Congdon's Buckwheat

Eriogonum congdonii is an elegant subshrub restricted to the mountains of central-northern California (southern Siskiyou and northern Trinity counties). It is worthy of serious consideration as a garden introduction even though it typically occurs on nearly raw, greenish-black serpentine outcrops. In that setting, the olive green leaf blades, the bright green and nearly glabrous flowering stems and inflorescence branches, and the dense clusters of rich sulphur-yellow flowers make a beautiful contrast.

Subshrubs, spreading to erect, synoecious, 1.5-5 × 1-3 dm, floccose or glabrous. Stems: caudex spreading to somewhat erect; aerial flowering stems erect, slender, solid, not fistulose, arising at nodes of caudex branches and at distal nodes of short, nonflowering aerial branches, 1-2(-2.5) dm, thinly floccose or glabrous. Leaves in rather compact basal rosettes; petiole 0.2-0.8 cm; blade narrowly elliptic to narrowly oblong, 0.5-2 × 0.3-0.6(-0.8) cm, densely white-tomentose abaxially, thinly floccose or glabrous and olive green adaxially, margins entire, revolute. Inflorescences umbellate, 0.3-3 × 1-3.5 cm; branches thinly floccose or glabrous; bracts 3-4, semileaflike, lanceolate, 0.1-0.5 × 0.1-0.3 mm. Involucres 1 per node, turbinate, 5-6 × 3-4 mm, tomentose; teeth 6-8, erect, 0.5-2 mm. Flowers 4-6 mm, including 0.4-0.6 mm stipelike base; perianth sulphur yellow, glabrous; tepals monomorphic, obovate; stamens exserted, 4-5 mm; filaments pilose proximally. Achenes light brown, 4-5.5 mm, glabrous except for sparsely pubescent beak.

Calif.

Flowering Jul-Sep.

Gravelly serpentine slopes and outcrops, manzanita communities, montane conifer woodlands; (1000-)1500-2300m.

Eriogonum ursinum S. Watson var. congdonii S. Stokes, Eriogonum, 114. 1936 (as congdoni); E. ternatum Howell var. congdonii (S. Stokes) J. T. Howell

Eriogonum congdonii is a species of wild buckwheat known by the common name Congdon's buckwheat. It is endemic to the Klamath Mountains of northern California, where it is an uncommon member of the serpentine soils flora in the local forests. It is a low, matting shrub growing up to about half a meter wide and tall. The woolly leaves are widely lance-shaped and are found along the stems, especially in clusters at the stem tips. The inflorescence is an erect, dense umbel of many tiny bright yellow flowers.