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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.
Annual 1–15(20) cm, gray to green, cobwebby to woolly or tomentose. Stem: 1, erect, or 2–10, ascending to prostrate, generally ± forked, ± leafless between forks. Leaf: generally opposite (distal ± alternate), ± sessile, linear to ovate or obovate, entire; distal leaves subtending heads, crowded, largest > proximal leaves. Inflorescence: heads disciform, sessile, single or 2–4 per dense group, generally spheric; involucre 0, simulated by paleae and leaves; receptacle length 1–2 × width, ± obovoid, glabrous (generally not lobed); paleae of pistillate flowers each enclosing flower, deciduous with fruit, ± obovoid or cylindric, length generally < 3 × width, obtuse, bulged out and hood-like distally, tomentose to woolly abaxially, prominently net-veined, veins 5+, margin ± reflexed distally as scarious wing, wing adaxially lateral, generally at >= 2/3 palea, projected inward, hidden in head, ± beak-like; paleae of disk flowers 0. Pistillate flower: (8)20–100+, all subtended by paleae; corolla obscure, narrowly cylindric. Disk flower: staminate, 2–10; pappus 0; corolla 4–5 lobed; anther base tailed, tip ± triangular; style tips ± linear-oblong. Fruit: each enclosed by palea, ± club-shaped (then ± compressed laterally) to ± cylindric, smooth, shiny, corolla scar ± terminal; pappus 0.
5 species: western North America, southern South America. (Greek: slender chaff) [Morefield 2006 FNANM 19:456–460] Species sometimes appear to intergrade where ranges overlap; needs study.
1. Largest heads 6–14 mm diam; paleae generally ± hidden by hairs, longest 2.8–4 mm
2. Largest heads 9–14 mm, ovoid, silky-tomentose, receptacle deeply lobed; paleae ± cylindric, length generally 3.5–6 × width, wing at ± 1/2 palea length ..... P. brevissimus var. multiflorus
2' Largest heads 6–9 mm, ± spheric, generally woolly, receptacle not or shallowly lobed; paleae obovoid, length 1.5–3 × width, wing at >= 2/3 palea length
3. Distal leaves generally lanceolate to ovate, longest generally 8–15 mm, 1.5–4 × width; plants generally woolly; stems (1)2–10; fruit ± club-shaped ..... P. brevissimus var. brevissimus
3' Distal leaves generally oblanceolate to linear, longest generally 17–35 mm, 4.5–9 × width; plants generally silky-tomentose; stems 1(3); fruit ± cylindric ..... P. elatior
1' Largest heads generally 3–6 mm diam; paleae ± visible through hairs, longest 1.5–2.7 mm
4. Distal leaves linear to narrowly oblanceolate, generally 6–12 × width, (3)3.5–5 × heads; fruit ± cylindric ..... P. oregonus
4' Distal leaves spoon-shaped to obovate or ovate, generally 1.2–5 × width, 1–2.5(3) × heads; fruit ± club-shaped
5. Distal leaves ± appressed to heads, ovate to widely elliptic, generally 1.2–1.8(2) × width; proximal stem internodes (2)3–6 × leaf lengths; disk flower corolla generally 4-lobed ..... P. chilensis
5' Distal leaves generally ± spreading, spoon-shaped to obovate, generally 2–5 × width; proximal stem internodes generally 1–2(3) × leaf lengths; disk flower corolla generally 5-lobed ..... P. tenellus
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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