Astragalus aboriginum

Title

Astragalus aboriginum

Authors

Rupert C. Barneby

Scientific Name

Astragalus aboriginum Richardson

Description

8. Astragalus aboriginum

Perennial, with a stout woody taproot and (in mature plants) a congested or ± knotty, pluricipital caudex, very variable in stature and pubescence, the stems and herbage varying from green and almost glabrous to densely silky-strigose, villous, or villous-tomentulose, the hairs straight and appressed, or straight and spreading, or incumbent, or curly, the longest up to 0.2-0.8 mm. long, the leaflets either equally pubescent on both sides or medially glabrescent to quite glabrous above; stems several or numerous, 0.2-2.6 dm. long, erect and ascending in clumps, or decumbent with incurved-ascending tips, or diffuse and trailing, simple or nearly so; stipules (1) 2-7 (10) mm. long, the large, approximate or loosely imbricated lower ones ovate, obovate, rhombic-obovate, or suborbicular, purplish becoming papery and brownish, several-nerved, amplexicaul and usually wider than the stem, the contrapetiolar margins in contact but either free or shortly connate (rarely united for over ½ their length), the median and upper ones narrower, subherbaceous, lanceolate or narrowly oblong, obtuse or acute, semiamplexicaul and usually about ½ as wide as the stem; leaves 1—7 (10) cm. long, all sessile or rarely all petioled, with 7-15 lance-, oblong-, or linear-elliptic, sometimes lance- oblong or almost truly linear, acute or obtuse, flat or marginally involute leaflets 3-27 (35) mm. long, 1—7 mm. wide; peduncles erect or incurved-ascending (sometimes eventually humistrate from diffuse stems), 2-12 cm. long, as long or longer than the leaf; racemes (2) 6—30-flowered, compact at early anthesis but nearly always quickly loosening, the axis (1) 2-11 cm. long in fruit, the pods commonly secund; bracts membranous or membranous-margined, narrowly lanceolate or sublinear, 1.2-5 mm. long; pedicels at anthesis ascending, 0.8-2.2 mm. long, in fruit arched outward, recurved, or deflexed, (1.2) 1.5-3.5 mm. long; bracteoles 0; calyx (3.7) 4.2-6.4 (9) mm. long, loosely strigulose to densely villous-pilosulous with black, fuscous, and usually some or many (all) white hairs, the subsymmetric disc 0.4-1.1 (1.6) mm. deep, the tube (2.1) 2.7-3.9 (5) mm. long, (1.8) 2-3 (3.5) mm. in diameter, the subulate teeth 1-3 (4) mm. long, the whole becoming papery, marcescent unruptured; petals whitish (or when first expanded flesh-pink) or cream-colored, the banner commonly veined and sometimes distally suffused with lavender or brownish-purple, the keel-tip (usually prominently) maculate; banner recurved through 40-50°, broadly oblanceolate, elliptic-oblanceolate, or obovate-cuneate, openly notched, 7.5-12.6 (14.5) mm. long, 4-7.4 (8) mm. wide; wings 7—11.8 (12.4) mm. long, the claws 3-5 mm., the narrowly oblong or oblanceolate, nearly straight blades 5-8.1 (9.3) mm. long, 1.7-2.7 (3.4) mm. wide just below the lobed apex; keel (6.1) 6.7-9.6 mm. long, the claws 3-4.6 (4.9) mm., the half-obovate blades (3) 4-5.1 (5.6) mm. long, (1.7) 2-2.8 (3.2) mm. wide, incurved through 75-100° to the rounded apex; anthers (0.3) 0.35-0.55 (0.6) mm. long; pod pendulous (or if humistrate falling at random angles), stipitate, the slender stipe 2.5-8 mm. long, the body obliquely, rarely subsymmetrically narrow-elliptic (linear-oblong) in profile, nearly always slightly decurved, the ventral suture convex and the dorsal one straight or a trifle concave, 1-2.6 (3.1) cm. long, 3-6 (7) mm., or in Alaska sometimes 6-9 mm. in diameter, usually tapering (or when broad more abruptly contracted) into the stipe, cuneate or cuneately tapering and short-acuminate at apex, laterally compressed, bicarinate by the prominent but filiform sutures, the faces at first nearly flat becoming ± distended and low-convex, sometimes a little tumid when fully mature, the thin, greenish but commonly red- or purple-tinged or -dotted (but not mottled), glabrous or less often strigulose valves becoming stramineous, translucent, finely reticulate, inflexed as a very narrow, sometimes obscure (rarely obsolete) septum 0.1-0.6 mm. wide; ovules 8-16; seeds brown, ocher-brown, or greenish, sometimes purple-speckled, smooth but dull, 2-2.9 mm. long.