Lithophragma parviflorum / smallflower woodland star

Adjectives: clonal, forest openings, interesting bits, native, showy, widespread

Also known as: woodland star, prairie star, prairie rockstar, small-flowered fringe-cup

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The woodland star is a small, rhizomatous, perennial herb. Its small flowers jump out at you as you walk the trails because of their star-like appearance… each of the 5 petals is deeply 3-lobed. Actually, because the petals are somewhat different sizes, they flowers may look pentagonal in outline. Usually, the flowers are bright white but a pinkish/purple/mauve variant is not uncommon. That variant is reportedly fragrant, but that may have as much to do with our sniffers as with the flowers themselves (see below).

Each flowering stalk – inflorescence – may have as many as 14 flowers, although fewer are the norm. Initially, the flowers look clumped together, but the stalk elongates as they open. This tends to make it clearer that the inflorescence is of the raceme persuasion. Although the flowers themselves are quite striking, if you look more closely, each is held in a cup-like calyx of red or green sepals. This is an important feature as far as some pollinators are concerned (again, see below).

The leaves of woodland stars are located low on the stem… the flowering stem itself has no leaves. Each leaf is dissected into three lobes and they are hairy and glandular, and commonly purple or reddish on the upper surface.

Woodland stars are widespread, growing in grasslands, sagebrush plains, dry open areas, open forests and meadows. They are found from the floor of the Valley to high up on mountain trails. You will especially see them in spring (through June) but probably not in profusion.

L. parviflorum is not the only Lithophragma species in the state, but may be the only one in the Valley. In any case, it can be distinguished from other species in the genus by its lack of tiny maroon beads (bulblets) in leaf axils and in place of some flowers. In addition to rhizomes, these bulblets are a means of clonal reproduction.

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Interesting bits – Now back to the floral scent. First of all, L. parviflorum is insect pollinated.  That is, of course, not unusual. We all know about the birds and the bees. The major insect group – accounting for between 70 and 90% of the pollinator visits – is  bombyliid flies. These look more or less like bees (and are sometimes called bee flies), and they are parasitoids, i.e. their larvae eat other insects. The adults eat nectar and pollen.

Beyond those, however, is the moth, Greya politella. Both male and female moths visit the flowers and probe for nectar, but it is only when the females insert their ovipositors (their egg laying tails) into the flowers that pollen is actually transferred (see the photo to the left). What they are really doing, however, is laying eggs that will hatch into larvae that will eat up to a quarter of the seeds that result. In other words, the moths are both pollinators and parasites of the same flowers.

About the floral scent (as I said before, I know)… a 2013 article from Friberg and co-workers at UC Santa Cruz reported a comparison of floral scents from 4 species of Lithophragma. It seems, by chemical analysis, that floral scent is a very complex thing and that the different species had very different compositions. These little, easily overlooked plants make 69 different compounds that contribute to the floral scent. Regardless of the combinations of chemicals, all the species and variants were visited and parasitized by G. politella.

So, the next time you run across this wonderful flower, think on all plants and how amazingly complex their evolution and biochemistry is, even if they just look like sort-of-pretty little flowers.