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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.

 

GUTIERREZIA SNAKEWEED, MATCHWEED

David J. Keil & Meredith A. Lane


Subshrub (in California), <= 1.5 m, appearing glabrous. Stem: 1–many from base, erect or ascending, branched distally, ± striate, gummy-resinous, minutely scabrous, yellow to tan or gray; older bark generally fibrous. Leaf: alternate, sometimes in axillary clusters, entire, gland-dotted, gummy-resinous, glabrous or minutely scabrous, dark gray-green. Inflorescence: heads radiate, generally many in ± open cyme-like clusters, 1 or in short-peduncled clusters at tips of inflorescence branches; involucre ± cylindric or narrowly to widely obconic; phyllaries graduated in 3–4 series, straw-colored, tips green; receptacle flat to conic, epaleate, minutely hairy. Ray flower: 1–13; corolla yellow, ray often inconspicuous. Disk flower: 1–13 (in California), bisexual or staminate; corolla yellow, club- or narrowly funnel-shaped, lobes short, recurved; style appendages lanceolate. Fruit: narrowly obconic, 5–8-veined, light tan, with ± white appressed hairs; pappus of 1–2 series of finely toothed, white or ± yellow scales generally 1/2 fruit length (in California) or much reduced.
28 species: western North America, South America. (Gutiérrez, surname of a noble Spanish family) TOXIC to livestock, fresh or dried in hay. [Nesom 2006 FNANM 20:88–94]
Unabridged references: [Lane 1985 Syst Bot 10:7–28]

Key to Gutierrezia

1. Involucre cylindric; phyllaries 4–6; ray flowers 1–2 ..... G. microcephala

1' Involucre cylindric to obconic or bell-shaped; phyllaries 8–21; ray flowers 2–13

2. Ray flowers 4–13; disk flowers 4–13; total flowers 8–20; heads generally 1 at 2° inflorescence tips ..... G. californica

2' Ray flowers 2–8; disk flowers 2–9; total flowers 6–14; heads generally in clusters of 2–5 at 2° inflorescence tips ..... G. sarothrae

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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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