming in from who knows where. They played there for some time, to the great delight of all on board. Then they disappeared, apparently on some magical signal; suddenly they were simply gone, vanished out of sight. Why did they all gather by our ship? And why did they go?
Then, in early September, we watched a small pod of orcas cruise by Little Island, where hundreds of Steller’s sea lions, of all sizes, had hauled out. Even the few sea lions that happened to be in the water a few feet from their dry confreres on the beach did not seem to be alarmed at the orcas passing nearby. Mammal-eating orcas don’t use their sonar to find prey, because mammals can hear the beeps. So we thought that these must be a resident, fish-eating bunch of orcas, using their sonar to find fish and therefore no threat to the sea lions.
As the orcas went on down along Ralston Island, we learned that this was actually a group of transient, mammal-eating predators, identified by a known mark on one of them. Nevertheless, no prey was visible and they acted (to our eyes) as if they were hunting fish: sudden, brief changes of direction and quick dives. This led to the question of whether mammal-eating orcas might sometimes snack on fish as well.
Then a small band of juvenile sea lions came into view from the opposite direction, seemingly oblivious of the jinking-around orcas—until the two groups of animals were very close. Then the sea lions really freaked out, caught between the rocky shore and the orcas. Much frantic splashing and churning about! As the orcas placidly went on their way, the sea lions calmed down and swam toward Little Island. What was going on here? Mammal-eating, transient orcas with already full stomachs? Just fun and games for the orcas? Mistaken identification by the sea lions?
Later that same afternoon, we encountered a scattered group of humpbacks doing nothing very exciting. But alongside our boat there appeared a solitary sea lion with something in its teeth. That sizable something was tossed and thrashed about until it was just a rag (and a few loose bits for the attending gulls). Finally we got a closer look and saw tentacles with sucker discs, just before the whole thing disappeared down the gullet of the sea lion. The octopus was caught at depth of over four hundred feet, not a very deep dive for a sea lion.
Humans have been fascinated by orchids for ages. When we think about orchids, most of us visualize the flamboyant, exuberant, gaudy floral displays produced chiefly by tropical species or by the activities of avid orchid breeders. Fair enough, but…
All that flamboyance and showiness evolved because each kind of orchid flower is very complex and adapted to particular pollinators. Most of the pollinators are insects, but a few are pollinated by hummingbirds. Each kind of flower is visited, typically, in a very specific way by its pollinating animals. Although some orchids do not require a pollinator but, rather, simply pollinate themselves, the majority set seed after the visit of a pollinating animal. Different kinds of orchids offer different rewards to pollinators, usually nectar, but sometimes special oils or fragrances. Some reward-less orchids rely on fooling visitors, by just looking like they might have a reward and so attracting naïve insects, or (most famously) by looking like a female insect and fooling the male insects into trying to copulate with the flower.
Orchids have actually gone a bit crazy. There are probably over twenty-five thousand species; taxonomists are not sure just how many there are. But there are way more orchids than all the birds and mammals in the whole world, and more orchids than any other kind of flowering plant except perhaps the aster and daisy family. Although they are most common in the tropics, orchids can be found almost everywhere except Antarctica and the very High Arctic, occupying almost any habitat, including on other plants; one even lives entirely underground.
Southeast Alaska has its share of orchids: as near as I can tell, we have about twenty-six species in nine or ten genera (genera is the plural of genus, a taxonomic unit that clusters similar species together). The numbers are a bit uncertain because taxonomists often have differing opinions on how to demarcate the species and how to cluster them. In this space, I intend to introduce each genus that’s found in Southeast, with a bit of information about its name and its biology. Most of our orchids are not as gaudy as their southern relatives, but they share some nifty adaptations with their gaudier cousins. Because I like to know how things work, I’m including information on how the flowers function, that is, how they control the visits of their pollinators—which, after all, is what orchids are famous for!.
Before I launch a discussion of our orchids, it is useful to explain a few things that apply to all or most orchids. By doing so, repetition can be avoided or at least reduced. And, by the way, in case you were wondering, the name ‘orchid’ comes from the Greek word for testicle, because the bulbous roots of some species reminded someone of male gonads.
