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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

HESPEREVAX

James D. Morefield


Annual 0.5–10(20 cm), ± green to gray, woolly to cobwebby. Stem: 0, or 1, erect, or 2–10, ± decumbent to ascending, generally unbranched or branched proximally, equally or more leafy distally. Leaf: alternate, sessile or petioled, oblanceolate to spoon-shaped, entire, base ± yellow, ± hard; distal leaves subtending heads, ± crowded, largest >= proximal leaves. Inflorescence: heads disciform, sessile, single or 2–40+ per group; involucre 0, simulated by paleae or leaves; receptacle length 0.8–1.3 or 4–6 × width, ± conic, acuminate, bristly; paleae of pistillate flowers open, lanceolate to obovate, acute, flat to concave or ± folded, persistent, ± glabrous, obscurely parallel-veined, veins 5+, margin ± continuous, thinned but scarcely winged; paleae of disk flowers generally 5, ± enlarged, erect proximally, erect to spreading distally, open, obovate, obtuse, cartilaginous, proximally ± yellow, distally green and tomentose adaxially. Pistillate flower: (3)5–25, all subtended by paleae; corolla obscure, narrowly cylindric. Disk flower: staminate, 2–6(12); pappus 0; corolla (3)4(5)-lobed, ± bilateral; anther base tailed, tip ± triangular; style tips ± linear-oblong; pappus 0. Fruit: falling free of paleae, ± obovoid, compressed front-to-back, smooth, dull to ± shiny, corolla scar terminal; pappus 0.
3 species: western California, southern Oregon. (Greek: western Evax) [Morefield 2006 FNANM 19:467–470] Apparent sister of Ancistrocarphus; bristly receptacle unique. Historical California specimens of Diaperia [Evax sect. Diaperia], native central Arizona and eastward, are likely label errors.
Unabridged references: [Morefield 1992 Syst Bot 17:293–310]

Key to Hesperevax

1. Distal heads 3–5 per group, ± terminal, ± cylindric, length 1.8–2.5 × width; groups loose, subtended by generally 1–4 leaves; paleae of disk flowers 0.3–0.4 × head, tips included, ± erect ..... H. sparsiflora

2. Largest leaves 6–12(14) mm, 3–5(6) mm wide; blade ± round, woolly ..... var. brevifolia

2' Largest leaves (10)13–32 mm, 4–8(10) mm wide; blade oblanceolate to obovate, silky-cobwebby ..... var. sparsiflora

1' Distal heads 1 or (2)10–40+ per group, terminal, bell-shaped or ± obconic, length 1–1.5 × width; groups dense, subtended by 6–20 leaves; paleae of disk flowers 0.6–0.9 × head, tips exserted, spreading

3. Longest leaves (25)33–90 mm, 7–20 mm wide; petiole 2–3 × blade, base strongly thickened; heads 10–40+ per group, largest group 10–25 mm wide, subtended by (not mixed with) leaves ..... H. caulescens

3' Longest leaves 4–22(32) mm, < 5 mm wide; petiole 0–1.5 × blade, base scarcely thickened; head generally 1, distal heads rarely 2–8 per group, largest group 3–7 mm wide, mixed with leaves ..... H. acaulis

4. Stem ± erect; largest leaves (9)12–22(32) mm, 2–4(5) mm wide; longest paleae of disk flowers 2.5–3.2 mm ..... var. robustior

4' Stem ± prostrate or 0; largest leaves generally 4–12 mm, 0.5–2 mm wide; longest paleae of disk flowers 1.6–2.4 mm

5. Largest leaves generally 7–12 mm, 0.5–2 mm wide; petiole 0–0.8 × blade; blade oblanceolate, acute ..... var. acaulis

5' Largest leaves generally 4–7 mm, 1–2 mm wide; petiole generally 0.5–1.5 × blade; blade obovate to round, obtuse ..... var. ambusticola

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Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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