Astragalus mollissimus var. Earlei

Densely or loosely tufted, subacaulescent or shortly caulescent, the stems up to 1 (1.6) dm. long but mostly shorter, the herbage densely silky-pilose throughout, the longest, spreading or narrowly ascending, spirally twisted hairs up to 1.5-2.5 mm. long, the vesture becoming rufous in age; stipules mostly large and conspicuous, 5-15 mm. long; leaves 8-32 cm. long, with 19-35 oblanceolate, rhombic-ovate, or -obovate, obtuse or subacute leaflets (5) 10-30 (45) mm. long; peduncles (5) 8-17 cm. long; racemes oblong at anthesis, 15-36-flowered, the axis elongating, 4-15 cm. long in fruit; calyx (8.5) 8.8-10.5 mm. long, the tube (4.5) 5-7 mm. long, 0.8-3 (3.2) mm. in diameter, the teeth 2.4-4 mm. long; petals pink-purple or yellowish tipped and suffused or margined with dull purple, the wing-tips usually pale, whitish or yellowish; banner 12-17.5 mm. long, 4.5-7.5 mm. wide; wings 12-14.8 (15.7) mm. long, the claws 5.5-7.2 mm., the blades 7-8.6 (9.8) mm. long, 1.5-2.2 (2.5) mm. wide; keel 9-13 mm. long, the claws 7.6 mm., the blades 5.3—6.2 mm. long, 2—3 mm. wide; pod obliquely ovate- or lance-ellipsoid, 9-14 mm. long, 4—6.5 (9) mm. in diameter, more or less incurved, abruptly contracted distally into a short, unilocular beak, the valves thinly villous-tomentulose or loosely strigulose with almost straight, ascending, or curly and subappressed hairs less than 1 mm. long, occasionally nearly, rarely quite glabrous; ovules 20—30.—Collections: 90 (v); representative: Warnock 520 (MO, SMU, TEX); Mueller 8048 (NY, MO, TEX); Jones 26,433 (POM, US), 28,197 (CAS, POM); Eggleston 21,902 (MO, NY); Ripley & Barneby 11,129 (CAS, NY, RSA); Mexia 2552 (US), 2553 (CAS, NY); Johnston 8537 (GH); Stanford, Weatherford & Northcraft 253 (GH, NY).

Dry hills and grassy plains, equally vigorous on volcanic and calcareous soils, about 3750-5800 feet, widespread and common from the foothills of the Davis Mountains and the Big Bend country of trans-Pecos Texas south to southern Coahuila and west to the foothills of the Sierra Madre Oriental in central Chihuahua; intergradient populations combining either the larger flower of var. mollissimus with relatively broad, pubescent pod, or narrower flower of var. Earlei with glabrous pod represent the species northward into the Texas Panhandle and southeastern New Mexico.—Map No. 97.—March to June, exceptionally and sporadically in fall.

Astragalus mollissimus var. Earlei (Greene ex Rydb.) Tidest. in Proc. Biol. Soc. Wash. 48: 40. 1935; and in op. cit. 50: 21. 1937, based on A. Earlei (Franklin Sumner Earle, 1856—1929, mycologist and plant collector) Greene ex Rydb. in N. Amer. Fl. 24: 444. 1929.— "Type collected in Limpia Canyon, Texas, April 5—May 3, 1902, Earle & Tracy 226 Holotypus, collected April 25, 1902, NY! isotypi, G, GH, MO, ND, TEX, US!—Note that Earle & Tracy 331, collected April 2, 1902, labeled "A. Tracyi Greene, type-collection," ND, NY, MO, TEX, are conspecific but not type-material. Limpia Canyon is in the Davis Mountains, Jeff Davis County.

Astragalus pervelutinus (very velvety) Rydb. in N. Amer. Fl. 24 : 444. 1929.—"Type collected near the City of Chihuahua, April 1, 1885, Pringle 189..."—Holotypus, NY! isotypi PH, US!

Earle’s woolly locoweed is very closely related to var. mollissimus, differing ideally, and over a great part of its range consistently, in the narrower calyx, ordinarily shorter flower, and (with reservations) pubescent pod. However, on the Staked Plains of northern Texas, the common representatives of A. mollissimus combine the small, narrow calyx of var. Earlei with a pod glabrous or nearly so as in var. mollissimus, while the latter, as defined by its large flower, shows an increasing tendency for a pubescent pod as it comes southward through eastern New Mexico to the Texas line. In the Chisos Mountains of the Big Bend, the pod of otherwise characteristic var. Earlei varies from densely pubescent throughout to glabrous except for a few hairs about the beak; and there are a few records from this area of a truly glabrous ovary and pod (cf. Moore & Steyermark 3227, MO). The varieties thus intergrade in all differential characters. For the purposes of identification of the intermediate forms, I have chosen arbitrarily to regard the proportions of the flower, more constant in a given colony than the vesture of the fruit, as the deciding factor.

The typus of A. pervelutinus does not seem to differ substantially from other collections from near Chihuahua City, several of which, including an isotypus (US), were identified as A. Earlei by Rydberg. The vesture of these Mexican plants is perhaps (especially when young) a trifle more silken than is usual in the Texan material of Earle’s woolly locoweed, but the flowers and pods are identical. In southern Coahuila and San Luis Potosi some populations combine with the narrow calyx, or with the narrow firm pod of var. Earlei, the ordinarily ampler flower of var. irolanus, and here again one has difficulty in separating the varieties.