All orchids produce huge numbers of minute, dust-like seeds that lack stored nutrients for seedling germination and growth. Therefore all seeds depend on forming associations with particular fungi (mycorrhizae) that bring in nutrients from decaying organic matter or from other plants. Finding the right mycorrhiza is a chancy business, and most seeds just die. If a seed finds the right mycorrhiza and germinates, most orchids plants eventually produce green leaves that can photosynthesize carbohydrates, and thus they can live somewhat independently. But some orchids have no greenery and are forever dependent on their mycorrhizae.
I will spare you (and me!) the fine details of the intricate arrangements of orchid flowers, which can be bewilderingly complex. But I will mention one very peculiar and mysterious thing: while an orchid flower is developing, it often (for some odd reason) rotates a hundred and eighty degrees on its axis, so what was up is now down. That is rather mysterious in itself. In one species of the genus Malaxis (at least in the European populations of a species that we have in our area), however, the rotation is a full three hundred and sixty degrees, so what was up is again up. I find this most peculiar—if the goal is to have ‘up’ be ‘up’, why rotate at all? Darwin noted this, and then, to confound all logic, saw that the ripe seed pod UNtwisted itself by three hundred and sixty degrees. Very peculiar. And all of that begs the question: Do those that twist only a hundred and eighty degrees also untwist when seed ripen?? It is all very strange!
Most orchids disperse pollen in clumps, rather than as loose collections of powdery, separated pollen grains (as in most flowers). The clumps of pollen grains are generally held together by sticky material and elastic threads, and sometimes several clumps are stuck together. The clumps are called pollinia. Although some other flowering plants (such as milkweeds) produce pollinia too, this habit is relatively unusual. When they pick up a pollinium, pollinators then carry many pollen grains at a time. This would seem to be very efficient, but actually the seed production of many orchids is limited by too-few pollinator visits.
OK, now for our Southeast orchids. I’ll start with the smallest and least conspicuous, dealing with each genus in turn, working up to some local beauties.
Listera. The genus is named for a seventeenth century English naturalist (Listera). These diminutive plants are known as twayblades, for the two broad leaves flanking the stem. There are four species in southeast, although two are rare. I have seen good numbers of two species along the rainforest trail near Bartlett Cove, and they should be quite widespread elsewhere in Southeast.
The nectar-bearing flowers are tiny, only a few millimeters across, and they are pollinated by equally miniscule insects such as dance flies, fungus gnats, or minute wasps. Darwin thoroughly studied the pollination mechanism of an English species of Listera, and ours apparently work the same way. When an insect touches a beak-like structure in the flower, a drop of very sticky liquid explodes from that structure, catching the tips of the pollinia and gumming them to the head (often the eyes) of the visiting insect. The sticky fluid hardens almost immediately, so the insect flies away with pollinia stuck on its head. After firing the sticky liquid and the pollinia, the female receptive surface (called a stigma) is exposed and ready to receive a pollinium from the next insect. When an insect bearing a pollinium on its head visits a flower whose stigma is exposed, the pollinium contacts the sticky stigma, so pollen is pulled away from the insect and pollination occurs. For all of this to happen, the beak-like structure actually moves, first to put the pollinia in position to be picked up by the exploding drop, and then to expose the stigma so another insect can deposit pollen.
frog orchid. Photo by Bob Armstrong
Coeloglossum. The genus name means ‘hollow tongue’; I have not learned the source of this name; one idea was that it derived from the spur that holds nectar, but since this is shaped like a tiny sac and is not at all tongue-like, this name is puzzling. The common name is frog orchid, but it doesn’t look like a frog (to me), so that name is also a puzzle. This is reportedly a short-lived species, able to flower during its first year above ground and seldom living more than about three years. The flowers can be pollinated by small insects of various sorts, but details of how the flower works are not available; self-pollination is possible.
I’ve seen frog orchids on Gold Ridge, where they are not common. Although they can apparently produce many greenish flowers on each stem, the ones I’ve seen have all had only a few flowers on each short stem. These plants on Gold Ridge are at risk by being trampled by the many visitors that walk above the tram.
Malaxis. Once known as Hammarbya, the newer name of Malaxis comes from a Greek word meaning soft or softening, referring to the soft leaves of some species. The common name is, sadly, adder’s mouth orchid or adder’s tongue. Someone must have thought the flower resembled the front end of a poisonous snake (it takes a very unusual imagination!). There are two species in Southeast, mostly in bogs.
