Stebbinsoseris heterocarpa

(Nuttall) K. L. Chambers

Amer. J. Bot. 78: 1024. 1991.

Common names: Grassland or derived silverpuffs
Illustrated
Basionym: Uropappus heterocarpus Nuttall Trans. Amer. Philos. Soc., n. s. 7: 425. 1841
Synonyms: Microseris heterocarpa (Nuttall) K. L. Chambers
Treatment appears in FNA Volume 19. Treatment on page 347.

Peduncles 5–60 cm. Involucres 6–30 mm. Florets 10–125; corollas yellow or white. Cypselae gray, straw-colored, brown, or violet (dark purplish in southwest California), narrowly truncate-fusiform to columnar, 4.5–12 mm, each filled by embryo or distal 0.5–3 mm vacant and more slender than proximal part, apices slightly widened at bases of pappi; pappi 7–19 mm, scale bodies 4–11 mm, faces usually glabrous, rarely villous, aristae 3–8 mm. 2n = 36.


Phenology: Flowering Apr–Jun.
Habitat: Clay, gravelly, or rocky soils, open flats and hillsides, grasslands, oak woodlands, chaparral, coastal scrub, desert (rarely), roadsides
Elevation: 0–1000 m

Distribution

V19-542-distribution-map.gif

Ariz., Calif., Mexico (Baja California)

Discussion

Stebbinsoseris heterocarpa is widespread in cismontane California and disjunct to Gila and Yavapai counties, Arizona. Variation in enzymatic restriction sites in its chloroplast DNA and nuclear rDNA (R. S. Wallace and R. K. Jansen 1995) indicates that S. heterocarpa has arisen independently three or more times from hybrids of Microseris douglasii × Uropappus lindleyi. Reflecting this multiple origin, the species is more variable in pappi and cypsela size, color, and shape than S. decipiens, from which it is largely allopatric. Because M. douglasii subsp. tenella and M. bigelovii intergrade in some coastal areas, forms of S. heterocarpa having such hybrids as their maternal parent would be difficult to distinguish from S. decipiens (K. L. Chambers 1955; U. Lohwasser and F. R. Blattner 2004).

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

scarious +
widened +
ovate +  and lanceolate +
0.3 cm3 mm <br />0.003 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
paniculiform +  and corymbiform +
indeterminate +  and determinate +
Kenton L. Chambers +
(Nuttall) K. L. Chambers +
decurrent +
Uropappus heterocarpus +
compound +  and simple +
linear;narrowly oblanceolate +
tuberculate +, rugose +, muricate +  and smooth +
ovate;lanceolate +
filiform +
Grassland or derived silverpuffs +
zygomorphic +, actinomorphic +  and (3-)5-merous +
white +  and yellow +
violet +, brown +, straw-colored +  and gray +
narrowly truncate-fusiform +  and columnar +
more slender +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
Ariz. +, Calif. +  and Mexico (Baja California) +
0–1000 m +
villous +  and glabrous +
winged +  and beaked +
dispersed +
Clay, gravelly, or rocky soils, open flats and hillsides, grasslands, oak woodlands, chaparral, coastal scrub, desert (rarely), roadsides +
indeterminate +
each +  and sessile +
0.5 cm5 mm <br />0.005 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
campanulate +
0.6 cm6 mm <br />0.006 m <br /> (3 cm30 mm <br />0.03 m <br />) +
cauline +  and basal +
irregularly dentate or lobed +  and entire +
divided +, lobed +  and dentate +
2-carpellate +
white +, brownish +  and yellowish +
persistent +
0.7 cm7 mm <br />0.007 m <br /> (1.9 cm19 mm <br />0.019 m <br />) +
5 cm50 mm <br />0.05 m <br /> (60 cm600 mm <br />0.6 m <br />) +
Flowering Apr–Jun. +
connate +  and distinct +
5 +  and 18 +
Amer. J. Bot. +
flat;convex +
spiculate +  and scabrellous +
0.4 cm4 mm <br />0.004 m <br /> (1.1 cm11 mm <br />0.011 m <br />) +
aristate +
exalbuminous +
Illustrated +
appendaged +  and truncate +
papillate +
Microseris heterocarpa +
Stebbinsoseris heterocarpa +
Stebbinsoseris +
species +
1 cm10 mm <br />0.01 m <br /> (10 cm100 mm <br />0.1 m <br />) +
shrub +  and subshrub +