Monographs Details: Astragalus hintonii var. cofrensis Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
Description:Latin Diagnosis - a var. Hintoni stipulis, bracteis (herbaceis), calycisque dentibus brevioribus, petalis paullo longioribus magis exsertis, necnon ovario glabro absimilis.
Variety Description - Stems above ground up to 10 (15) cm. long; stipules 1.2-3.5 mm. long, all connate into a bidentate sheath, the upper ones not much longer than the lowest; peduncles 0.5-1.5 cm. long, all much shorter than the leaf; racemes 5-10-flowered; calyx 6.4-6.9 mm. long, the white-strigulose teeth 1.9-2.6 mm. long; keel 9.8-10.2 mm. long, the claws 5.4-5.8 mm., the blades 5.2-5.4 mm. long.
Distribution and Ecology - In open pine woods and in thin turf, about 10,200 feet, known only from the Cofre de Perote, Vera Cruz.—Map No. 8.—May to July, probably later.
Although much remains to be learned about the distribution and geographical variants of the Mexican Strigulosi, the pattern of narrow endemism presented by the material available at mid-century is probably real and no chance reflection of inadequate collecting. With this probability in mind, I have ventured to distinguish two varieties of A. Hintoni, even though each is known from only one or two gatherings and even though they differ in comparatively minor characters, the importance or constancy of which can hardly be foretold. The var. cofrensis is the more floriferous form, with (on the average) a few more flowers to the raceme, and its petals are a little longer absolutely (considerably so relative to the calyx, and appearing further exserted in consequence). The coincidence in var. cofrensis of short bracts, short stipules, and short calyx-teeth, which in Astragalus often vary in length together, is properly interpreted as a single difference. Since in A. tolucanus there are examples of glabrous and strigulous fruits from the same mountain, it is perhaps unwise to stress too heavily the glabrous ovary of var. cofrensis as a differential character.
The collectors describe var. cofrensis as having trailing stems up to 12 cm. in length and fragrant, mauve-purple flowers in heads which lie more or less prostrate. The stolon-like caudex-branches may reach a length of 3 dm. (and probably more) and give rise at intervals to adventitious roots.
Veracruz Mexico North America