The tiny (less than two millimeters) flowers are yellowish green. They have nectar and a sweet odor, which attract very small insects, such a fungus gnats. Darwin studied one of our species, which also occurs in Eurasia. He observed that a sticky drop holds the ends of the pollinia, and when an insect enters the narrow opening of the flower, it runs into that sticky drop and pulls out the pollinia (on lower, front part of its thorax) when it flies on. When the insect then enters the next narrow flower, the pollinia are pulled off, in contact with the stigma. Apparently this species does not self-pollinate but requires an insect to bring pollen from another plant of the same species, achieving cross-pollination; however, the second species in our area may often self-pollinate.
Malaxis orchids reportedly have the peculiar but useful habit of vegetative propagation by means of little bud-like structures on the leaf tips; these little structures can sprout and grow into new plants.
Dance fly in a coralroot orchid blossom. Photo by Bob Armstrong
Corallorhiza. There are two species of these coral-root orchids in Southeast. Both names describe the appearance of the roots, which are thought to look like branching corals. Both species produce fairly tall flowering stems with multiple flowers, either pink or yellow. Both lack any green pigment, so they cannot produce their own carbohydrates and are therefore dependent on their mycorrhizal associates for nutrients.
Both species are visited by small insects, including flies and wasps and bees, that can carry some pollen from plant to plant. However, most seeds are apparently produced by self-pollination, without a visit from an insect bringing pollen from another plant.
The pink-flowered species is often seen in conifer forest, but the yellow-flowered one seems to prefer more open, often deciduous woods.
Goodyera. The genus bears the name of a seventeenth –century botanist. The common name is entirely ridiculous; it is called rattlesnake plantain, although it has nothing to do with snakes of any kind nor is it a plantain. Because the leaves are sometimes mottled with white, some early pioneers may have been reminded of snakeskin and thought, by simple association, it could be used to treat snakebite. However, there aren’t many rattlers where our species lives, so the name seems doubly foolish.
One species of Goodyera grows in our forests. The flowers are white, borne on a tall spike. Each flower is first male, with mature pollen, and then female, with a sticky, receptive stigma (this sequence is called protandry, or first-male). Internal parts of the flower rearrange themselves slightly to better expose the stigma after pollen is removed. Pollination is reported to be accomplished by bumblebees, which first visit the older, female-phase flowers low on the spike, depositing any pollinia they may carry. Then the bees move up the spike, reaching the male-phase flowers and picking up pollinia, on their heads or tongues, to carry on to the next plant. Thus, seeds are typically produced by cross-pollination between different plants.
Platanthera. Photo by Pam Bergeson
Platanthera. There are at least eight species in Southeast. Some produce white, very aromatic flowers, while others make greenish flowers, but all bear the flowers on an elongated stalk. These orchids formerly were classified as species of Habenaria, from the Latin word for strap or rein (probably because one of the main flower parts is flat), hence the common name of rein orchid; an alternative name is bog orchid (although some also grow in wet forests). The current genus name seems to mean ‘flat flower’, perhaps referring to the same flower part.
Bog orchids are pollinated by a variety of insects, some mostly by moths or both moths and butterflies, others probably by bees, some by small flies and mosquitoes, and some by almost any insect of the right size and inclination. Our white, aromatic bog orchid is pollinated primarily by moths, at night, and our green bog orchid may have several possible pollinators. Certain species exhibit regional variation in the length of the nectar spur, odor of the flower, and the type of insect pollinators, even within the same species.
Platantheras present nectar in a nectar spur, which is visited by a foraging and pollinating insect, when it enters the flower in the proper way, from the front, and encounters the sexual parts. But at least some species also produce small dollops of nectar on other parts of the flower, perhaps to increase the allure of the flower to insects that subsequently enter the flower in the proper way.
The pollination mechanism is simple: the insect shoves it head into the flower, reaching into the nectar spur, and bumps into the sticky parts of the pollinia, which then attach to the eyes or tongue of the insect. Although cross-pollination is usually the norm, many of them may simply self-pollinate, if no pollinator visits them.
Piperia. Named for an American botanist, two species occur here; they are widespread but rare. They are similar to and sometimes classified with Platanthera, but sometimes they are classified in their own genus. They typically live in open woods. The flowering stem bears a number of small, green or white flowers that are reported to be aromatic especially at night, when they are pollinated by moths. A visiting moth can poke its head and tongue a short distance into the flower, and pick up pollinia on the tongue; an older flower is more open, and a visiting moth bearing pollinia can insert its head far enough to deposit pollinia on the stigma. Piperias are thought to be chiefly cross-pollinated.
