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    THIS PAGE IS NO LONGER UPDATED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.

MICROPUS

James D. Morefield

Annual, generally grayish, cobwebby to tomentose
Stems 1–several, erect; central axis dominant
Leaves simple, alternate (ours), ± sessile, narrowly oblanceolate to elliptic (ours), entire
Inflorescence: heads disciform, ± sessile, solitary or in groups of 2–5; bracts like leaves; phyllaries 4–6, equal, obovate, rounded, scarious, persistent; receptacle chaffy; chaff scales subtending the pistillate flowers (pistillate chaff) > phyllaries, each enclosing a flower, falling with a fruit, bulged out and up, ± compressed side-to-side, ± thickened, hard (at least in part), ± woolly, tip ± offset to inner edge, scarious-winged; chaff scales subtending disk flowers (disk chaff) 0 or reduced, open or folded, glabrous, scarious
Pistillate flowers 4–8(12) in 1(2) series; corollas tubular
Disk flowers staminate, 2–5; ovary vestigial
Fruit obovate, bulged out and up, compressed side-to-side, smooth; style ± offset to inner edge; pappus 0; disk pappus 0 or of 1–5 smooth, deciduous bristles, included
Species in genus: 5 species: CA-FP, Medit
Etymology: (Greek: small foot)
Reference: [Holub 1976 Flora Europaea 4:126]
Ongoing research may show CA species fit best in Eur Bombycilaena , a conclusion compatible with this generic description.

Native

M. amphibolus A. Gray

MOUNT DIABLO COTTONWEED


Inflorescence: heads 3.5–5 mm, ± spheric; receptacle 1.2–1.8 X > wide; pistillate chaff scales 2–3 mm, thick and hard near midvein, tip projected inward from near top of scale, ± flat to concave, wing prominent, ovate, not withering; disk chaff present
Pistillate flowers 8–12 in 2 series
Disk flowers 1.2–1.9 mm, 4-lobed
Fruit 1–1.5 mm; pappus bristles of disk fruit 1–5, 1.7–2 mm
Ecology: UNCOMMON. Bare, grassy, or rocky slopes
Elevation: 50–800 m.
Bioregional distribution: s North Coast Ranges, San Francisco Bay Area, s Outer South Coast Ranges (Santa Barbara Co.), rare in n Sierra Nevada Foothills
Synonyms: Stylocline a. (A. Gray) J.T. Howell
Distinct but ± intermediate between M. californicus and Stylocline species; perhaps of hybrid origin.

previous taxon | next taxon
bioregional map for MICROPUS%20amphibolus being generated
 


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