—Collections: 151 (vii); representative material cited in the discussion. Stony shores, river bluffs, rock slides, exposed crests, and stony or turfy mountain slopes and meadows, in the Rocky Mountains coming out into the parks and openly wooded foothills and on the northern prairies to river bluffs and badlands, in dry or moderately moist (but not waterlogged or permanently moist) soils, apparently most abundant on calcareous bedrock but found also on granites, schists, and other formations, near sea level at its north- and eastward limits, up to 11,000 feet in the western mountains, locally plentiful in the Rocky Mountains from northeastern British Columbia to southern Colorado, west to the Wallowa Mountains in northeastern Oregon, the East Humboldt Mountains in northeastern Nevada, and the Wasatch in central Utah, eastward interruptedly to the Black Hills of South Dakota, western North Dakota, and across southern Canada to Manitoba and (very interruptedly) southern Quebec (Lake Timiskaming and Gaspé Peninsula); also locally abundant in the upper Yukon Valley, Yukon; and in the tundra zone and barren grounds of Alaska and District of Mackenzie from near Point Hope east to southeastern Victoria Island (ca. long. 104° W.), south in Alaska to the Alaska Range, in Yukon to the Ogilvie Mountains, and in Mackenzie to Great Bear Lake and the Mackenzie Valley; eastern Siberia.—Map No. 6. Late May to August. Astragalus aboriginum, (of the Cree and Stone Indians, who gathered the root as a spring vegetable) Richards, in Frankl. Jour., Append. 746. 1823 ("aboriginorum"). Sandy plains in the neighbourhood of Carlton," i.e., on the North Saskatchewan River above Prince Albert.—Presumed holotypus, labeled "N. America, 1819-22, Richardson," BM! isotypus, labeled "Carlton House, Richardson 285," K (but ovary glabrous)! A spm. labeled "N.-W. America, Franklin Exped., Dr. H[ooker]," GH, ex herb. Boston Soc. Nat. Hist, is perhaps another isotypus.—Phaca aboriginum (Richards.) Hook., Fl. Bor.-Amer. 1: 143, tab. LVI. 1831 ("Aboriginorum"). Tragacantha aboriginum (Richards.) O. Kze., Rev. Gen. 942. 1891. Homalobus aboriginum (Richards.) Rydb. in Mem. N. Y. Bot. Gard. 1 (Fl. Mont.): 246. 1990 ("aboriginorum"), Atelophragma aboriginum (Richards.) Rydb. in Bull. Torr. Club 32: 660. 1905. Phaca glabriuscula (rather glabrous) Hook., Fl. Bor.-Amer. 1: 144. 1831.-"Vallies of the Rocky Mountains, Drummond."-Holotypus, K!-Astragalus glabriusculus (Hook.) Gray in in Proc. Philad. Acad 1863, p. 60. 1863, by implication, & in Proc. Amer. Acad. 6. 204. 1864. Tragacantha glabriuscula (Hook.) O. Kze., Rve. Gen. 945. 1891. Astragalus aboriginum var. glabriusculus (Hool.) Rydb. in Contrib. U. S. Nat. Herb. 3 (Fl. Black Hills): 492. 1896. Homalobus glabriusculus (Hook.) Rudb. in Mem. N. Y. Bot. Gard. 1 (Fl. Mont.): 246. 1900. Atelophragma glabriusculum (Hook.) Rydb. in Bull. Torr. Club 32: 660. 1905 ("glabriuscula"). Astragalus glabriusculus var. major (larger) Gray in Proc. Philad. Acad. 1863, p 60. 1863 -"116. in the mountains, at middle elevations.’’-Holotypus, colected by Hall & Harbour in the Colorado Rocky Mountains, in lat. 39-41°, in 1862, GH! isotypi, K, NY! A. glabriusculus var spatiosus (spacious) Sheld. in Minn. Bot. Stud 1: 156. 1894, a superfluous substitute. A spatiosus (Sheld.) A. Hell., Cat. N. Amer. Pl., Ed. 2. 7. 1900. Astragalus Forwoodii (William Henry Forwood, 1838-1914, sometime Surgeon-General, U.S. Army, naturalist with Gen. Sheridan’s expedition, 1879-82) Wats. in Proc. Amer. Acad. 25: 129. 1889.—"Black Hills of S. Dakotah... Dr. W. H. Forwood, U. S. A., May, 1887."