Spiranthes. As the name suggests, the flowers spiral up in a tall spike. The common name is ladies’ tresses, because someone thought the inflorescence looks a bit like a woman’s braids. The white flowers are pollinated principally by long-tongued bumblebees. As in Goodyera, the flowers are typically protandrous (first male, then female), and when nectar-foraging bees work their way up the spike, from older flowers to younger ones, the last flowers they visit stick pollinia onto the bees’ tongues. As observed in detail by Darwin on a similar species, the pollinia are attached to a sticky disc, whose stickiness is activated by the bee’s tongue as it passes through the narrow opening to the pool of nectar. When the bee’s tongue is withdrawn, the pollinia are pulled out. On older flowers, the internal parts of the flower have been rearranged slightly, widening the opening where the bee inserts its head and exposing the receptive stigma. Flowers are usually out-crossed, but when there are few pollinator visits, male and female phases of each flower may overlap more, and some self-pollination may occur if a bee does visit. There is one species in Southeast. A study of our species on Vancouver Island, B. C. found that flowers received abundant bee visits and set seed accordingly, but visitation rates and seed production have not been studied here, where bee populations may be less dense.
Sparrow’s-egg orchid. Photo by Kerry Howard
Cypripedium. The genus name of ladyslippers or moccasin flowers comes from classical mythology. It refers to the foot of Aphrodite (or Venus), who was formerly called Kypris. Presumably an inventive observer imagined that the foot of a goddess of love might wear a floral slipper. We have at least one species (with white flowers), mostly in open woods in scattered locations, and two others may creep in to the northernmost part of Southeast.
Ladyslippers have no nectar, but they are often aromatic. The flower acts like a trap. When a small bee enters the pouch-like slipper, it cannot get out the same way because of the slippery sides and in-rolled margin of the pouch. So the bee has to exit through the upper part of the flower and, in so doing, it passes by the sexual parts of the flower. In general, Cypripedium pollen is very sticky and readily adheres to the crawling bee, which picks up pollen as it leaves the flower. When the bee enters and exits another ladyslipper, it encounters the female parts first, brushing off pollen on the stigma.
Some species of ladyslippers can become dormant for as long as three to five years, not showing above-ground shoots at all during that time. Prolonged dormancy can be induced by stress, perhaps from a bad growing season or the cost of making many seeds. These dormancy periods sometimes presage mortality, but in other cases, the shoots come up again and the flower blooms after its rest period.
Calypso. Photo by Bob Armstrong
Calypso. The common name of fairyslipper was no doubt inspired by its delicate and lovely shape, suitable perhaps for an ethereal, light-footed creature. The genus name comes ultimately from the Greek word for concealed and more immediately from the mythological goddess, Calypso. She was a beautiful nymph that lived in the forest. According to Homer’s Odyssey, she found Ulysses (Odysseus) when he was shipwrecked on her island, and she kept him for seven years.
The showy, pink-purple flower, usually one per stem, is said to be very aromatic, but it has no nectar. Bumblebee queens are the principal pollinators. Naïve queens (with no previous experience with this flower) visit calypsos but each queen soon learns that there are no nectar rewards to be found there, although the aroma might suggest otherwise. Such pollination by deception is characteristic of many orchids. Supposedly the queen bees learn quickly, so many calypsos are visited only once, and pollen may be removed but not deposited on another flower. Some researchers suggest that the slight variations in color and aroma that calypsos exhibit might facilitate fooling the bees into visiting more than one flower and accomplishing pollination.
The bees enter the open flower but discover no nectar and then back out. When they back up, apparently they hunch their backs and if, on the back of the thorax, they carried a pollinium from a previously visited flower, it gets brushed off on the stigma. A little farther toward the front of the flower, the backing-up bees encounter the pollinia of that flower, which in turn sticks to the back of the thorax, to be carried to another flower—unless the bee has learned its nectarless lesson. Calypso flowers may last more than eight days if not pollinated, but they wither in three or four days if pollination was successful. Apparently, fruit productions in calypso is generally poor, reflecting a low level of successful pollination.
