Spearleaf [Matelea parvifolia (Torr.) Woods]

Spearleaf [Matelea parvifolia (Torr.) Woods]

Listing CNPS List 2 R-E-D Code 3-1-1

State/Federal. Status -- /C3c ASCLEPIADACEAE Mar.-May

Global Rank G5? State Rank S2.2

Distribution: San Diego County, Riverside County, San Bernardino County; Arizona; Texas; Baja California, Mexico

Habitat: Spearleaf grows in Sonoran Desert Scrub on arid plains and near arroyos. At Plum Canyon this twining herb with a woody rootstock was found at the crest of a sandy embankment. Shrub cover in the vicinity was fairly well developed. Some shade was provided by the subshrubs around which this vine-like plant was entwined.

Known Sites: A small population occurs in Plum Canyon climbing on larger shrubs. This species is easily overlooked when not in fruit (a long follicle to 5-7 cm), and its rarity is difficult to determine. An old report comes from Yaqui Well. One collection is from south of the Inner Pasture and Agua Caliente Springs, and east of the Sawtooth Mountains. East of San Diego County are desert reports from Corn Spring, Cottonwood Spring, and near Kelso. A herbarium specimen from the Chuckwalla Mountains was examined. A Data Base report from Riverside County is for Cactus Spring Trail near Horsethief Creek in the Santa Rosa Mountains; for San Bernardino County from the west end of Indian Cove Campground. Reported by Shreve and Wiggins as discontinuous from the eastern Mohave desert to western Texas; also reported in Deep Canyon in the Coachella Valley of western Riverside County. Reported by Lehr for Arizona; a herbarium specimen was seen from Tucson. Daniel and Butterwick report this species as occasional to rare in the South Mountains near Phoenix.

Sixteen specimens from Baja California are found at the herbarium of the San Diego Natural History Museum; south to 27 7' North where collected by Moran (SD 92479) on the southeastern peak of Picachos de Santa Clara.

Status: Spearleaf populations on the southern deserts are presumed stable, given the limited historical disturbances within its desert habitat. Taking into account the paucity of reported sites in the region, all populations should be protected.


Copyright May 1994 Craig H. Reiser.

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