-Holotypus, GH! Astragalus Richardsonii (Sir John Richardson, 1787-1865, surgeon-naturalist with the Franklin Expedition) Sheld. in Minn. Bot. Stud. 1: 126. 1894, a new name for A. vagimatus (sheathing, of the stipules) sensu Richards, ex Hook., Fl. Bor.-Amer. 1. 149. 1831 (non Pallas, 1800, tab. 36).—"Woody country between lat. 54° and 64°, Dr. Richardson." —No holotypus certainly identified as such; spm. authent., labeled simply A. vaginatus BM. the spm. at GH labeled "284. Astragalus vaginatus. Richardson's Arctic Plants (ex herb. Lowell.) is probably a duplicate of the preceding. -r An- sn iqn_ Atelophragma lineare (linear, of the leaflets) Rydb. in Bull. Torr. Club 40. 50, 191 . "Yukon Territory: Foot of Lake Lebarge, 1899, J. B. Tarleton 34b... —Holotypus, collected June 23, 1899, NY! isotypus, US!—Astragalus linearis (Rydb.) A. E. Porsild in Rhodora 41: 250. 1939. Astragalus aboriginum var. fastigiorum (of summits) Jones, Rev. Astrag. 135. 1923.- "The type is my material from Mt. ["Mr."] Haggin, Montana."—Holotypus, collected by Jones on Mt. Haggin near Anaconda at 8500 ft., July 20, 1905, POM (2 sheets)! isotypi, GH, NY! Atelophragma wallowense (of the Wallowa Mountains) Rydb. in Bull. Torr. Club 55: 122. 1928. "The type was collected on the Wallowa Mountains, Oregon, July 28, 1899, Cusick 2267... ’’—Holotypus, GH! isotypus, P!—Astragalus Forwoodii var. wallowensis (Rydb.) Peck, Man. PI. Ore. 447. 1940, & in Madrono 6: 135. 1941. Atelophragma Herriotii (William Herriot, 1870-1930) Rydb. in Bull. Torr. Club 55: 123. "Manitoba: Qu’Appelle River, Macoun & Herriot 70479 ... "—Holotypus, collected at mouth of Qu’Appelle River, June 28, 1906 (Herb. Geol. Surv. Canad. No. 70,479), NY! isotypus, CAS! Astragalus scrupulicola (dwelling on “sharp and angular pencil-like talus") Fern. & Weath. in Rhodora 33: 238, fig. 1. 1931.—“Gaspe County, Quebec: ... Calcareous slaty talus, southern slope of Mt. St. Pierre, July 5, 1931 (flowers and young fruit), Fernald, Weatherby & Stebbins, No. 2455 (TYPE in Gray Herb.) ... ’’—Holotypus, GH! Astragalus aboriginum var. Muriei (Olaus Johan Murie, b. 1889, zoologist with Bur. of Biol. Surv., collected extensively in Alaska and Yukon in 1920-36) Hult., Fl. Alaska & Yukon 1080. 1947.—“Central Yukon R. distr.: Porcupine R., 45 miles from the mouth, Murie 2162 ...’’—Holotypus (herb. Hult.), not examined. Astragalus Lepagei (Rev. Ernest Lepage, 1905- ) Hult., Fl. Alaska & Yukon 1761, fig. 4. 1950.—“Arctic Coast distr.: Umiat, July 29, 1948, Lepage 23601 (type ...).”—Holotypus (herb. Hult.), not examined. Because of variations in stature, vesture, and amplitude of the foliage, the Indian milk-vetch, A. aboriginum, cannot be characterized in a few succinct words. Leading features are the large, veiny, obtuse stipules at base of the stems and the toothed wing-petals which distinguish members of sect. Hemiphragmium from habitally similar and sympatric Oroboidei. The nodding flowers vary somewhat in size but hardly at all in shape or relative proportions of the parts; they are usually conspicuously bicolored on account of the blot on the keel-tip, which often becomes more intensely colored when dry. There is a wide range of variation in length and orientation of the stems, much of it clearly correlated with accidents of habitat and exposure. The pod is almost uniformly half-elliptic in profile with nearly straight dorsal and convexly arched ventral suture, so that it appears to be arched a little downward. Its stipe varies from about as long to over twice as long as the tube of the calyx, and the body varies in width from 3.5 to 6 mm., or in the far Northwest up to 9 mm. in diameter. Nevertheless the flowers and fruits of the Indian milk-vetch are everywhere so much alike in fine detail that it seems certain we are dealing with only one specific type, however variable its component parts may be in other features.