We have one species of calypso here. I have seen it rarely, mostly in open, relatively dry areas. It is a temptation to pick Calypso flowers when one finds them, just because they are so lovely. But that seemingly simple act is likely to kill the plant, because the little, plucking tug can break the extremely delicate roots. So please don’t pick them!
There you have our orchids, and a lovely array it is. It is best not to try to transplant them, because many are delicate, and some are rare, so they should be left where they find themselves naturally. We can enjoy them in their natural places.
Thanks to Mary Stensvold and Ellen Anderson, USFS botanists, who provided helpful consultation.
When we think of parasites, we usually think of tapeworms, ticks, fungi, and assorted micro-organisms. But the world of flowering plants provides some interesting examples of a botanical version of parasitism, in which one plant extracts nutrients from another. We have two quite conspicuous and common kinds of flowering-plant parasites: hemlock dwarf mistletoe (Arceuthobium campylopodium) and northern ground cone (with the resounding name of Boschniakia rossica). Both of these species are entirely parasitic (or almost so). They derive all or almost all of their nutrients from their host plants and are unable to survive without a host.
You may have noticed the ‘witches brooms’ of gnarly, tangled branches that are the result of a mistletoe infection. The mistletoe alters the balance of growth hormones in hemlocks (and sometimes other species), causing the ‘brooms’. Male and female mistletoe plants are separate, with very small, inconspicuous flowers. Pollination is mostly by wind. When the seeds mature, they are discharged explosively; they are capable of travelling ten yards or more. Because they are sticky, they adhere to other branches or trunks and start new infections. This species has been reasonably well studied, because heavy infestations decrease the economic value of the timber.
The ground cone pokes up above ground in June. All we see is the cone-like inflorescence of tightly packed, brownish flowers; the rest of the plant is underground. Ground cone is commonly parasitic on the roots of alders, and sometimes other species, including blueberries. Various insects may visit the flowers and accomplish pollination; occasionally we have seen bumblebees probing the flowers. The seeds are minute and very numerous. The biology of this species apparently has not been studied in detail, as I can find no scientific papers on the subject, but the medicinal uses of this plant are reported to be many. We do know, from local observations, that bears frequently dig up and eat the underground base of the flowering stalk.
In addition, all orchids depend on their mycorrhizae (fungal associates) at least at some time in their life history. Some researchers consider the relationship to be mutualistic, with both participants gaining some advantages, and that eventually may be the case when the adult orchid develops green leaves and can provide carbohydrates to the fungus in return for soil nutrients. However, other researchers refer to mycorrhizal associations as a parasitism by the orchids on the fungi. This seems especially applicable in the case of orchids that develop little or no green tissue as they mature, so they can contribute nothing to their fungal associates. We have two species of the genus Corallorhiza (coralroot), one of which has no green tissue at all, while the other has a little and so can make some carbohydrates. They are both parasitic on fungi for all of their lifespans, but the relationships are even more complex: they can indirectly parasitize green plants through their fungi, which attach to the roots of trees and shrubs (which have their own mycorrhizae), and draw nutrients from those hosts.
Less well known are the so-called hemi-parasites, half parasitic and half independent. They have chlorophyll and can synthesize carbohydrates, but also commonly latch on to other plants and capture some nutrients from these hosts. We have a number of hemi-parasites among our local flowers.
The plant called yellow rattle or rattle box (Rhinanthus minor) grows in open areas at low elevations. This species is capable of parasitizing the roots of many other herbaceous species, including grasses. A single Rhinanthus plant can attach itself to the roots of several other plants. Some plants, however, are able to resist invasion by the roots of the parasite. Rhinanthus plants clearly benefit from the parasitic connections, growing and reproducing better if they are connected to a host. Some hosts, such as legumes, are better than others in providing the parasite with nutrients. In addition, the parasite can take up defensive chemicals, such as alkaloids, from the host, and thus reduce the risk of herbivory. The effects on the host plants are negative, because many of their nutrients are drained away by the parasite; parasitized hosts have decreased growth and reproduction; the negative impact is greater in some hosts than in others. There are indirect effects of Rhinanthus parasitism too: parasitized hosts have lower ability to compete with other plants in the community, and lower ability to recover from herbivory, which then affects the relative abundance of various species in the entire community.
