Cheering notes

floral memories brighten a gloomy winter

As I sat here on yet another gray and drippy day in mid-January, grousing futilely and needing a cheering thought, there popped up a memory from my old life in the Midwest (probably prompted by recent reading). There are many things in the Midwest that I miss, and one of them is the deciduous forest with its many kinds of flowers in the understory; there are well over a dozen species. It’s a spectacular show in early spring (when my grad students and I did research on seven of them), and other species come along later on.

Many of these early species take advantage of the open canopy that lets in plenty of light before the trees leaf out. The light is used to make carbohydrates for energy (needed for growth and seed development) and a bit of warmth facilitates the activity of insect pollinators. Even the species that don’t flower until later in the season can build up stores of energy to be used at their proper time. I think that the availability of light is probably one of several factors contributing to the floral diversity in the deciduous forest.

All that made me think about our coastal rainforest, whose floor is mostly shades of green, lovely in its own way but scarcely as showy. Here in the coastal coniferous forest, the understory is always dark; the canopy blocks lots of light all year long. And only a few flowers thrive throughout the forest; several others are happier in somewhat brighter places on the forest edges or in canopy openings, although they are sometimes found scattered within the forest.

Whatever the reasons for the dearth of understory flowers here, I chose to contemplate the flowers that regularly decorate the forest floor. They are little points of delight, good to envision on dark day even though their blooming time is still months away.

Bunchberry flowers. Photo by Bob Armstrong

–bunchberry or dwarf dogwood: very widespread in the forest, the four white bracts around a central cluster of small flowers make a good showing. The flowers release pollen in an unusual way: by a special catapult mechanism that throws the pollen up several centimeters. The flowers open elastically, explosively, and extremely rapidly (in less than a millisecond), flipping the pollen-bearing anthers upwards. Flowers may open spontaneously, tossing pollen up into the breezes, or when triggered by the visit of a large insect such as a bee, tossing pollen onto the insect’s body to be carried to another flower. Later on, the clump of red berries is equally showy. The leaves are typically evergreen, but sometimes turn red.

Rattlesnake plantain flowers. Photo by Bob Armstrong

–rattlesnake plantain: an orchid that has nothing to do with snakes or plantains, whose evergreen leaves are sometimes mottled with dark blotches. It produces a spike of white flowers that may be bumblebee-pollinated but are reported to be more often visited by moths in our area. Like all orchids, it depends on mycorrhizal connections with other plants for seed germination and early seedling growth; this mutualism may also supplement the nutrition of adult plants. This orchid can spread vegetatively by rhizomes (underground stems), and we often see patches of it with many nonflowering stems.

Fern-leaf goldthread, male flowers. Photo by Bob Armstrong

–fern-leaf goldthread: the flowers are small and delicate, often male, but sometimes hermaphroditic (both male and female). An individual plant can be change sex expression from year to year; if it produces energy-expensive seeds in one year, it is likely to be male or non-flowering the next year. Later in the season, fruiting plants make an interesting whorl of seed capsules that fling out the seeds when jostled. The leaves are evergreen. Although it is found in dense forest, survival of young plants is better where the shade is less dense. The flowers are pollinated by small flies, such as dance flies.

Single delight. Photo by Bob Armstrong

–single delight or shy maiden: An evergreen member of the wintergreen family, its white flower faces downward until it is pollinated, when the flower raises its face upward, exposing the seed capsule with the tiny seeds to the breezes. The flower is buzz-pollinated by pollen-collecting bumblebees, which vibrate the anthers to release pollen onto the foraging bees.

Western coralroot. Photo by Bob Armstrong

–western coralroot: Spikes of pinkish flowers on pink stems usually appear in groups. There is no green pigment at all and no capacity for photosynthesis; these plants are indirectly parasitic on trees and shrubs, via mycorrhizal fungal connections, and also may be saprophytic (feeding on decayed organic matter). The flowers are visited by bees.

Those species all grow under dense coniferous canopy and are seldom seen outside the dark forest. It seems likely that they are able to inhabit the deep shade because they are evergreen and therefore capable of photosynthesis at any time of year if it’s warm enough, or dependent on other sources of energy. All can spread vegetatively to some degree, by means of rhizomes, and probably all of them form mycorrhizal associations with other plants. At least some of them, including rattlesnake plantain, seem to flower infrequently, suggesting that energy resources may be limited. Self-pollination may occur in some of them, with or without an insect visitation.

