BOERHAVIA COULTERIVAR. COULTERI (NY CT AGIN ACEE), NEW TO CALIFORNIA
Department of Biology, MSC 3AF
New Mexico State University
Las duces, New Mexico 88003
Boerhavia coulteri var. coulter 7 is reported as new to California. The taxon was a major
component among a dense population of two other boerhavias, B. coulteri var. palmeri and B.
triquetra var. intermedia, that occurred for several kilometers along Interstate Highway 15 contiguous
with the Nevada state line at Primm. The var. coulteri is rather weedy and seems to be spreading
from its original range in the Sonoran Desert.
KEY WORDS: Nyctaginaceae, Boerhavia, San Bernardino Co., California, new record
While returning to New Mexico from a family visit to California I noted a dense stand of
robust plants of Boerhavia at the edge of the pavement of Interstate Highway 15 on the filled roadbed
of the highway that crosses the dry bed of Ivanpah Lake. The population extended for several
kilometers west of the Nevada state line. The most westward plants noted were of Boerhavia coulteri
var. coulteri, easily seen to be erect plants with bright green stems. Slightly eastward it was apparent
at least one other Boerhavia with spreading, purplish stems occurred with the var. coulteri. My wife
and ! turned the car around in Primm and went bade, quickly stopped on this very busy interstate,
took location notes, hastily grabbed samples of each of the species, stuffed them in the back seat, and
returned to a vacant parking lot in Primm to press them. Among the three taxa collected was the var.
coulteri, a taxon not included in Murdock's excellent treatment of the Nyctaginaceae (Murdock 2012)
in the recently revised Jepson Manual. Searches of relevant herbaria websites also reveal no
specimens of the taxon collected in California. To my knowledge, this is the first report for
California of B. coulteri var. coulteri, a Sonoran Desert taxon that seems to be spreading into
surrounding areas as a weed in cities and along roadsides.
The record is as follows: Boerhavia coulteri var. coulteri. California. S an Bernardino Co. :
IH-15 on highway fill across Ivanpah Lake bed, 3 km SW of Nevada state line at Primm, 35°34.876',
1 1 5°24. 130*; elev. 800 m, road shoulder on S side of interstate in area otherwise nearly barren of
vegetation; plants part of a dense, robust, population of 3 taxa of boerhavias intertangied among one
another, the population ca. 4 km long, and 1-2 m wide; with B. triquetra var. intermedia (14458) and
B. coulteri var. palmeri (14459), also with scattered Kallstroemia grandiflora, 12 Sept. 2012, R
Spellenberg andN. Zucker 14459 (RSA, to be deposited). Figure 1 shows all three taxa.
The three taxa are distinguished by the characters used in the Nyctaginaceae treatment for the
Flora of North America (Spellenberg 2003). At this site they were also distinguished as follows :
Boerhavia coulteri (Hook, f.) S. Wats. var. coulteri - stems bright green, strongly ascending to
erect; perianth pale pink; plants well into fruit maturation.
Boerhavia coulteri (Hook, f) S. Wats. var. palmeri (S. Wats.) Spellenb. - stems purplish, widely
spreading to ascending; perianth pink; plants just beginning fruit maturation.
Boerhavia triquetra S. Wats. var. intermedia (M.E. Jones) Spellenb. - stems green, stems
spreading to erect; perianth pale pink; plants well into fruit maturation.
Figure 1. Photos of Boerhavia from the site at Ivanpah Lake, California, from specimens cited. A. Boerhavk
coulteri var. coulteri; B. B. coulleri var. palmeri; C.B. triquetra var. intermedia. Fruits of A and Bare 3.1 m
long; fruits of C are 2.5 mm long.
The short duration of the stop along this busy freeway did not allow a search for
intergradation between the two varieties of Boerhavia coulteri. As noted in Spellenberg (2003),
intergradient plants are occasionally encountered in Arizona, In this population the fruits on the
specimen of var. palmeri thai was collected are larger than indicated in Spellenberg (2003), about the
same size as fruits of var. coulteri in this population. There was also little habitat separation noted
between the taxa, with the exception that the var. coulteri was the first noted at the western end of the
population, the other two species occurring eastward with B. coulteri var. coulteri in the mix. The
phenological and morphological differences noted among these sympatric varieties suggest that
species level classification may be preferable to varietal level classification within B. coulteri, but
that decision should await careful studies among populations of both varieties.
Murdock, A. 2012. Nyctaginaceae. Pp. 916-922, in B.G. Baldwin (convening editor). The Jepson
Manual, 2 nd . ed. Univ. of California Press, Berkeley.
Spellenberg, R.W. 2003. Boerhavia. Pp. 17-28, in Flora of North America Editorial Committee,
Flora of North America, Vol. 4. Oxford Univ. Press, New York,