Astragalus eucosmus

Variable in stature but commonly slender, thinly strigulose with fine, appressed or narrowly ascending hairs up to 0.2-0.6 mm. long, the stems and herbage usually green and the leaflets commonly glabrous above, rarely strigulose on both faces, the entire plant rarely subglabrous; stems erect or (especially northward) decumbent and incurved-ascending, (0.6) 1-4 dm. long, simple or almost so, leafless and purplish at base; stipules (1.5) 3-6 mm. long, dimorphic, the lowest ones approximate or loosely imbricated, broadly ovate, obtuse, early becoming papery and purplish-brown, amplexicaul and wider than the stem, the contrapetiolar margins either free and contiguous or shortly connate, the median and upper ones progressively narrower upward, the uppermost herbaceous, lanceolate or lance-acuminate, acute or subacute, free, often reflexed; leaves (2) 3-10 cm. long, the upper ones subsessile, with 9-15 (17) oblong, lance- or linear-oblong, oblong- obovate, or oblanceolate, obtuse or emarginate, often visibly penninerved, flat or loosely folded leaflets (4) 6-20 (30) mm. long; peduncles usually strictly erect and surpassing the leaf, but from diffuse stems incurved-ascending, (3.5) 5-18 cm. long; racemes (5) 7-25-flowered, compact at earliest anthesis, narrowly cylindrical but usually quickly elongating, becoming lax and secund, the flowers early declined, the axis mostly (2) 3.5—19 cm., rarely 1-2.5 cm. long; bracts submembranous, lanceolate, 1-3.5 mm. long; pedicels at anthesis 0.5-2 mm., in fruit recurved or dejected, 0.8-3 mm. long; bracteoles 0 (1); calyx 3.3-5.4 mm. long, strigulose or pilosulous with black, gray, or rarely white hairs, the disc 0.4-0.8 mm. deep, the campanulate, often purplish tube 2.5-3.5 mm. long, the subulate teeth 0.7-1.9 mm. long, the whole becoming papery, ruptured, marcescent; petals purplish, purple-tipped or -margined, pinkish-gray, or whitish, exceptionally white; banner gently recurved through ± 40°, oblanceolate to narrowly obovate-cuneate, openly notched, (4.1) 5.5-7.6 mm. long, (2.2) 2.8-3.7 mm. wide; wings (4.5) 5-6.3 mm. long, the claws (2) 2.3-3.1 mm., the narrowly oblanceolate or oblong- oblanceolate, obtuse, truncate, or emarginate, nearly straight blades (2.6) 3.2-4.1 mm. long, 1-1.5 mm. wide; keel 4-5.7 mm. long, the claws 2.1-2.9 mm., the half- obovate blades 2-3.2 mm. long, (1.1) 1.4-1.8 mm. wide, incurved through 90-100° to the rounded apex; anthers (0.15) 0.2-0.35 (0.4) mm. long; pod deflexed, sessile or almost so, the stipe (if present) vestigial and less than 0.4 mm. long, the body subsymmetrically or obliquely ovoid-ellipsoid, usually a little decurved (the ventral suture the more strongly convex in profile), (4) 5-13 mm. long, (2.3) 2.5-5.5 mm. in diameter, cuneate at both ends, shortly cuspidate at apex, when ripe a little turgid but obscurely triquetrous, the lateral faces convex, the usually narrower dorsal one flattened, the whole usually wider between the sutures than between the valves (thus compressed-triquetrous) but sometimes the reverse, the rather firmly papery valves densely strigose-pilosulous with black, gray, but commonly mixed black and white, more rarely mostly, exceptionally all white hairs up to 0.2-0.5 mm. long, inflexed as a hyaline septum (0.2) 0.4-1.2 mm. wide; ovules 4-8, commonly 6; seeds brown, smooth, 1.5-2.2 mm. long.— Collections: 122 (ii); representative: Viereck 1751 (COLO); Eastwood 469 (CAS, US, WS); Porsild & Breitung 10,825 (US); Cody & McCanse 3255 (CAS); Calder & Gillett 25,376, 25,421, 25,739, 26,376 (NY); J. M. Macoun 59,846 (NY); Macoun & Herriott 70,485 (NY); Marie-Victorin & al. 44-157 (CAS, TEX, WS); Fernald & al 28,591, 28,594 (GH, NY); Rouleau 497 (US); C. L. Hitchcock 16,767 (NY, RSA, WS); Suksdorf 302 (NY, WS); L. & R. Williams 3182 (NY, WS, WTU), 3331 (CAS, NY, WS); E. & L. Payson 2014 (CAS, NY); Ripley & Barneby 10,532 (CAS, RSA).

