Plant of the Week
Smoothstem blazingstar (Mentzelia laevicaulis)
By Walter Fertig
The blazingstars or stickleafs (Mentzelia) are sometimes known as nature’s Velcro because of the ease with which their leaves become fastened to fur or fabric. These sticky qualities derive from numerous hairs found on the leaf surface, each of which is ringed by barbs or downward-pointing bristles. The adaptive value of this stickiness is poorly known, though the authors of the Intermountain Flora have suggested that the force of an animal tugging against the plant may be sufficient to shake seeds out of the fruit capsules.
Smoothstem blazingstar (Mentzelia laevicaulis) is a biennial or short-lived perennial with whitish stems up to 40 inches tall and wavy-margined, sticky leaves. It ranges widely across western North America from southern Canada to California, Utah, and Colorado, inhabiting barren slopes and disturbed roadsides. This species is unusual within its genus of 60 species (nearly all found in the western United States) in having exceptionally large flowers (1½ to 3 inches across) with just 5 yellow petals. Most other species in the genus have 8 to ten or more petals, with the extras derived from modified stamens. Similar to cultivated, multi-petaled roses, the filament stalks of the stamen have become widened and enlarged into petal-like structures and have lost the pollen-producing services of the anther. The flowers of smoothstem blazingstar open at dusk and remain open overnight and into early morning before closing for the afternoon. Hawkmoths are thought to be the primary pollinator.
If pollinators are absent, smoothstem blazingstar is capable of self-pollination. Typically, the stigma is held above the fertile anthers when the flower first opens. As the blossom closes in the afternoon, loose pollen is knocked into the floral envelope and can contact the stigma. Whether cross or self-pollinated, this species produced numerous, flat, wing-margined seeds within a woody capsule. Native Americans consumed these seeds for food. Indigenous peoples also utilized the roots of smoothstem blazingstar to treat pain from arthritis, rheumatism, and bruises.
Intrepid botanical explorer David Douglas (of Douglas-fir fame) made the earliest scientific collection of smoothstem blazingstar near the Great Falls of the Columbia River in 1825. Douglas initially named the species Bartonia laevicaulis after Benjamin Smith Barton, one of the leading American botanists of the early 19th Century and a mentor to Meriwether Lewis. Unfortunately, the genus name Bartonia was already taken, and the name was changed to Nuttallia to honor Thomas Nuttall, the 19th Century British botanist who discovered and named a large number of western plant species. Alas, this name too was later changed when Nuttallia was subsumed into the genus Mentzelia. No genus name now honors Nuttall.