Camissonia cheiranthifolia (Hornem. ex Spreng.) Raim. subsp. cheiranthifolia

• Authority

  Raven, Peter H. 1969. A revision of the genus Camissonia (Onagraceae). Contr. U. S. Natl. Herb. 37: 161-396.

• Family

  Onagraceae

• Scientific Name

  Camissonia cheiranthifolia (Hornem. ex Spreng.) Raim. subsp. cheiranthifolia

• Type

  Lectotype: "Ex hort. semina e California mis. Wormskiold" (C), doubtless from seed collected in the vicinity of Fort Ross, Sonoma County, or San Francisco, California. During most of the 19th century, the species was erroneously attributed to Chile, based on Sprengel's statement in the protologue; no evidence for this has ever been found, and it is assumed that Sprengel made a simple mistake (cf. Munz, Bot, Gaz. 85: 268. 1928).

• Description

  Description - Branches usually prostrate or decumbent and largely herbaceous; pubescence rarely dense and silvery. Hypanthium 2.1-4.2 (-4.8) mm. long, 1.5-3 mm. across at the summit. Sepals 4-5.6 (-6.7) mm. long, 1.3-1.9 (-2.1) mm. wide. Petals 6-11 mm. long, 5-12 mm. wide, rarely with one or two red dots near the base. Filaments of the episepalous stamens 2.8-4.5 mm. long, those of the epipetalous ones 1.5-3 mm. long. Anthers 1-1.5 mm. long. Style 6-9 mm. long; stigma surrounded by both sets of anthers which shed pollen directly onto it at anthesis, or very rarely held above the anthers. Gametic chromosome number, n = 7. Facultatively autogamous, but sometimes outcrossing; self-compatible.

• Discussion

  The gametic chromosome number of this subspecies has been determined as n=7, with no evidence of structural heterozygosity, in single individuals from eight populations throughout its range (see Appendix). Although self-pollination generally occurs in this taxon upon the closing of the flowers, some populations, especially in the San Francisco Bay area, are much visited by oligolectic bees of the genus Andrena (Onagrandrena) and are doubtless outcrossed to a large extent. Other populations, such as those around Monterey Bay and farther south, appear not to be visited often by insects of any kind and are probably predominantly self-pollinated. The flowers of subsp. cheiranthifolia generally open more tardily than those of subsp. suffruticosa, which also occupies areas where the mornings are not often foggy. This subspecies is quite variable in pubescence, and there appears to be a cline extending from the San Francisco area, where the plants are usually decumbent and greenish, to the region of Morro Bay, San Luis Obispo County, where many of the plants are more erect and silvery pubescent, resembling indiviuals of subsp. suffruticosa. Such plants may also have larger flowers than usual for subsp. cheiranthifolia but in general are not exceptional in flower size. Other variants in pubescence may occur as individual plants, mixed in populations of more usual individuals. For example, at the mouth of Hazard Canyon, San Luis Obispo County, California, Robert Hoover collected an interesting local race with large bright green but still pubescent leaves, up to 4.5 cm. long and 2 cm. wide, growing with the usual more heavily pubescent and smaller leaved plants. Occasional completely glabrous or subglabrous plants occur in populations; these individuals have been named Oenothera nitida Greene. Such plants agree with the rest of the species in chromosome number. They obviously comprise only one of the more conspicuous segregating elements in their interbreeding populations, and do not merit formal taxonomic recognition. Such glabrous plants have been collected around Monterey Bay, Monterey County, California, where they are well known; in Santa Barbara County, California, at Surf (Pierson 8308, POM, RSA) and at Jalama Beach (Smith 2848, RSA); and on Santa Rosa (East Point, Mum & Hoffmann 11744, POM) and San Miguel Islands. On San Martin Island, off the coast of Baja California, individuals of subsp. suffruticosa occur which are more prostrate than usual for that subspecies and thus resemble subsp. cheiranthijolia: Moran 10571 (ARIZ, COLO, BS, RSA, SD, UC). As these plants agree with other Baja California populations of subsp. suffruticosa in flower size and pubescence, I have regarded them as representing a maritime ecotype of that taxon. The possibility that they may in fact belong with subsp. cheiranthijolia and represent a relictual station for that more northern subspecies cannot, however, be completely ruled out at present. It does seem more likely that they have converged with it in habit on the basis of their similar ecology. Camissonia cheiranthifolia subsp. cheiranthifolia occurs sympatrically with C. micrantha, and with C. guadalupensis subsp. Clementina and locally intergrades with C. cheiranthifolia subsp. suffruticosa as discussed above.