Malacothrix stebbinsii

W. S. Davis & P. H. Raven

Madroño 16: 265, fig. 2e. 1962.

Common names: Stebbins’s desertdandelion
Synonyms: Malacothrix clevelandii var. stebbinsii (W. S. Davis & P. H. Raven) Cronquist
Treatment appears in FNA Volume 19. Treatment on page 321. Mentioned on page 312.

Annuals, 5–60 cm. Stems 1–5+, ± erect, branched distally, sparsely leafy, glabrous. Cauline leaves: proximal obovate, pinnately lobed (lobes 3–5+ pairs, triangular to oblong or linear), not fleshy, ultimate margins entire or dentate, faces glabrous; distal reduced (usually with 2 lobes near bases). Calyculi of 5–8+, ovate to lanceolate bractlets, hyaline margins 0.05–0.2 mm. Involucres ± campanulate, 7–10 × 3–6 mm. Phyllaries 16–20+ in 2–3 series, lanceolate to lance-linear, hyaline margins 0.05–0.1 mm wide, faces glabrous. Receptacles not bristly. Florets 19–70; corollas usually yellow, sometimes white, 6–7 mm; outer ligules exserted 1–2 mm. Cypselae ± cylindro-fusiform, 1.7–2.3 mm, ribs extending to ca. 0.1–0.2 mm short of apices (minutely hirtellous or muriculate), ± equal (distal 0.1–0.2 mm of cypselae smooth); pappi persistent, of 8–15+, needlelike teeth plus 1 (–2) bristles. Pollen 70–100% 4-porate. 2n = 28.


Phenology: Flowering Mar–Jun.
Habitat: Gravelly soils beneath shrubs, along ditches, near streams, in sagebrush steppes, creosote bush scrublands
Elevation: 300–1300 m

Distribution

V19-489-distribution-map.gif

Ariz., Calif., Nev., N.Mex., Mexico (Sonora)

Discussion

Malacothrix stebbinsii grows in the Mojave Desert (Borrego area, California) and the Sonoran Desert (Santa Catalina, Mazatzal, Baboquivari, and Santa Rita mountains, and elsewhere in Arizona).

Selected References

None.

Lower Taxa

None.

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

... more about "Malacothrix stebbinsii"
obtuse;acute or acuminate +
scarious +
ovate +  and lanceolate +
corymbiform +  and paniculiform +
indeterminate +  and determinate +
W. S. Davis +
W. S. Davis & P. H. Raven +
decurrent +
compound +  and simple +
lanceolate;obovate oblanceolate or spatulate +
tuberculate +, rugose +, muricate +  and smooth +
ovate;lanceolate +
subequal +  and unequal +
filiform +
Stebbins’s desertdandelion +
zygomorphic +, actinomorphic +  and (3-)5-merous +
white +  and yellow +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
crenate +
stramineous +  and brown or purplish brown +
cylindro-fusiform +
Ariz. +, Calif. +, Nev. +, N.Mex. +  and Mexico (Sonora) +
300–1300 m +
winged +  and beaked +
dispersed +
Gravelly soils beneath shrubs, along ditches, near streams, in sagebrush steppes, creosote bush scrublands +
indeterminate +
each +  and sessile +
0.7 cm7 mm <br />0.007 m <br /> (1 cm10 mm <br />0.01 m <br />) +
campanulate +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
cauline +  and basal +
divided +, lobed +  and dentate +
0.05mm +  and 0.1mm +
0.1 cm1 mm <br />0.001 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
2-carpellate +
persistent +
Flowering Mar–Jun. +
connate +  and distinct +
16 +  and 20 +
subequal +  and unequal +
flat;more or less convex +
crenate +
exalbuminous +
leafy +  and branched +
1 +  and 5 +
appendaged +  and truncate +
papillate +
Malacothrix clevelandii var. stebbinsii +
Malacothrix stebbinsii +
Malacothrix +
species +
70 cm700 mm <br />0.7 m <br /> (200 cm2,000 mm <br />2 m <br />) +
5 cm50 mm <br />0.05 m <br /> (60 cm600 mm <br />0.6 m <br />) +
shrub +  and subshrub +