The Indian milk-vetch (with its close relative A. Cottoni) is isolated in our flora, but has several close kindred in Eurasia, notably A. australis (L.) Lamk. Polunin (Circumpolar Arctic Flora 287. 1959) has treated the latter and at least the boreal manifestations of A. aboriginum as forming an aggregate species, and there is much to be said in favor of this view. The problem of specific limits in sect. Hemiphragmium involves, however, a whole complex of forms widely dispersed from the Pyrenees and Carpathians across northern Asia into Mongolia and Siberia and a number of proposed segregates such as A. Tugarinovii Basilevsk., A. Kaufmannii Kryl., and A. pseudoaustralis F. & M., known to me only from descriptions or totally inadequate specimens. There is no alternative but to postpone study of this and attendant nomen-clatural questions and limit the field of inquiry to what must be called A. aboriginum in America. A discussion of our plants may be divided profitably into two parts, one dealing with the Indian milk-vetches of the Rocky Mountains and southern Canada generally, one with the Arctic and Alaskan types.

Astragalus aboriginum in the United States and Canada south of lat. 60° N.

With few exceptions the synonyms already cited are based on plants from this area, and they have arisen through independent observations of the perplexing diversity in type and distribution of the vesture and in width of the leaflets varying from linear-elliptic or almost exactly linear to broadly or subrhombically elliptic. The pubescence of the leaves, stems, and inflorescences, often black or fuscous distally, fluctuates from sparse or almost lacking to quite dense, and the herbage from bright green to cinereous or even silvery-canescent; moreover, whether closely or sparsely set, the hairs vary from straight and appressed to straight and spreading or incumbent and curly. Whatever sort of hair predominates, the leaflets (of whatever shape) may be either glabrous or strigulose on the upper face, and the pod varies independently of other factors from glabrous to strigulose. Combinations of these variable characters have served from early times to distinguish varietal and specific segregates of A. aboriginum, although these have all been recognized as close to the prototypical Indian milk-vetch. It so happened that as soon as one combination of variables was accepted as taxonomically significant, logic compelled an equally respectful consideration of its peers. Granted that shape of leaflets, presence or absence of hairs on the upper leaf-surface and the pod, and appressed or spreading vesture are racially correlated, we are presented with the theoretical possibility of sixteen combinations. For purposes of analysis and comment, we might visualize these combinations by means of the following diagrammatic key:

