Lobes linear and pointed, pinnately dissected, usually 3-5 lobes, which themselves may be pinnately subdivided (bipinnate), 1-5 cm long, forming an obovate overall shape, with lobe axes crossing the main leaf axis at roughly right angles. The margins are revolute, or rolled under, making the margins look even narrower. The leaves are green glabrous above and densely tomentose or woolly below, giving the plant a grey-green appearance overall. Inflorescences form dense terminal cymes (flat-topped clusters) at the tops of stems. These contain 3-30 individual heads on peduncles ranging from 0 to 25 cm in length. The involucres (a whorl of phyllaries or bracts, which in composite flowers look like the calyxes of sepals under a simple flower) below the heads are 3-7 mm long, bell-shaped, tomentose (woolly). There are 4-6 ray flowers, bright yellow, ~2-5 mm long. There are 10-75 disk flowers, also yellow, about 2-4 mm long, which are puberulent (minutely fuzzy) or glandular (sticky). Blooms from April to August. Fruit is an achene (dry 1-seeded fruit), flattened or club shaped, 2-4 mm long, with a very short (<1 mm) pappus (fringe of hairs). Plant is a subshrub (small shrub woody mainly at the base but more herbaceous higher up), 0.2 to 0.7 m in height. The plant favors dry slopes and washes under 3000 m in elevation in the Coast, Transverse, and Peninsular ranges, the Sierra Nevada and its foothills, and the western edges of the Mojave and Colorado/Sonoran deserts, extending into Baja.
Eriophyllum confertiflorum (Asteraceae aka Compositae): golden yarrow or yellow yarrow
The development of this key was partially funded through the Geoscience Diversity Enhancement Program (Award #0703798) and through a course of re-assigned time provided by the CSULB Scholarly and Creative Activities Committee. Thanks also to the students in sections of biogeography, introductory physical geography, GDEP, and LSAMP for "test-driving" various editions of this key.