|Jepson Flora Project: Jepson Interchange|
|TREATMENT FROM THE JEPSON MANUAL (1993)||
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Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
AND IS MAINTAINED FOR ARCHIVAL PURPOSES ONLY
Annual to tree
Leaves basal or cauline, alternate to whorled, simple to compound
Inflorescence: 1° inflorescence a head, each resembling a flower, 1many, generally arrayed in cymes, generally subtended by ± calyx-like involucre; flowers 1many 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)45; stamens 45, 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):128. See glossary p. 25 for illustrations of general family characteristics.
Annual, gray to green, cobwebby to tomentose
Stems generally several from base, generally spreading, < 20 cm, ± forked; central axis generally 0 or not dominant
Leaves simple, generally opposite, ± sessile, < 3 cm, ± obtuse, entire (uppermost ± alternate or seeming whorled, generally ± appressed to heads)
Inflorescence: heads disciform, sessile, solitary or in small groups, generally spheric; bracts like leaves; phyllaries 0; receptacle 12 X > wide, ± obovoid, generally entire, chaffy; chaff scales each enclosing a pistillate flower, falling with a fruit, length generally < 3 X width, generally ± obovoid, bulged upward, woolly, net-veined, tip scarious-winged, offset to inner edge, generally ± 2/3 the distance from base to top of scale, projected inward, beak-like, hidden in head
Pistillate flowers in many series, each subtended by a chaff scale; corollas tubular
Disk flowers staminate, 210, not subtended by chaff scales; ovary vestigial
Fruit smooth, shiny; pappus 0
Species in genus: 35 ill-defined species: w North America, s South America
Etymology: (Greek: slender chaff)
Reference: [Cronquist 1950 Res Stud State Coll WA 18:7189]
Spp. appear to intergrade, need detailed study.
Plants variously tomentose
Stems several from base or branched above, spreading to erect; central axis various
Leaves: uppermost generally lanceolate to ovate, longest 825 mm, 1.56 X > wide
Inflorescence: largest head 614 mm; longest chaff scale generally 2.84 mm
Disk flowers 0.81.6 mm, (4)5-lobed
Fruit 0.81.9 mm, ± obovoid
Ecology: Vernal pools and flats
Elevation: < 2500 m.
Bioregional distribution: California Floristic Province, Modoc Plateau
Distribution outside California: to Washington, Montana, Utah, nw Baja California; s S.America
Plants generally thinly silky-tomentoseSee the CNPS Inventory for information about endangerment and rarity.
Stems generally branched above, ± erect; central stem dominant
Leaves: longest of uppermost leaves generally 1425 mm, generally 36 X > wide
Inflorescence: largest head 914 mm, ± ovoid; receptacle deeply lobed; longest chaff scale > 3 X > wide, narrowly cylindric, wing ± 0.5 distance from base to top of scale
Disk flowers 5-lobed
Ecology: UNCOMMON. Vernal pools, flats
Elevation: 10500 m.
Bioregional distribution: Deltaic Great Central Valley, San Francisco Bay Area.Like P. elatior.