Giant Yarrow

Achillea gigantea Pollard, Bull. Torrey Club 26: 370. 1899
A robust perennial, with a rootstock; stem nearly 1 m. high, often much branched, sulcate, densely long-Tllous ; stem-leaves 5-10 cm. long, bipinnatifid, linear-lanceolate in outline, densely longvillous; primary divisions short, crowded, the ultimate ones linear to ovate, usually obtuse, 1-2 mm. long; heads in dense many-branched corymbiform panicles, with densely pubescent branches; involucre 5-6 mm. high, about 4 mm. broad; bracts greenish-yellow throughout, the outer acutish, ovate, the inner oblong, rounded at the apex; ray-flowers about 5; ligules very small, 1-1.5 mm. long; disk-flowers about 30; corollas yellowish-white; achenes elliptic, obscurely margined.
Type locality: Tulare Lake, California.
Distribution: Type locality, in Owen's Valley, and near Fort Tejon, California.