TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora.

    THIS PAGE IS NO LONGER UPDATED
    AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY
  • Up-to-date information about California vascular plants is available from the Jepson eFlora.

ASTERACEAE

SUNFLOWER FAMILY

David J. Keil, Family Editor and author, except as specified

Annual to tree
Leaves basal or cauline, alternate to whorled, simple to compound
Inflorescence: 1° inflorescence a head, each resembling a flower, 1–many, generally arrayed in cymes, generally subtended by ± calyx-like involucre; flowers 1–many per head
Flowers bisexual, unisexual, or sterile, ± small, of several types; calyx 0 or modified into pappus of bristles, scales, or awns, which is generally persistent in fruit; corolla radial or bilateral (rarely 0), lobes generally (0)4–5; stamens 4–5, anthers generally fused into cylinder around style, often appendaged at tips, bases, or both, filaments generally free, generally attached to corolla near throat; pistil 1, ovary inferior, 1-chambered, 1-seeded, style 1, branches 2, generally hair-tufted at tip, stigmas 2, generally on inside of style branches
Fruit: achene, cylindric to ovoid, generally deciduous with pappus attached
Genera in family: ± 1300 genera, 21,000 species (largest family of dicots): worldwide. Largest family in CA. Also see tribal key to CA genera: Strother 1997 Madroño 44(1):1–28. See glossary p. 25 for illustrations of general family characteristics.

TETRADYMIA

COTTON-THORN, HORSEBRUSH

Shrubs
Stems ± tomentose
Leaves alternate and generally clustered in axils, linear to (ob)lanceolate, sometimes persisting as stiff spines, glabrous to tomentose
Inflorescence: heads discoid, axillary or in ± rounded, terminal clusters; involucre cylindric to hemispheric; phyllaries in 1–2 ± equal series, often keeled; receptacle naked
Disk flowers generally 4–8; corollas cream to yellow, lobes long, spreading; anther bases ± sagittate, tips obtuse or acute; style branches papillate to short-bristly, tips truncate to conic
Fruit obconic or fusiform, often angled; pappus 0 or of generally many bristles or slender scales
Species in genus: 10 species: w North America
Etymology: (Greek: 4 together, from 4-flowered heads of some)
Reference: [Strother 1974 Brittonia 26:177–202]
Esp flower buds TOXIC to sheep (toxicity poorly understood).

Native

T. tetrameres (S.F. Blake) Strother

Plant < 20 dm, unarmed
Stems tomentose
Leaves sparsely tomentose; main leaves 1–4 cm, linear, thread-like, soft; clustered leaves 10–20 mm, thread-like to linear-oblanceolate
Inflorescence: heads generally 4–6 on short side branches; peduncles generally 1–3 mm, tomentose, bracts 0–2; involucre 8–9 mm, obconic; phyllaries 4(5), widely elliptic
Flowers 4(5); corollas ± 8 mm, pale yellow
Fruit 5–6 mm, densely long-soft-hairy; pappus of ± 20 stiff bristles or slender scales, 3–5 mm, ± hidden by fruit hairs
Chromosomes: 2n=60
Ecology: Dunes, deep sand, sagebrush scrub
Elevation: 1200–2100 m.
Bioregional distribution: n East of Sierra Nevada
Distribution outside California: w Nevada

previous taxon | next taxon
bioregional map for TETRADYMIA%20tetrameres being generated
 


Retrieve Jepson Interchange Index to Plant Names entry for Tetradymia tetrameres
Retrieve dichotomous key for Tetradymia
Return to treatment index page
Glossary
University & Jepson Herbaria Home Page | Copyright © by the Regents of the University of California