Monographs Details: Astragalus hidalgensis var. protensus Barneby
Authors:Rupert C. Barneby
Authority: Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
Family:Fabaceae
Description:Variety Description - Stems sparingly branched below, spurred at one or more nodes preceding the first peduncle, floriferous upward from near or above the middle; peduncles 6-9.5 cm. long, greatly surpassing the leaf; calyx 4-4.5 mm. long, its tube ± 2.6 mm., its teeth subulate, 1.3-1.8 mm. long; otherwise as given in the key. [Key] "Racemes elongate, distantly 10-17 flowered, the axis 5-12 cm. long in fruit; body of the pod longer and relatively narrower, (12) 14-23 mm. long, 4.3-5.5 mm. in diameter; ovules 14-18................25b. var. protensus"

Distribution and Ecology - Mountain ravines, probably in open woodland, ± 4500 feet, known only from Jacala, Hidalgo.—Map No. 8.—June to July, probably later.

Latin Diagnosis - a var. hidalgensi pedunculis racemisque elongatis et legumine longiori et angustiori 14-18- ovulato absimilis.

Discussion:It seems possible but hardly probable that the collection described above as var. protensus represents only an aberrant form of A. hidalgensis, for it differs so greatly in facies because of the loosening and lengthening of so many organs: stipules, peduncles, axis of the racemes, calyx-teeth, and finally the pod, which is narrowly oblong-ellipsoid rather than obliquely obovoid as in var. hidalgensis and contains seven to nine rather than only four or five pairs of ovules. The varieties of the Hidalgo milk-vetch are obviously too little known, and since they are nearly sympatric may prove to run together in nature. Field observation is required to settle their status.
Distribution:Hidalgo Mexico North America|