Astragalus convallarius Greene var. convallarius
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Authors
Rupert C. Barneby
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Authority
Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(1): 1-596.
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Family
Fabaceae
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Scientific Name
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Type
"Sandy plains of the Colorado of the West, near the sources of the Platte. Nuttall."—Holotypus, labeled by Nuttall "Homalobus *campestris. Colorado of the Wt./R. Mts.," BM! isotypi, GH, K, PH!
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Synonyms
Astragalus campestris (Nutt.) A.Gray, Homalobus campestris Nutt., Tragacantha campestris (Nutt.) Kuntze, Astragalus serotinus var. campestris (Nutt.) M.E.Jones, Astragalus decumbens var. convallarius (Greene) M.E.Jones, Phaca convallaria (Greene) Piper, Astragalus convallarius var. typicus Barneby, Homalobus junceus Nutt. ex Torr. & A.Gray, Astragalus junceus A.Gray, Tragacantha juncea (Nutt.) Kuntze, Astragalus diversifolius var. junceus (Nutt.) M.E.Jones, , Astragalus junciformis A.Nelson, Homalobus junciformis (A.Nelson) Rydb., Astragalus junceus var. attenuatus M.E.Jones
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Description
Variety Description - Stems (1) 2-5 (7) dm. long; hairs of the herbage (0.35) 0.4-0.6 (0.7) mm. long, the leaflets sometimes glabrous above; leaflets, when present, 1-5 pairs, linear, Unear-filiform, or elliptic, commonly involute, exceptionally expanded and up to 3 mm. wide, 2—25 (33) mm. long; pedicels at anthesis 1—3.5 mm., in fruit 2.2-5 mm. long; bracteoles 0; calyx 4.2-6 mm. long, either black- or white-strigulose, the tube 3.4-4.8 mm. long, (2.2) 2.5-5.3 mm. in diameter, the teeth 0.5-1.4 mm. long; banner 8-11 mm. long; wings 8.5-10.5 mm. long; keel 8.1-9.4 mm. long, the blades 4.8-6.1 mm. long, 2.3-3 mm. wide; pod straight or nearly so; ovules 13-20; seeds 2.5-4.3 mm. long.
Distribution and Ecology - Hillsides, bluffs, benches and valley floors, in dry sandy, loamy, or clay soils of various origin and composition, without apparent rock preference, but most abundant on sedimentary formations, characteristically associated with sagebrush, 4150-7800 ("9000") feet, common and locally abundant in the Salt Lake, Uinta, and Green River Basins and around the edge of the upper Snake River Plains, southeastern Idaho, northern Utah, and southwestern Wyoming, extending south in Utah to the head of the Sevier River, east just into Moffat County, Colorado, and rarely across the Divide in Wyoming to the Wind, Sweetwater, and upper North Platte Rivers, west into northeastern Nevada; apparently isolated in the upper Missouri Valley near Helena, Montana.—Map No. 22.—May to August.
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Discussion
To the botanist who travels at all widely during early summer through northern Utah or adjoining parts of Wyoming or Idaho, the lesser rushy milk-vetch must quickly become a familiar or even commonplace member of the foothill flora; and its commonness and modest mien may deny it the appreciation due its many remarkable features. It is not hard, however, to imagine Nuttall’s delighted curiosity as he first came across this singular, apparently leafless vetch with its dingy little flowers strung out along filiform or very slenderly tapering axes which resemble the often naked leaf-stalks and thready ultimate branchlets and give rise to pods almost as slender as the stems themselves, laterally compressed and unilocular. At the time of their discovery Homalobus junceus and H. campestris, which represent no more than slender and robust phases of A. convallarius, were a completely novel type of astragaline plant, somewhat resembling in the reduced foliage the so-called Phaca picta (our A. ceramicus), but bearing a fruit like that of several other Homalobi first collected by Nuttall on the same journey.
Variation as now known in var. convallarius is rather considerable, especially marked in length of the pod, shape and length of the calyx-teeth, color of the hairs in the inflorescence, and development or suppression of leaflets in the lower leaves. Various combinations of these characters have served in the past as insecure foundations for maintaining three species (Rydberg, 1929, p. 257, in clave) and Jones’s var. attenuatus, but these artificially defined propositions do not correspond with biological realities, being more in nature of sporadic minor variants than self-perpetuating races. A more detailed analysis has been published elsewhere (Barneby, 1947, p. 28).
The cited combinations of Nuttall’s epithet campestris with Phaca and Astragalus are nomenclatural synonyms only, the substance of what was referred to under these names being in almost all cases some form of A. miser. The error arose originally with Gray (1864, l.c.) who misinterpreted Homalobus campestris Nutt. in the sense of our A. miser var. oblongifolius. The plant treated here as A. convallarius is Gray’s A. junceus (1864, p. 230) and includes that of Jones (1923, p. 75) together with his var. attenuatus.
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Objects
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Distribution
Wyoming United States of America North America| Utah United States of America North America| Idaho United States of America North America| Colorado United States of America North America| Nevada United States of America North America| Montana United States of America North America|