Eriogonum twisselmannii (J. T. Howell) Reveal

Eriogonum twisselmannii is a rare species of the southern Sierra Nevada and is known only from Slate Mountain and The Needles in Tulare County. It is worthy of being on a “watch” list of rare plants in California, but because of its remote location, it is not threatened.

Herbs, matted, occasionally polygamodioecious, (0.2-)0.5-1.5 × 3-4 dm, tomentose. Stems: caudex spreading; aerial flowering stems erect or nearly so, slender, solid, not fistulose, arising at nodes of caudex branches and at distal nodes of short, nonflowering aerial branches, (0.2-)0.5-1.2 dm, tomentose, with a whorl of 4-8 leaflike bracts ca. midlength, similar to leaf blades, 0.4-0.8 × 0.1-0.3 cm. Leaves in loose to congested basal rosettes; petiole 0.2-0.4 cm, thinly tomentose; blade oblanceolate to elliptic, 0.5-1 × (0.2-)0.4-0.6 cm, white- or grayish-tomentose abaxially, thinly tomentose to nearly glabrous and dull green adaxially. Inflorescences capitate, 0.7-1.5 cm wide; branches absent; bracts absent immediately below involucre. Involucres 1 per node, campanulate, (2.5-)4-5 × 4-6 mm; teeth 6-9, lobelike, strongly reflexed, (2-)3-5 mm. Flowers (4-)5-6 mm, including 1-1.3 mm stipelike base; perianth pale yellow, villous abaxially; tepals slightly dimorphic, those of outer whorl obtuse, 3-5 × 3-3.5 mm, those of inner whorl broadly oblanceolate, 5-6 × 2.5-3 mm; stamens exserted, 4-5 mm; filaments pilose proximally. Achenes light brown, 5-5.5 mm, glabrous except for sparsely pubescent beak.

Calif.

Flowering Jun-Sep.

Rocky outcrops, montane conifer woodlands; of conservation concern; 2300-2600m.

Eriogonum douglasii Bentham var. twisselmannii J. T. Howell, Leafl. W. Bot. 10: 13. 1963