One other species is often considered to thrive in dense, moist forest in western North America: three-leaf foamflower. Unlike the previous species, foamflower is not evergreen; it reportedly does somewhat better under less dense canopies and is also seen along trails in more open areas. It would interesting to know how it manages in the deep forest. Other species are sometimes found in the forest, but usually in more open parts of the woods or on the edges: examples include starflower, calypso orchids, three-leaf goldthread, twinflower, two species of twisted-stalk, and violets.

Whether bona-fide deep-forest denizens or dwellers on the fringes, they all provide visual delights, sometimes olfactory treats (twinflower, maybe rattlesnake plantain), and interesting natural history.

Recent sightings

…a collection of small discoveries from recent walks.

Along the road to the Eagle’s Nest and Pittman Ridge, there was a small stand of fireweed that stood out from the rest. The petals were white, while the narrow sepals showing between the petals were the usual vivid pink. A very showy display.

Photo by Kerry Howard

At Point Louisa, on a moderately low tide, the rocky shores and pools held the usual assortment of sea stars, chitons, anemones, and urchins. I was entertained by a couple of urchins: in one pool, the urchin sat in a clam-shell bowl that was a perfect fit. And in the next pool, another urchin wore a sizable clam shell as a hat, which covered the urchin completely, to the very tips of its spines—another perfect fit. Urchins often bear stones or bits of shell on their spines, possibly for camouflage or, in some places, perhaps protection from UV light.

A stroll on Eagle Beach brought a surprise—two woolly-bear caterpillars (Lophocampa maculata). One marched steadily along the sand, struggling a bit over small divots of loose sand, but persevering. The other one trudged rapidly up toward the rye grass, made a ninety-degree turn and scurried along for several yards, and then made another right-angle turn back down toward the damp sand near the water’s edge. Both explorers visited milkwort and goose-tongue plants but did not seem to eat anything. According to various sources, these caterpillars customarily eat the leaves of poplar, willow, and alder, so it was a puzzle just why they were down on the beach. If they were looking for a place to pupate, this wasn’t it!

Along a short stretch of the Treadwell Ditch trail we found a series of piles of red bunchberries. Each berry had been opened, and the single fat seed extracted. Surely the work of a rodent—a squirrel or maybe a mouse. In contrast to that pattern of consumption, on Gold Ridge we found some patches of bunchberry in which the berries had been systematically pecked open, removing bits of fruit pulp but leaving the seeds intact. Birds, no doubt, but which? There are very few reports in the natural history literature of birds eating bunchberries.

Skunk cabbage fruiting stalks are starting to fall over and ‘melt’ into puddles of ooze containing lots of seeds. When I first arrived in Juneau, many years ago, I found some of these things that had just fallen over and started to take up water (before the oozy stage). At that earlier stage, each seed was surrounded by a jelly coat, and I (being new in the area and quite ignorant of local matters) took the aggregations of jelly-coated seeds to be frog eggs. But what were those ‘eggs’ doing in the middle of the forest??? Ah well, I learned! On a recent walk, I found the remnants of a skunk cabbage fruiting stalk, with the central pith intact, indentations showing where the seeds had been, and no seeds on the ground. The pithy center had been plucked clean by a seed-predator, such as a squirrel, or a jay, or a flock of chickadees, or…who knows?

Gold Ridge provided several additional observations of interest: A tangle of brush suddenly shook vigorously, drawing our attention. In the middle of the tangle, a red squirrel harvested a cluster of the devil’s club berries and made off with it. We often see devil’s club seeds dispersed by bear scats, but this was the first time (that I can recall) I’d seen a squirrel presumably intent on having the seeds for lunch. Farther up the trail, we surprised a well-grown ptarmigan chick, and stopped to watch. The chick was apparently not too sure what to do: it ran up the trail a little way, came back, turned around and ran up several yards, came back, and finally took off up the trail and into the brush. I was charmed by the fluttering of the white feather over its legs—like lacey pantalettes.

