Astragalus anisus

Dwarf, loosely tufted, subacaulescent or shortly caulescent, with a woody taproot and (in older plants) a shortly forking caudex beset with flaccid, brown tatters of marcescent leaf-bases, densely silvery- or gray-pilose and strigose with appressed and narrowly ascending, almost straight or some sinuous and spreading, dolabriform hairs up to 0.8-1.6 mm. long, the leaflets equally pubescent on both sides; stems up to 5 cm. long, leafy, simple or shortly spurred at base, the internodes mostly concealed by stipules, a few sometimes developed and up to 1 cm. long; stipules 4—6 mm. long, pallid, submembranous, deltoid- or lance-acuminate, semiamplexicaul-decurrent, free; leaves 2-7 cm. long, petioled, with (7) 11-15 obovate, obovate-cuneate, or subrhombic, obtuse leaflets 4-10 mm. long; peduncles 1.5-3 cm. long, arcuate-recurved in fruit; racemes loosely but shortly 3-7-flowered, the flowers ascending, the axis little elongating, 0.5-2.5 cm. long in fruit; bracts lanceolate or ovate-acuminate, 2.5-4.5 mm. long; pedicels ascending, at anthesis 1.5-2.5 mm., in fruit a little thickened, 2-4 mm. long, persistent; bracteoles 0-2; calyx 11-13 mm. long, densely strigose-strigulose with white and sometimes a few shorter black hairs, the disc 1.3—2.1 mm. deep, the cylindric tube obliquely obconic-attenuate at base, 9-10.5 mm. long, 3.3-4.3 mm. in diameter, the subulate teeth 1.5-3 mm. long, the orifice oblique; petals pink-purple, little but regularly graduated; banner gently recurved through ± 40°, oblanceolate or spatulate, 18.8-21 mm. long, 8-12 mm. wide; wings 18.5-20.5 mm. long, the claws 10.5-13.5 mm., the oblong or lance-oblong, obtuse, straight blades 8.2-9 mm. long, 2.5-3.2 mm. wide; keel 16.5-18.5 mm. long, the claws 10.7-13.5 mm., the half-obovate blades 6—7 mm. long, 2.8—3.5 mm. wide, incurved through 70—80 to the blunt apex; anthers 0.6—0.85 mm. long; pod ascending or loosely spreading (humistrate), sessile, deciduous, obliquely globose, oblong-globose or broadly obovoid, (1) 1.3—1.8 cm. long, 8-13 mm. in diameter, turgid or moderately inflated, contracted at base into a short or obscure, obconic neck, minutely cuspidate at apex, straight or a trifle incurved, obcompressed and shallowly sulcate ventrally, flattened or rounded dorsally, the ventral suture either straight or shallowly concave in profile, the dorsal one convex throughout, often prominent and undulate, the fleshy valves becoming spongy and 0.3-0.4 mm. thick at maturity, then stramineous, irregularly rugulose but not (or vestigially) reticulate, finely strigulose with sinuous white hairs, inflexed as a complete septum 3-6 mm. wide; ovules 28-40; seeds soot-black, nearly smooth, dull, 2-2.4 mm. long.—Collections: 9 (v); representative: W. A. Weber 4706 (RSA); Jean Langenheim 1219 (CAS, NY, RSA); Ripley & Barneby 10,199, 10,207, 10,232 (RSA); Barneby 13,016 (CAS, NY, RSA).

Dry gravelly flats and hillsides, in sandy clay soils overlying granitic bedrock, usually among or sheltering under low sagebrush, 7500-7800 feet, known only from the valley of the Gunnison River for a distance of ± 40 miles upstream from the east portals of the Black Canyon, Gunnison County (the type-station near Pueblo almost certainly an error), Colorado.—Map No. 95.—May to July.

Astragalus anisus (unequal, presumably of the asymmetrically globose pod) Jones in Zoë 4: 34. 1893.—"Collected at Pueblo, Colo., by Miss A. P. Lansing, and communicated by Miss Alice Eastwood."—Holotypus, collected in 1892, POM! isotypi, CAS, UC!

In growth-habit, malpighian hair-attachment, and fine details of the flower the Gunnison milk-vetch, A. anisus, closely resembles several species of the preceding subsect. Missourienses. There can be little doubt that its affinities lie in this direction rather than among the Mollissimi to which it was referred by Jones (1923, p. 235) and afterward by Rydberg (1929, p. 446). The presence of a septum, which sufficed to exclude A. anisus from Xylophacos as defined by Rydberg, can no longer be considered of fundamental systematic import; indeed already admitted to the equivalent sect. Argophylli are several species with partially or fully bilocular fruits. However the plumply oblong or globose, dorsiventrally compressed, essentially beakless pod of A. anisus and its mode of dehiscence, by splitting through the septum and subsequently separating into a pair of carpel-like structures closed by the lidlike septum, have no counterpart in the section and entitle the species to a subsection of its own. The detached pod of the Gunnison milk-vetch is similar in form to that of A. crassicarpus var. cavus, which also dehisces in the same manner; and although the species would surely be misplaced among the Sarcocarpi, we may well have here a further clue to a common ancestry for the Argophylli and the pommes-de-prairie.

The published type-locality of A. anisus was almost certainly the result of some error in memory or in labeling. The city of Pueblo stands at the eastern foot of the last mesas of the Rocky Mountain piedmont, in high prairie country, and repeated search for the species in the neighborhood has been unsuccessful. The available habitats are quite out of keeping with the environment and elevation of the upper Gunnison Valley, where the species is locally abundant, clearly native, and probably endemic. In 1948, already suspecting a mistake in the original data, and unaware that A. anisus, lost to view for fifty years, would be rediscovered the following spring by that keen observer William A. Weber, I made enquiries of Alice Eastwood about the circumstances of the type-collection. Miss Eastwood’s characteristically vivid recollection was inconclusive so far as tracing the origin of the typus was concerned, yet her memories of the collector are worth permanent record: "Miss Alida Lansing was a protegee of mine when I taught in the Denver High School. She became interested in collecting beautiful specimens and pressing them to be made into cards or booklets for sale and she was financially successful. She married a lawyer and died about two years ago [ca. 1946]. She would not remember [where the astragalus was collected] even if she were alive and it is not at all unlikely that it might have been collected elsewhere. I named all her specimens ... Miss Lansing’s travels were quite extensive and I have no idea where she did her collecting."

Some "poor specimens" collected near Mancos, Colorado, early referred by Miss Eastwood (in Zoë 4: 16) to A. anisus, probably were lost in the 1906 fire. Jones surmised (Contrib. West. Bot. 13: 9) that they might represent A. lutosus, a narrow endemic of the Uinta Basin shales which could scarcely be expected so far south and could never be confused with A. anisus by so critical an observer as Alice Eastwood. Possibly the collection belonged to A. missouriensis var. amphibolus, of which Mancos is the type-locality and which greatly resembles A. anisus in habit of growth, dolabriform pubescence, and size and color of the flowers.