Stream banks and shingle bars, often about willow thickets or with shrubby cinequefoil, in aspen groves, open spruce or fir forest, sometimes in meadows moist in spring, at high latitudes on dry but cool, turfy banks and shores, without apparent rock preference, from sea level northward up to 10,500 feet in the Rocky Mountains, widespread in scattered stations from western Alaska to Baffin Island, south to Newfoundland and northern Maine, and along the east slope of the Rocky Mountains to the headwaters of the South Platte in Colorado; also extending feebly westward across the Continental Divide to the Selkirk Range in southern British Columbia, to the edge of the Snake River drainage in eastern Idaho (Fremont County), and to the headwaters of the Bear River in the Uinta Mountains, Utah.— Map No. 4.—Late May to August.

Astragalus eucosmus (becoming) B. L. Robins, in Rhodora 10: 33. 1908, based on A. oroboides var. americanus (American) Gray in Proc. Amer. Acad. 6: 204. 1864 (non A. americanus (Hook.) Jones, 1898), based in turn on Phaca elegans (neatly pretty) Hook., Fl. Bor.-Amer. 1: 144. 1831—"Prairies of the Rocky Mountains... Drummond"—Holotypus, K!—Astragalus elegans (Hook.) Sheld. in Minn. Bot. Stud. 1: 154. 1894, a later homonym of A. elegans Bge., 1869. Atelophragma elegans (Hook.) Rydb. in Bull. Torr. Club 32: 660. 1905.

Phaca parviflora (small-flowered) Nutt, ex T. & G., Fl. N. Amer. 1: 348. 1838 (non A. parviflorus Lamk., 1783).—"Vallies of the Rocky Mountains ... Nutt all."—Holotypus, labeled by Nuttall "Phaca *parviflora. R. Mts.," BM! isotypi, K, NY, PH!—Astragalus elegans var. curtiflorus (short-flowered) Rydb. in Mem. N. Y. Bot. Gard. 1 (Fl. Mont.): 242. 1900. A. curtiflorus Rydb. ex Jones, Contrib. West. Bot. 10: 64. 1902, an error, corrected by Jones on p. 87 of the same signature published the same day, hence illegitimate because not unequivocally accepted by the author.

Phaca oroboides fma. americana (American) Gand. in Bull. Soc. Bot. Fr. 48: xvii. 1902. —"Hab. Colorado et Wyoming simul, ad North Park, alt. 8500 ped. (G. Osterhout)."—Holotypus, labeled "North Park, on edge of Wyoming, July 25, 1898," Osterhout, LY! sheets numbered Osterhout 1065, RM, and dated July 24, 1898, WIS, are probably isotypi.

Astragalus eucosmus fma. albinus (albino) Fern, in Rhodora 28: 215. 1926.—"Newfoundland: .. .base of Ha-Ha Mountain, Ha-Ha Bay, July 17, 1925, Fernald, Wiegand, Gilbert & Hotchkiss, no. 28,588 ... "—Holotypus, GH!

Astragalus eucosmus var. facinorum (of exploits) Fern., l.e. 1926.—"Newfoundland: ... north bank of Exploits River below the falls, Grand Falls, July 3, 1911, Fernald, Wiegand, Bar tram & Darlington, no. 5795 ... "—Holotypus, GH! isotypus, NY!