Time out for tea and crumpets at a rocky viewpoint, with marmots whistling on all sides (a couple of illegally off-leash dogs had just gone up the trail). Time, then, to examine our immediate surroundings more closely. Here’s a patch of trailing raspberry, in the subalpine zone, not its usual forest habitat. The pretty little rosettes of pussytoes leaves; the tiny, now-empty, artistic seed capsules of white mountain heather; a lonely purple flower of the miniscule moss gentian. The odd growth pattern of the alpine harebell, with the single flower borne on a stem that seems to emerge from underneath a low rosette of leaves.

A nearby stand of copperbush was covered with immature fruits of a curious shape, rather like small green pumpkins with curved handles on top. I was reminded of the stones used for the game of curling. A few laggard copperbush flowers attracted some bumblebees, who did not linger long.

Hmmm….pumpkins and curling stones, pantalettes, and who knows what else might we find!?

Tricky flowers

…clever little arrangements for pollination

Most of our wild flowers are wide-open structures, just letting all the sexual parts hang out. Think of nagoonberry or cloudberry, asters, avens, silverweed, wild roses, geranium, anemones, and so on—all of these just present the sexual organs to whatever insect happens to land there. The smaller flowers of angelica and cow parsnip and their relatives do the same, but present the flowers in flat-topped bunches, making a good-sized landing platform for a visiting insect. It is then a relatively simple matter for an insect to walk around, picking up pollen from one flower and carrying it to another. Columbine and fernleaf goldthread dangle the sex organs loosely, downward or outward, where a visitor just bumps into them, when in search of nectar deeper in the flower.

Some of our flowers, however, are a bit more complex, requiring a visiting insect to do a little work or behave in a particular way. In these species, the sexual parts are typically enclosed within the flower—concealed in various ways. Here are some examples:

Lupine. Photo by Bob Armstrong

Lupine: Bees pry open the flower, and when they depress the lowest, keel-like petal, out pop the stigma (to receive pollen, if the bee carried any) and the anthers (containing pollen to be deposited on the bee and carried to another flower).

Twayblade orchid: A visiting tiny bee or fly pokes into the miniscule flower, bumping into a projection that releases a sticky gob that pulls out clumps of pollen. The pollen is stuck onto the insect’s face or head until another flower is visited and the pollen is inserted there.

Violet: Down in the heart of the flower, the stigma is encircled by closed anthers, packed tightly together (the technical term is ‘connivent’—conjuring up mental images of conniving and scheming deviously (!). A visiting insect displaces the stigma, pushing it to one side and perhaps depositing pollen, and only then do the anthers open, releasing pollen to be picked up and carried away by the insect.

Bog cranberry. Photo by Bob Armstrong

Blueberry, cranberry, shooting star, wintergreens (and tomato): Although the flowers differ in shape, all depend on what is called ‘buzz pollination.’ A visiting bee vibrates certain flight muscles (and buzzes), which causes pollen to shake down on the bee. If the bee already had pollen on its body, from another flower, it is brushed off onto the stigma.

Bunchberry/dwarf dogwood: the tiny flowers are clustered together, surrounded by white, petal-like bracts. Ripe flower buds open suddenly and the anthers explode their pollen into the air or onto an insect, when a tiny projection on one of the four petals is triggered, perhaps by an insect.

Lady-slipper orchid/moccasin flower: These flowers are doubly devious. They offer no nectar to insect visitors, who nevertheless prospect around inside the ‘slipper’, in hopes of a reward. But once inside that slipper, they cannot get out—except by squeezing through a tight opening at the back of the flower, where the sexual organs just happen to be located, convenient for pollen deposition and pick-up.

Bog laurel. Photo by Bob Armstrong

Bog laurel: When the flower opens, the anthers are held in little pockets on the faces of the petals, with slim filaments linking them to the center of the flower. This species is normally pollinated by bumblebees: when the bee lands on a flower, the anthers spring out of their pockets and dust pollen on the bee. The springing mechanism is reported to be very sensitive, so perhaps even small insects, coming in search of nectar, can spring the anthers free, but it is unclear if the pollen would land on their bodies and if they would be effective pollinators.

All these clever little arrangements are a small sample of the ingenious contrivances for pollination exhibited by flowers in more southerly latitudes, about which whole books have been written. The world of flowers is far more complicated than one might expect.