In the area under discussion, all theoretically possible combinations with the exception of that designated as cc have been found at least once, and it would be rash to assume that the one still missing does not exist. The forms are far from equally common. The most widely dispersed types of A. aboriginum are those with relatively broad leaflets; they extend over the whole species-range and also represent the species in all the known outlying or marginal stations. Among the presumably primitive broad-leaved forms, the majority by far have loosely pubescent foliage (and the majority of these leaves pubescent on both sides) together with a glabrous pod. But in the Rocky Mountains plants differing only in their shorter, appressed, and often sparser vesture (with leaflets more often glabrous above) are encountered within the same range and in the same environments. A less common combination is that of broad leaflets and a pubescent pod, although these features are known to occur either with appressed or with spreading vesture. The group of forms with linear or linear-elliptic leaflets is of comparatively northern and northwestern range, extending from Manitoba to North Dakota, Alberta, and very rarely to Montana and the Black Hills, and recurs also in Alaska. In this group strigulose and villosulous foliage are of about equal frequency, but a glabrous pod, as always, is much the commoner. Although it is generally possible to assign a given plant to one of the lettered forms defined in the key, there are transitional individuals; and in many colonies there is variation from plant to plant, especially in pubescence characters. The following mixtures, which could probably be added to by means of mass-collections, have been found in sets of duplicate herbarium specimens, several of them on single sheets (the type-collections of A. Forwoodii, A. glabriusculus var. major, A. aboriginum var. fastigiorum, and Atelophragma wallowense among them): a + b; a + d; a + b + d\ a + c; b + d; bb + d\ c + d; d + dd\ d +e; d -f h; e + /; e + g\ e + ee\ f + h; h + //; and b + d + dd. Obviously many populations of A. aboriginum, whether broad- or narrow-leaved, are highly unstable as to type, distribution, and density of the pubescence, although examples of glabrous and pubescent pods in the same colony are few. Shape of the leaflets, which might be thought superficial in theory, is more nearly fixed within the average population, although in a review of all the material available it is a simple matter to trace an intergradient series from the broadest elliptic to the narrowest linear type. In the circumstances there can be no advantage in maintaining any of the segregates proposed in ignorance of the complexities involved.

Astragalus aboriginum in Alaska, Yukon, and Mackenzie The arctic and subarctic races of A. aboriginum introduce three new features, petioled stem leaves, larger flowers, and broader pods than found in the Rocky Mountains. Southward from the 60th parallel, the leaves of the Indian milk-vetch are all sessile or nearly so, and the flowers are always small, with banner 7.5-12.5 mm. long. Northward from upper Yukon Valley, the leaves are often slender-petioled, and the flowers are occasionally much larger, with banner up to 14.5 mm. long. As in the more southern area, the pod is much more often glabrous than strigulose, but it is more variable in size, sometimes reaching a width of 6-9 (as opposed to an average 3.5-6) mm., and furthermore it is sometimes less strongly compressed and incipiently bladdery. Several pubescence types occur in the Northwest, but none seem to be correlated with shape of leaflets or with size of the flower-parts or fruits. In the upper Yukon Valley, the leaflets are prevailingly linear or nearly so, but the leaves vary from sessile to petiolate. Above the Arctic Circle, the leaflets are usually of a broad type, and the leaves are most often petioled, but neither of these characters is more than dominant in any region which might reasonably be expected to harbor a distinct or endemic race. Three types, fully intergradient but at the extreme point of development easily recognized, can be made out in the material from Alaska, Yukon, and Mackenzie District. The first, locally abundant in the upper Yukon Valley, closely mimics the linear-leaved forms found in the foothills of the Alberta Rocky Mountains (variants e, f, and g); it has developed stems (±5-7 visible internodes), mostly sessile leaves, small flowers, and a strongly compressed, flat-sided pod. In the same area (but whether ecologically separated or not is unclear) there occurs a form with petioled leaves and sometimes more turgid pod. The latter corresponds with Atelophragma lineare and leads into what might be called the Behringian variant, which is typically developed the length of the Brooks Range in Alaska, extending south to the Alaska Range, east to the Ogilvie Mountains in central Yukon, and west an unknown distance (possibly as far as the Yenisei River) into Siberia. The Behringian variant is a broad-leaved type, usually of slender, decumbent growth and lowly stature (±3-4 visible internodes), and is characterized further by strongly connate lower stipules, petioled leaves, and small flowers. The pod is variable in size but seems to average a little broader (at least in relation to its width) than that of the Cordilleran forms of A. aboriginum and is sometimes perceptibly swollen with convex faces. The third boreal American type resembles the last in its low stature but is coarser in all its parts, has gray-pubescent (usually gray-villosulous) foliage and, on the average, substantially larger flowers. It is typically developed north of the tree line from the east end of the Brooks Range east to Victoria Island and south over the tundra to Great Bear Lake, it might be called the Mackenzie variant. It has been identified with  A. Richardsonii Sheld., but this is probably a mistake, for the original A. vaginatus of Richardson, according to Hooker’s description and the specimens at BM and GH, is apparently equivalent to form d as defined above in the schematic key. The type-locality of A. Richardsonii, in "woody country between 54° and 64° N," also suggests one of the more southern Canadian rather than one of the tundra phases of the Indian milk-vetch. There remain other isolated gatherings which fit into none of these categories exactly. The form described as A. Lepagei is one of these, a relatively tall, glabrescent plant with large flowers and broad pods; but copious typotypes from Umiat (Lindsay 2359, Wiggins 12,883, K. L. Chambers 197) show much variation in length of the (mostly very narrow) leaflets and in width (5-9 mm.) of the strongly flattened pod. The typus of var. Muriei, described as having leaflets glabrous above but a pubescent pod, has not been examined and has not been equated with any particular variant.

