The largest family of flowering plants , the Compositae (Asteraceae), comprising about 1,100 genera and more than 20,000 species and characterized by many small flowers arranged in a head looking like a single flower and subtended by an involucre of bracts. A head may consist of both ray flowers and disk flowers, as in the sunflower, of disk flowers only, as in the burdock, or of ray flowers only, as in the dandelion.
, or subshrubs
, 10-150(-200) cm (taprooted). Stems erect
, usually branched, glabrous
or papillate-scabrous to minutely hispidulous
or scabro-hirtellous. Leaves basal (persistent
or absent at flowering) and cauline; alternate; sessile or petiolate
(decurrent) ; blades
to lanceolate or spatulate
entire (sometimes scabroso-ciliate), faces
glabrous or minutely hairy
, gland-dotted (sometimes obscurely), resinous
. Heads radiate
, borne singly or (3-6) in clusters
. Involucres cylindric
, (2-11.5 ×) 0.8-7.5 mm.
Phyllaries 4-40 in 2-4 series (stramineous
), 1- or 3-nerved, (sometimes strongly convex
to lanceolate, unequal, bases
white-indurate, margins narrowly scarious
faces glabrous or sparsely hispidulous or hirtellous. Receptacles flat to conic, pitted
1-seriate, swollen, apically hooked
), epaleate. Ray florets 1-30, pistillate
; corollas yellow or white (laminae
). Disc florets 1-150, bisexual
, fertile, sometimes functionally staminate
; corollas yellow or white, tubes
shorter than funnelform
5, erect, short-deltate; style-branch appendages
linear-lanceolate. Cypselae (light tan to purplish black) clavate
or cylindric, not compressed
, 5-8-nerved, hairy (glabrous in G. wrightii; hairs white, usually arising primarily from between ribs
, appearing to occur in longitudinal
, usually obscuring faces, apices acute or blunt
slightly divergent, or clavate to bulbous) ; pappi persistent or readily falling, coroniform
or of 5-10 whitish, irregular, sometimes ± connate
, often erose-margined, scales
in 1-2 series (usually longer
in discs than rays). x = 4.
Species 28: w North America, w South America.
Amphiachyris sometimes has been placed within Gutierrezia; it was treated as distinct by M. A. Lane (1982). The monotypic genus Thurovia from southeast Texas was included in Gutierrezia by Lane; recent molecular data support its status as a separate genus. Evidence from Y. Suh and B . B. Simpson (1990) suggested that Amphiachyris and Thurovia form the sister group to Gutierrezia. The taxonomic history of Gutierrezia also has been intertwined with species of Xanthocephalum, a genus superficially similar to Gutierrezia but more closely related to Grindelia and Isocoma.
Gutierrezia is recognized by its taprooted habit, gland-dotted leaves, small heads , receptacles with fimbriate pit borders , funnelform disc corollas, clavate-hairy cypselae, pappi coroniform or of scales, and base chromosome number of x = 4. Polyploidy is common but of little taxonomic significance; polyploids of different levels tend to be scattered through the range of a species, and populations often comprise mixtures of individuals of different euploid levels (M. A. Lane 1985).
- Whittaker & Margulis,1978
- Haeckel, 1866
- Cavalier-Smith, 1981
- Sinnott, 1935 ex Cavalier-Smith, 1998
- Vascular Plants
- Brongniart, 1843
- Takhtajan, 1967
- Takhtajan Ex Reveal, 1992
- Lindley, 1833
- Family: Compositae () - Giseke, 1792, nom. cons., nom. alt.
- Order: Asterales () - Lindley, 1833
- Superorder: Campanulanae () - Takhtajan Ex Reveal, 1992
- Subclass: Asteridae () - Takhtajan, 1967
- Class: Spermatopsida () - Brongniart, 1843
- Subphylum: Euphyllophytina ()
- Phylum: Tracheophyta () - Sinnott, 1935 ex Cavalier-Smith, 1998 - Vascular Plants
- Subkingdom: Viridaeplantae () - Cavalier-Smith, 1981
- Kingdom: Plantae () - Haeckel, 1866 - Plants
Members of the genus Gutierrezia
ZipcodeZoo has pages for 12 species, subspecies, varieties, forms, and cultivars in this genus:
G. arizonica (Arizona Snakeweed) · G. californica (Bay Matchweed) · G. microcephala (Small-Head Snakeweed) · G. petradoria (Goldenrod Snakeweed) · G. sarothrae (Broom Snakeweed) · G. serotina (Late Snakeweed) · G. sphaerocephala (Annual Snakeweed) · G. texana (Kindling Weed) · G. texana (DC.) Torr. and Gray var. glutinosa (S.Schauer) M.A.Lane (Sticky Snakeweed) · G. texana var. glutinosa (Sticky Snakeweed) · G. texana var. texana (Texas Snakeweed) · G. wrightii (Wright's Snakeweed)
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- Lane, M. A. 1985. Taxonomy of Gutierrezia (Compositae: Astereae) in North America. Syst. Bot. 10: 7-28.
- Solbrig, O. T. 1960b. Cytotaxonomic and evolutionary studies in the North American species of Gutierrezia. Contr. Gray Herb. 188: 1-63.
- Solbrig, O. T. 1964. Infraspecific variation in the Gutierrezia sarothrae complex (Compositae-Astereae). Contr. Gray Herb. 193: 67-115.
- Solbrig, O. T. 1965. The California species of Gutierrezia. Madroño 18: 75-84.
- Solbrig, O. T. 1970. The phylogeny of Gutierrezia: An eclectic approach. Brittonia 22: 217-229.
- Brands, S.J. (comp.) 1989-present. The Taxonomicon. Universal Taxonomic Services, Zwaag, The Netherlands. Accessed January 10, 2012.