Photo by Bob Armstrong
There are three species of Indian paintbrush (Castilleja) in Southeast, but only one has been studied much, and those studies were conducted elsewhere. In general, members of this genus grow better, flower more, and resist herbivory better, when they are connected to a host plant. Legumes seem to be better hosts than other plants, and two or more hosts may be better than one. When a parasitic paintbrush plant dies and decays, decomposition is accelerated, and co-occurring species have increased productivity, which may counter the usual negative effects of the parasite to some degree.
The genus Pedicularis—the louseworts–has about five representatives in our area, which have not been studied directly, as far as I can tell. In general, the negative effects of parasitism by different species of lousewort may vary among host species, and different louseworts have different host preferences. Some louseworts are reported to have mycorrhizal associations too, collecting nutrients via the fungal connection in addition to the usual direct parasitism.
Clearly, the world of the parasitic flowering plants is complicated, and it gets more complex as more studies are conducted. All those pretty (and not so pretty) flowers are intricately involved with many ecological interactions, and what we see above-ground is only a small part of the story.
slime molds, a berry cornucopia, and a beautiful poison
One bright, sunshiny day in mid August, we checked out the Peterson Lake trail, which is about four and a half miles long, and ends at cabin by the lake. There were rumors of recent trail improvements on the first three quarters of a mile. Indeed, there’s a section with a new base layer of angular, ankle-twisting cobbles, eventually to be covered by finer gravels; then there’s a section of packed dirt and, just before the big waterfall, a smooth section of finished trail.
After the big waterfall (where the steelhead have to stop, in the spring), the trails goes on as it has for years, with a section of packed dirt and slippery ‘corduroy’ logs and then boardwalks through the muskegs. At the Mile 2 marker, a long stretch of mud and roots winds through the forest until the lake finally appears.
The forest was very quiet on this day and no birds were evident, so those of us who are interested in natural history focused nearer the ground. A black slime mold had developed on a log: thousands of individual, independent cells had been feeding on bacteria and fungi in the soil, but now they had gathered together in a single mass for reproduction. Some of the cells will produce spores, while others serve as support structures for the spore-producing individuals. I wonder how they decide which cells will make spores!
The muskegs were dotted with several kinds of ripe berries, including black crowberries, bog blueberries, red bunchberries, and orange cloudberries. I was interested to find a large colony of timberberry in one of the muskegs, with several stems bearing the orange fruit. Timberberry is sometimes called pumpkin berry or, for no apparent reason, bastard toadflax—a name more correctly applied to a different species, but still for no known reason. The name game gets quite confusing, because this plant had been classified in two different genera at different times by different taxonomists. Sigh. The most interesting thing about this plant is that it is a hemi-parasite, drawing some of its nutrition from other plants while also having its own leaves. This is a very versatile parasite, capable of using many host species, such as spruce, alder, willow, currant, bunchberry, horsetail, asters, lupines, and dozens of others.
timberberry. Photo by David Bergeson
The lake level seems to be maintained in part by beaver dams at the outlet. After poisoning many of the resident fish some decades ago, the lake was stocked with juvenile rainbow trout (in the 1960s). A boat by the cabin gives ready access to all parts of the lake.
Along the trail, we noted several late-flowering monkshoods, one of our loveliest wildflowers, which grows at many elevations around Juneau. The complex, bumblebee-pollinated flower is usually a rich purple, although sometimes the purple is streaked with white. A fascinating feature of this plant is that ALL parts are reported to be very poisonous, but perhaps especially the roots and seeds. Eating even a tiny amount of this plant is likely to cause intense gastro-intestinal distress, followed by cardiac and respiratory failure if not treated immediately. And if you handle the plant more than casually, for example by picking leaves or breaking off the stems with your bare hands (not merely brushing by it as you walk), your skin can absorb the poisons. You are then likely to suffer the negative cardiac and respiratory symptoms, but without the gastrointestinal calamities.
The poisonous properties of monkshood have been known for centuries, and extracts of the plant have been used to make poisonous arrows for hunting or warfare, among other deadly uses. On the other hand, as is true of many plant poisons (think of digitalis, for instance), monkshood has also been used medicinally, in small, careful doses. It is a food plant for the caterpillars of several species of moth, which clearly have evolved physiological means of dealing with the poisons. And the bumblebees that pollinate the flowers either find a way to cope or else perhaps the nectar and pollen has less of the poison. Monkshoods are popular garden plants, but it is obvious that gardeners must handle this plant with great care!
On the Trails in Juneau 