Camissonia andina (Nutt.) P.H.Raven
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Authority
Raven, Peter H. 1969. A revision of the genus Camissonia (Onagraceae). Contr. U. S. Natl. Herb. 37: 161-396.
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Family
Onagraceae
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Scientific Name
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Type
Type: Dry plains near the Blackfoot River, Bingham or Caribou County, Idaho, 10-12 July 1834, T. Nuttall (BM; isotypes, GH, K, NY, PH).
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Description
Description - Plants finely strigulose throughout, more densely so in the inflorescence, especially on the ovaries. Branches 1-15 cm. long. Leaves very narrowly oblanceolate, 1-3 cm. long, 0.1-0.25 cm. wide, entire, acuminate at the apex, attenuate at the base. Hypanthium 0.8-2 mm. long, 0.75-1.1 mm. across at the summit, glabrous or more rarely sparsely pubescent in lower half within. Sepals 0.8-2 mm. long, 0.5-1.1 mm. wide. Petals 0.8-2.3 mm. long, 0.6-1.2 mm. wide. Filaments of the episepalous stamens 0.45-2.2 mm. long, those of the epipetalous ones 0.1-0.45 mm. long, the epipetalous stamens rarely lacking; anthers of the longer stamens 0.2-0.45 mm. long, those of the shorter ones 0.08-0.2 mm. long. Style 1.7-3 mm. long, glabrous or more rarely sparsely pubescent near the base; stigma 0.4-0.6 mm. thick, surrounded by the anthers at anthesis. Capsule (0.5-)0.8-l cm. long, 1-1.3 mm. thick along the wider axis, ascending. Seeds 0.7-1.3 mm. long, 0.3-0.35 mm. thick. Gametic chromosome numbers, n=14, 21. Autogamous, more rarely cleistogamous.
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Discussion
Camissonia andina grows sympatrically with its diploid relative, C. hilgardii, at a number of localities within the range of the latter. With the accumulation of additional chromosome number determinations from C. andina, it should become possible to develop a method for distinguishing tetraploids and hexaploids. Whether it will then become desirable to accord formal taxonomic recognition to tetratploid and hexaploid populations remains to be seen. In general, it now appears that hexaploids often have 40-90 percent 4-pored pollen grains, tetraploids mostly 10 percent or fewer (often none). Several of the collections examined (without chromosome number determinations) had 10-40 percent 4-pored pollen, and more chromosome counts will be necessary to draw a clear line between plants at the two different polyploid levels. At any rate, it is virtually certain that the type collections of this species is hexaploid (n=21), as an isotype (NY) had 27 of the 50 pollen grains examined 4-pored. The limited amount of evidence now available suggests that tetraploid races occupy the margins of the range of this species and are infrequent in the main portion of its range, where hexaploids appear to predominate. I have thus far been unable to discover any morphological distinctions between the two races other than the pollen difference just discussed.