Arrow-leaved Groundsel (Senecio triangularis)
One of the more common and easy to identify of the dizzying array of yellow composite flowers; we were surprised to find we hadn’t yet posted it. Look for the notched, arrowhead-shaped, alternate, toothed leaves, and heads of small, never-perfect, disk flowers. It blooms late on the west side of the Cascades, in moist areas, particularly in the subalpine zone. We’ve posted other similarly shaped senecios (also commonly called ragworts), including the White Western (white flowers) and the Black-tipped (black tips on disk flowers, found mostly in Alaska and Canada) grounsels.
According to Charles Stewart, in Wildflowers of the Olympics and Cascades, “the bare seed receptacle is supposed to resemble a bald head”, giving the latin senecio, from senex (where the word “senile” comes from), meaning “old man”. Elizabeth Horn begs to differ, however, claiming, in Wildflowers 1, that the name comes instead from “the downy white hairs on the seed heads, which are supposed to look like an old man’s hair.”
Over two thousand species of senecios have been identified across the globe, some grow as tall as small trees. Triangularis generally tops out around two feet. Pronounced sen-ee-see-o, with the accent on the second syllable.