Gutierrezia microcephala

(de Candolle) A. Gray

Mem. Amer. Acad. Arts, n. s. 4: 74. 1849.

Common names: Small-head snakeweed
Basionym: Brachyris microcephala de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 313. 1836
Synonyms: Gutierrezia sarothrae var. microcephala (de Candolle) L. D. Benson Xanthocephalum microcephalum (de Candolle) Shinners
Treatment appears in FNA Volume 20. Treatment on page 92. Mentioned on page 90.

Subshrubs, 20–140 cm. Stems glabrous or minutely hispidulous. Leaves: basal and proximal absent at flowering; cauline blades 1-nerved, linear or filiform to narrowly oblanceolate or lanceolate, 0.5–2.2(–4) mm wide, little reduced distally. Heads (2–6, sessile to subsessile, in compact glomerules) in flat-topped arrays. Involucres cylindric, 1–1.5 mm diam. Phyllary apices flat. Ray florets 1(–2; each enclosed by conduplicate inner phyllary); corollas yellow, (1.5–)2–3.5 mm. Disc florets 1, sometimes 2 (functionally staminate; corollas broadly obdeltate-funnelform, throats widely flaring, lobes 1/3 corolla lengths, recurved-coiling). Cypselae 1–1.8(–2.5) mm, faces densely strigoso-sericeous; pappi (rays, readily falling) of 1 series of narrowly lanceolate-oblong scales. 2n = 8, 16, 24, 32.


Phenology: Flowering (Jun–)Jul–Dec(–Feb).
Habitat: Grasslands, chaparral, oak or oak-pine woodlands, usually over gravelly or rocky limestone or gypsum substrates, dunes
Elevation: 800–2500 m

Distribution

V20-177-distribution-map.gif

Ariz., Calif., Colo., Nev., N.Mex., Tex., Utah, Mexico (Baja California, Chihuahua, Coahuila, Durango, Nuevo León, San Luis Potosí, Sonora, Tamaulipas, Veracruz, Zacatecas).

Discussion

Gutierrezia microcephala is recognized by its perennial habit and its small, tightly clustered heads, each with 4–8 phyllaries and 1(–2) ray and disc florets. Each ray floret is enclosed by a conduplicate inner phyllary. Forms of G. sarothrae with few florets in each head can be distinguished by their bisexual and fertile disc florets and tubular-funnelform disc corollas.

Selected References

None.

Lower Taxa

None.
... more about "Gutierrezia microcephala"
Guy L. Nesom +
(de Candolle) A. Gray +
Brachyris microcephala +
Small-head snakeweed +
Ariz. +, Calif. +, Colo. +, Nev. +, N.Mex. +, Tex. +, Utah +, Mexico (Baja California +, Chihuahua +, Coahuila +, Durango +, Nuevo León +, San Luis Potosí +, Sonora +, Tamaulipas +, Veracruz +  and Zacatecas). +
800–2500 m +
Grasslands, chaparral, oak or oak-pine woodlands, usually over gravelly or rocky limestone or gypsum substrates, dunes +
Flowering (Jun–)Jul–Dec(–Feb). +
Mem. Amer. Acad. Arts, n. s. +
Gutierrezia sarothrae var. microcephala +  and Xanthocephalum microcephalum +
Gutierrezia microcephala +
Gutierrezia +
species +