Camissonia bistorta (Nutt. ex Torr. & A.Gray) P.H.Raven
-
Authority
Raven, Peter H. 1969. A revision of the genus Camissonia (Onagraceae). Contr. U. S. Natl. Herb. 37: 161-396.
-
Family
Onagraceae
-
Scientific Name
-
Type
Type: San Diego, San Diego County, California, April-May 1836, T. Nuttall (NY; isotypes, BM, K, GH, PH).
-
Description
Description - Annual, or rarely a short-lived perennial, with one to several ascending or several spreading, decumbent stems radiating from a central rosette, these to 0.8 mm. long, with a conspicuously exfoliating pale rhytidome. Plants strigose or more commonly villous. Leaves very narrowly elliptic iti the basal rosette to narrowly lanceolate or lanceolate on the stems and in the inflorescence, rarely all linear, 1.2-12 cm. long, 0.15-1 .5 cm. wide, denticulate, but often only sparsely and inconspicuously so. the apex acute, the base narrowly cuneate (in the basal rosette) to cuneate or subcordate; petioles to 4 cm. long in the basal rosette, the upper leaves usually subsessile. Inflorescence with two types of trichomes, short-erect and long-villous. Hypanthium Annual, or rarely a short-lived perennial, with one to several ascending or several spreading, decumbent stems radiating from a central rosette, these to 0.8 mm. long, with a conspicuously exfoliating pale rhytidome. Plants strigose or more commonly villous. Leaves very narrowly elliptic iti the basal rosette to narrowly lanceolate or lanceolate on the stems and in the inflorescence, rarely all linear, 1.2-12 cm. long, 0.15-1 .5 cm. wide, denticulate, but often only sparsely and inconspicuously so. the apex acute, the base narrowly cuneate (in the basal rosette) to cuneate or subcordate; petioles to 4 cm. long in the basal rosette, the upper leaves usually subsessile. Inflorescence with two types of trichomes, short-erect and long-villous. Hypanthium 2-5 (-7.5) mm. long, 1.5-4 mm. across at the summit, glabrous to pubescent in lower portions within, often with prominent red dots near the summit within. Sepals (2.3-) 5 S (-11) mm. long, (0.8-) 1-2 mm. wide, reflexed in pairs. Petals (4.2-) 7-15 mm. long, (2.5-) 6.5-12 (-16) mm. wide, each petal almost always with a bright red spot (rarely two) near the base. Filaments of the episepalous stamens (1-) 1.5-3.5 mm. long, those of the epipetalous ones (0.5-) 1-2.5 mm. long; anthers (0.5-) 1.3-2 (-2.5) mm. long. Style (5.5-) 7-12 mm. long, usually glabrous but occasionally pubescent near the base; stigma (0.7-) 1-1.8 mm. in diameter, held well above the anthers at anthesis. Capsule 1.2-4 cm. long, 1.5-2.5 mm. thick, more or less quadrangular in transection, straight or somewhat contorted. Seeds 0.9-1 mm. long, 0.3-0.55 mm. thick. Gametic chromosome number, n=7. Self-incompatible.
-
Discussion
The chromosome number has been determined from 29 individuals derived from 22 populations scattered throughout the range of the species (see Appendix). Populations from 6.5 miles northeast of San Juan Capistrano, Orange County, California, R18782 (8 individuals); lower edge of Cleveland National Forest, just above San Juan Campground, Santa Ana Mountains, Orange County, California, R18783 (6 individuals); Point Dume, Los Angeles County (2 individuals); and Claremont, Los Angeles County, California (10 individuals), were grown in the experimental garden and found to be self-incompatible. In addition, the Claremont strain was grown by Hagen (Indiana Univ. Publ. Sci. Ser. 16: 309. 1950) who also found it to be self-incompatible. Several species of large bees of the genus Andrena subgenera Diandrena and Onagrandrena are frequent oligolectic visitors to the flowers of Camissonia bistorta soon after they open in the early morning and doubtless are the most important agents in effecting cross-pollination in this species. Camissonia bistorta may well be an annual derivative of populations similar to the self-incompatible ones referred to C. cheiranthifolia subsp. cheiranthifolia, although the reverse hypothesis cannot be excluded at present. Depauperate individuals of this species, found in dry years or unfavorable sites, often have relatively small flowers, as do plants at the end of their flowering period. The stigma is, however, consistently held above the anthers, and such plants can thereby easily be separated from the numerous related autogamous species in sect, Holostigma. This species occurs sympatrically with C. lewisii, and a single obvious F1 hybrid between the two species has been collected at Playa del Rev, Los Angeles County, California, Wedberg 272 (herb. San Diego State College). This plant had about 23 percent stainable pollen and apparently full seed-set; at meiosis it formed variable configurations of chromosomes, the maximum observed in 14 cells being 1 pair, 1 ring of 4, 1 chain of 3, and 5 univalents (H. L. Wedberg, pers. comm.). Camissonia bistorta also occurs adjacent to and hybridizes extensively with C. cheiranthifolia subsp. suffruticosa, as explained in the section dealing with that taxon. It has likewise been observed growing sympatrically with C. mwrantha, C. hirtella, C. ignota, C. intermedia, C. confusa, and C. robusta, but hybrids between these predominantly autogamous species and C. bistorta have not been found. Camissonia bistorta is probably relatively similar to the populations ancestral to at least some of the autogamous taxa in this section, the most obvious relationship being that with C. lewisii. In his original treatment of this species (Bot. Gaz. 85: 266-267. 1928), Munz included two varieties in addition to the typical one. The first of these, Oenothera bistorta var. veitchiana Hook., was applied to inland populations with relatively slender, long, and straight capsides which differed in these respects from the series of coastal populations, including the type of the species, which have thicker, shorter, usually coiled capsules. These two entities intergrade so broadly that it does not appear useful to segregate them taxonomically. The other variety recognized by Munz, 0. bistorta var. hallii (Davids.) Jeps., intergrades completely with the entity designated by Munz 0. hirta var. exfoliata (A. Nels.) Munz and is here treated, together with that taxon, as the species Camissonia pallida (Abrams) Raven. Camissonia pallida and C. bistorta do not occur together, as far as I know, and, although both entities are diploid (n=7), there appears to be no evidence for morphological intergradation or even of overlapping patterns of variation. The report of Camissonia bistorta from Santa Catalina Island, California (Millspaugh & Nuttall, Field Mus. Publ. Bot. 5: 183. 1923; as Sphaerostigma bistortum) is based on misidentified specimens of C. robusta and C. californica, which I have seen.