Atelophragma atratum (blackened, of the dark pubescence) Rydb. in N. Amer. Fl. 24: 372. 1929.—"Type collected August 22, 1896, on Herchel Island, Yukon, Alvin Seale..."— Holotypus, DS!—Astragalus Sealei (Alvin Seale, 1871-1958, distinguished ichthyologist, creator and director of Steinhart Aquarium at CAS) Lepage in Le Nat. Canad. 85: 102, fig. z (phototypus). 1958, a legitimate substitute (non A. atratus Wats., 1871).

Astragalus eucosmus var. terrae-novae (of Newfoundland) Rouss. in Contrib. Lab. Bot. Univ. Montreal 24: 43. 1933.—"... nord-ouest de Terre-Neuve: Burnt Cape, July 17, 1925 (Fernald & al. 28594); Pistolet Bay, July 18, 1925 (Fernald & al. 25595); id., specimen en fleurs (25596: type, Gray Herbarium...); id., specimen en fruits, Aug. 11, 1925 (Fernald 25591: cotype, Gray Herbarium...)."—Cotypi, GH!

Astragalus eucosmus fma. villosus (softly hairy) Rouss. in op. cit. p. 44. 1933.—‘Terre- Neuve: Ha-Ha Mountains, July 17, 1925 (Fernald & al., 28,589); Ha-Ha Point, Aug. 5, 1925 (Fernald & al. 28590) ... "—Cotypi, GH!

Astragalus eucosmus fma. caespitosus (tufted) Rouss., l.e. 1933.—"Terre-Neuve: Bay of Island, Aug. 12, 1925 (Fernald & al., 28592)."—Holotypus, GH!

Astragalus eucosmus fma. leucocarpus (with white pods) Lepage in Amer. Midl. Nat. 46: 758. 1951.—"Alaska Range Distr.: Richardson Highway, Mile 150, Lepage 23155, June 14, 1948 ... "—Holotypus, LCU!

The elegant milk-vetch, A. eucosmus, is closely related to A. Robbinsii, differing chiefly in the sessile pod. The leaflets tend to be narrower and the flowers are often a little smaller, but neither of these features is diagnostic of A. eucosmus and fruits at least half formed are often necessary for identification. From the viewpoint of a narrow and inflexible logic it would be possible to append A. eucosmus to the collective species A. Robbinsii, regarding it as the culminating point in a series marked by ever shorter stipe and body of the pod; for as far as the fruit alone is concerned, the morphological gap between the elegant milk-vetch and A. Robbinsii var. Fernaldii or var. occidentalis is hardly greater than that between some other varieties of the A. Robbinsii complex. However the several races of A. Robbinsii occupy vicariant, mutually exclusive ranges of dispersal, only one of them at all far-flung, the remainder consisting of one or at best a few populations of an obviously relict character. The range of A. eucosmus is similar in general type and in many details to that of the whole collective species A. Robbinsii. In Labrador it is sympatric with A. Robbinsii var. Fernaldi; in the Rocky Mountains it is sometimes directly associated wth var. minor; and in Alaska it overlaps var. Harringtonii; yet in all these far distant places it maintains its integral individuality. Apparently A. eucosmus had already reached a terminal evolutionary stage before the last Pleistocene glaciations, while the largely sympatric A. Robbinsii has continued to undergoing modification since its continuous range was broken up by the ice.

