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), Mexico (Chihuahua), Mexico (Coahuila), Mexico (Durango), Mexico (Nuevo León), Mexico (San Luis Potosí), Mexico (Sonora), Mexico (Tamaulipas), Mexico (Veracruz), Mexico (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.

"[" is not declared as a valid unit of measurement for this property."]" is not declared as a valid unit of measurement for this property.

... more about "Gutierrezia microcephala"
32 +, 24 +, 16 +  and 8 +
hirtellous +, hispidulous +  and glabrous +
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
spiciform +, racemiform +, paniculiform +  and corymbiform +
indeterminate +  and determinate +
flat-topped +
Guy L. Nesom +
(de Candolle) A. Gray +
decurrent +
white-indurate +
Brachyris microcephala +
compound +  and simple +
linear;lanceolate or spatulate +
rugulose +  and muricate +
barbellulate +  and barbellate +
filiform +  and narrowly oblanceolate or lanceolate +
Small-head snakeweed +
not 2-lipped +  and actinomorphic +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
0.18 cm1.8 mm <br />0.0018 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
not compressed +, cylindric +  and clavate +
fertile +  and bisexual +
fertile +  and bisexual +
Ariz. +, Calif. +, Colo. +, Nev. +, N.Mex. +, Tex. +, Utah +, Mexico (Baja California) +, Mexico (Chihuahua) +, Mexico (Coahuila) +, Mexico (Durango) +, Mexico (Nuevo León) +, Mexico (San Luis Potosí) +, Mexico (Sonora) +, Mexico (Tamaulipas) +, Mexico (Veracruz) +  and Mexico (Zacatecas) +
800–2500 m +
resinous +
gland-dotted +
strigoso-sericeous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Grasslands, chaparral, oak or oak-pine woodlands, usually over gravelly or rocky limestone or gypsum substrates, dunes +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
petiolate +  and sessile +
proximal +  and basal +
short-deltate +
2-carpellate +
erose-margined +
persistent +
of 5-10 whitish +  and coroniform +
Flowering (Jun–)Jul–Dec(–Feb). +
3-nerved +  and 1-nerved +
ovate +  and lanceolate +
Mem. Amer. Acad. Arts, n. s. +
bearing subulate enations +, hairy +  and bristly +
lanceolate-oblong +
exalbuminous +
erect +  and ascending +
appendaged +  and truncate +
papillate +  and smooth +
Gutierrezia sarothrae var. microcephala +  and Xanthocephalum microcephalum +
Gutierrezia microcephala +
Gutierrezia +
species +
150 cm1,500 mm <br />1.5 m <br /> (200 cm2,000 mm <br />2 m <br />) +
perennial +  and annual +
10 cm100 mm <br />0.1 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +