Cottontop :

Slender Cottonweed, Q-tips
Micropus californicus var. californicus
NATIVE

Description (Jepson, PlantID.net)

Eudicotyledon
- Eudicots are a major lineage of flowering plants; see family for general characteristics
Sunflower Family (Asteraceae)
Annual herb
- Erect, with a central dominant stem
- Entire plant gray-green, with short, soft, woolly hairs (tomentose) or cobwebbed
Leaves
- Slender, slightly rounded, and tapering to base
Flowers
- Inflorescence (flower arrangement) of 1-5 densely-clustered flowerheads
- Each disciform flowerhead (see Sunflower family) with minute, white, unisexual flowers
  - 4-12 female (pistillate) peripheral flowers, obscured by densely-woolly chaff scales (paleae)
  - 2-5 functionally male (staminate) central disk flowers
- Ovary inferior (below the attachment of other flower parts)
Fruit is an achene (a single-seeded, dry fruit that does not split open), more specifically called a cypsela because of the inferior position of the ovary, without pappus (modified sepals, outer flower parts)
Height to 4 in. (Corelli 2004)

Distribution

Native to California
- Grows in thin soils in a variety of habitats, including grasslands, woodlands, disturbed areas, and chaparral
- See Calflora for statewide observations of this plant
Outside California, grows from western Oregon to northwest Baja California, Mexico
Grows at elevations to 5,250 ft.

Uses (San Mateo County Parks prohibits removal of any natural material)

Wildlife
- Secondary food source (host) for the larvae of the painted lady butterfly (Vanessa cardui) (Caldwell 2014)

Name Derivation

Micropus (my-KRO-pus) – from the Greek micros, “small,” and pous, “foot,” possibly referring to the tiny flowers
Cottontop – referring to the flowers, which resemble cotton-balls

Notes

Woolly hairs reflect harsh sun rays and help retain humidity
Edgewood’s cottontop is classified as a variety
- Variety indicates a population with small morphological variations, e.g. color, seen throughout the geographic range of the species; interbreeding is possible
- Subspecies indicates a geographically-separated population with distinct morphological characteristics; when not isolated, interbreeding is possible
- In practice, botanists have not consistently applied these ranks

ID Tips

May be confused with the equally-small and unassuming California plantain (Plantago erecta) which often grows with cottontop in the same habitat
- Cottontop’s flowers are hidden in its cobwebby hairs
- California plantain’s flowers are visible

At Edgewood

Specific References

Breckling, B. 2008. Spring Wildflowers of Henry W. Coe State Park and the Inland San Francisco Bay Area. Pine Ridge Association.

Prigge, B.A., and A.C. Gibson. 2013. Micropus californicus var. californicus. A Naturalist’s Flora of the Santa Monica Mountains and Simi Hills, California. Web version, hosted at Wildflowers of the Santa Monica Mountains National Recreation Area. United States Department of Interior, National Park Service.

General References

Calflora Database. 2014. Berkeley, California.

Calscape. 2018. California Native Plant Society.

Corelli, T. 2004. Flowering Plants of Edgewood Natural Preserve (2nd. ed.). Monocot Press, Half Moon Bay, California.

Elpel, T.J. 2013. Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, Pony, Montana.

Harris, J.G., and M.W. Harris. 2013. Plant Identification Terminology: An Illustrated Glossary. Spring Lake Publishing, Spring Lake, Utah.

Keator, G. 2009. California Plant Families. University of California Press, Berkeley and Los Angeles, California.

Regents of the University of California. Jepson eFlora. Jepson Herbarium. University of California, Berkeley.