Despite its great range A. eucosmus is only moderately variable, much less so than a glance at the long synonymy might suggest. Normally an erect plant of moderate stature, it is susceptible to dwarfing in open montane and far northern environments, where the stems become diffuse or weakly ascending as well as shorter, and the raceme tends to become shorter and more compact in fruit. The extensive series of specimens collected in Newfoundland by Fernald and associates beautifully illustrates a gradual passage from a tall plant with long, narrow racemes precisely matching the common Cordilleran type into a low ecotype with short, diffuse stems and more or less shortened racemes from wind-blown barrens by the sea. A diminutive specimen from Hudson Strait (Wakeham Bay, Polunin 1548, US) with stems only 6 cm. long and racemes reduced to about seven flowers exemplifies the extreme in this direction. Rousseau’s fma. caespitosus, var. terrae-novae (admittedly no more than a "forme ecologique") and fma. minor (excluding the basonymic Phaca elegans ß minor of Hooker) are minor variants of no taxonomic value. Both in eastern Canada and in the Rocky Mountains there is some variation in density and distribution of the pubescence, the leaflets varying from glabrous to sparsely pubescent (fma. villosus) above, and the lower surface from green to cinereous. An unusual plant with almost glabrous foliage and glabrous (or in the isotypus at NY nearly glabrous) calyx was distinguished as var. facinorum, but Fernald seems deliberately to have omitted mentioning that he collected in the type-locality only eight days later a perfectly normal example of A. eucosmus (Fernald & al. 5796). The hairs on the calyx and pod vary from black or fuscous to white, but are nearly always of mixed color. The proportion of light to dark hairs varies from plant to plant in a colony, sometimes even from pod to pod on a given plant, but the rare cases of concolorous pubescence, whether black or white, are only the termini of a continuous series of negligible variants.

The raceme of A. eucosmus ordinarily elongates rapidly during anthesis, the axis becoming about 3.5-19 cm. long in fruit with pods well spaced along its length. Instances of shortening have been mentioned already, but these are correlated with short, diffuse stems and an unfavorable habitat, mostly on exposed seashores at high latitudes in eastern Canada and Baffin. In central and northern Alaska, extending from McKinley Park west to Seward Peninsula and to the arctic slope of the Brooks Range (and just into Yukon), there occurs a remarkable, possibly distinct form in which a compact fruiting raceme is found on comparatively tall, erect stems, sometimes associated with broad leaflets of membranous texture and a sylvan or protected streamside habitat. In these plants, or many of them, it is not possible to attribute the shortening of the raceme to environmental factors; it is apparently inherited, and when (as often) the compact raceme is correlated with extremely small flowers and small pods only (4) 5-8 mm. long, the superficial appearance is striking. A specimen of this type from Arctic Yukon was described by Rydberg as Atelophragma atratum, and the proposition (amplified by a collection from the Alaska Range, Dutilly, Lepage & O’Neill 21,611, DAO) has recently been accepted by Lepage under the new name A. Sealei. Other representative examples are Scamman 5559 (GH); G. H. Ward 1362 (GH, US); Chambers 229 (GH, US); Mexia 2031 (MO, p.p.); Newsom (from Sable Pass) in 1930 (POM); and Galen Smith 2201 (ALA, UC), the last being the mesophytic extreme from the shade of willows along a brook at 2200 feet in the Alaska Range (which I prematurely annotated as an undescribed species). The general aspect of A. Sealei is that of a small-flowered version of A. norvegicus, the Eurasian analogue of A. eucosmus, and it may possibly represent a link between the Old and New World species. It is obviously very close to A. eucosmus, but there are difficulties in interpreting the relationship. In the first place perfectly typical A. eucosmus is sympatric in the Alaska Range with A. Sealei (cf. Cody & Webster 5541, US) and technically indistinguishable forms occur with A. Sealei on the arctic slope (cf. Spetzman 2120, US, and Scholander 395, US, the last with small pod, but racemes up to 8 cm. long). Then, although both the flower and the fruit of A. Sealei are on the average a little smaller than those of Cordilleran A. eucosmus, they are identical in form. Possibly A. Sealei represents an earlier stage in the evolutionary differentiation of a small-flowered American type from either the ancestral A. norvegicus or the precursor of both. It may have survived Pleistocene glaciation in an Alaskan refugium, whereas typical A. eucosmus may have immigrated into southeast Alaska since retreat of the last ice sheet. For the present it is scarcely possible to distinguish A. Sealei taxonomically, for all the possible known differential characters occur separately or even in pairs in populations of unquestionably typical A. eucosmus. The status of A. Sealei cannot be settled until the Alaskan plant has been compared with an adequate sample of A. norvegicus as this occurs in east Asia. It is possible that A. eucosmus is only a small-flowered Nearctic aspect of a circumpolar and temperate-alpine A. norvegicus.