Chamaesyce capitellata (Engelm.) Millsp.
Family: Euphorbiaceae
Synomnys: Chamaesyce pycnanthema (Engelm.) Millsp.;
Euphorbia capitellata
Engelm.;
Euphorbia pycnanthema Engelm.;
Euphorbia rusbyi Greene;
Euphorbia geminiloba Millsp.
Distribution: The type is from Arizona/Sonora border at
San Bernardo (by Wright). Arizona, western Texas, Chihuahua, Coahuila,
Sonora, Sinaloa, Lower California (Wheeler 1941).; Brewster county
(Big Bend area), Texas (Correll & Johnston 1979); northwestern
Mexico from Coahuila to the Baja California penninsula and Durango,
and the southwestern United States from Arizona to Texas (Steinmann
& Felger 1997).
Habitat: Hillsides, washes, arid plains (Shreve & Wiggins
1964); Chihuahuan Desert (as
E. pycnanthema; Correll &
Johnston 1979); Sonoran desert scrub, grassland, thorn scrub, and
tropical deciduous forest (Steinmann & Felger 1997).
Plants Seen or Cited: No records in New Mexico Natural Heritage Program Database. Two specimens
at UNM.
1. E.F. Castetter. 20 August 1955. Hidalgo county, New Mexico. Winkelman's
Well, Little Hatchet Mountains.
2. C.B. Carter. 30 August 1936. Pima county, Arizona. North Pima
Canyon, Tucson.
Discussion: As the several synonyms indicate, this species
is quite polymorphic within its broad range in the Chihuahuan
and Sonoran Deserts. It was not listed in Wooton & Standley
(1915). Although this plant may be rare in New Mexico, it is common
and widespread outside of the state. I recommend that it should
not be given special consideration in New Mexico, and that it
should remain on L4.
Literature cited:
Correll, D.S. and M.C. Johnston. 1979. Manual of the vascular
plants of Texas, second printing. The University of Texas at Dallas,
Richardson, TX. (page 975-976)
Shreve, F. and I.L. Wiggins. 1964. Vegetation and flora of the
Sonoran Desert. Two volumes. Stanford University Press. (pg. 823-824)
Steinmann, V.W. and R.S. Felger. 1997. The Euphorbiaceae of Sonora,
Mexico. Aliso
16(1):1-71 (page 40)
Wheeler, L.C. 1941.
Euphorbia subgenus
Chamaesyce in Canada
and United States exclusive of southern Florida. Rhodora
43:96-286
plus many plates.
Wooton, E.O. and P.S. Standley. 1915. Flora of New Mexico. Contributions
from the United States National Herbarium, Smithsonian Institution,
Government Printing Office, Washington, D.C.
Information Compiled By: David L. Bleakly, 1998