The Behringian variant of A. aboriginum scarcely differs from some European and Asiatic material of A. australis. It was apparently included by Gontscharov (1946, p. 66) in his concept of an arctic-alpine A. australis widely dispersed across northern Eurasia, and its villosulous phase seems (e descr.) identical with or extremely close to A. Tugarinovii N. Basilevsk. (in Not. Syst. Herb. Hort. Petrop. 5: 69. 1924.—"in prov. Enniseisk. Goltschicha.") which Gontscharov has reduced to synonymy. On the other hand the plant of the Brooks Range passes, by scarcely perceptible steps, through the intergradient Atelophragma lineare into the ordinarily taller plant known traditionally in America as A. aboriginum. The taxonomy and nomenclature of the whole complex remain to be worked out in detail, but this can be achieved only on a circumpolar basis. The following summary of the American variants is offered as a stepping stone in the direction of the biosystematic revision which is required before many problems in sect. Hemiphragmium can be solved.

Summary of the American Variants of A. aboriginum

a. Leaflets elliptic, pubescent above and beneath, the vesture villosulous. Pod glabrous.—Rocky Mountains from Alberta to centr. Colorado, w. through centr. Idaho to the Wallowa Mountains, Oregon, the E. Humboldt Mountains, Nevada, and centr. Utah; Black Hills, South Dakota (= var. fastigiorum, p.p.; Atelophragma wallowense, p.p.).—Representative: Hitchcock & Muhlick 11,169 (CAS, NY, WS, WTU), 10,883 (NY, SMU, WS, WTU, some mixed with d), 12,909 (RSA, WS, mixed with c and b); Jones 51 (POM, NY); Ripley & Barneby 8224 (CAS, GH, RSA, UTC, mixed with b), 10,390 (RSA). One spm. from s. Yukon (Porsild & Breitung 10,689, NY) technically referable here intergrades with e.

aa. Leaflets and pubescence as a, but pod pubescent.—Uncommon, Rocky Mountains from ±56° N. in British Columbia s. to n.-w. Wyoming; s.-centr. Saskatchewan; Gaspe Peninsula, Quebec ( = A. aboriginum sens. str., e descr.; A. scrupulicola).—Representative: Raup & Abbe 3576 (NY); F. J. Hermann 13,314 (RSA); Breitung 15,704 (NY); Fernald & Weatherby in Pl. Gray. Exsicc. 559.—The robust form greatly isolated in Quebec and described as A. scrupulicola is closely matched by Dr. Hermann’s cited collection from Alberta. The supposed differences in the auricles of the wing-petals between a single flower from Gaspe and the illustration of A. aboriginum hardly deserved the emphasis accorded by Fernald.

b. Leaflets elliptic, pubescent above and beneath, the vesture appressed. Pod glabrous. Often with a, but less widely dispersed and less common, s. Alberta and s. British Columbia to n.-w. Wyoming.—Representative: Hitchcock & Muhlick 11,973 (NY, RSA, WS), 12,909 (NY, RSA, WS, some mixed with a).

bb. Leaflets and pubescence as b, but pod pubescent.—Foothills of the s. Alberta Rocky Mountains, apparently rare.—Representative: Brinkman 3545 (NY); Moodie 48 (NY, mixed with d).

c. Leaflets elliptic, villosulous beneath, glabrous above. Pod glabrous—Montana to Colorado, w. to the Wallowa Mountains, Oregon, e. to the Black Hills, South Dakota; Fort Saskatchewan, Alberta (= A. Forwoodii, p.p.; Atelophragma wallowense, but note that a and d also occur in the Wallowa Mountains).—Representative: Hitchcock & Muhlick 10,883 (CAS); Parry 2 in 1864 (CAS, NY); Ripley & Barneby 8933 (RSA).

cc. Leaflets and pubescence as c, but pod pubescent. Unknown.