Astragalus hoodianus Howell
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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
"... apparently somewhat local in Wasco County, Oregon, where it grows on hills from Hood River to a point a few miles east of the Dalles, and also on the opposite side of the river."—Holotypus, labeled "Open pine woods east of Hood River, Oregon, May 8,
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Synonyms
Astragalus conjunctus var. hoodianus (Howell) M.E.Jones, Phaca hoodiana (Howell) Piper, Cnemidophacos hoodianus (Howell) Rydb., Astragalus reventus var. hoodianus (Howell) M.Peck, Astragalus conjunctus var. oxytropidoides M.E.Jones, Tium oxytropidoides (M.E.Jones) Rydb., Astragalus reventus var. oxytropidoides (M.E.Jones) C.L.Hitchc., Cnemidophacos knowlesianus Rydb.
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Description
Species Description - Rather coarse, loosely tufted, with a thick, woody taproot and knotty, shortly forking caudex, pilosulous nearly throughout with fine, subappressed or loosely ascending hairs up to (0.5) 0.6-1 (1.1) mm. long, the herbage commonly gray- or silvery-silky, rarely greenish, the leaflets usually equally pubescent on both faces, sometimes glabrous above; stems several, erect or stiffly ascending from the decumbent base, stout, striate, 4-30 cm. long, composed of several congested lower internodes and ± 2-4 developed, often thicker ones (one of them up to 2.5-13 cm. long), inhibited beyond the first or second stout, elongate peduncle, the whole stem-axis nearly always less than half the full height of the plant; stipules submembranous, early becoming pallid or brownish, papery-scarious, ultimately fragile, (3) 5-11 mm. long, the lowest broad, obtuse, amplexicaul, at least in vernation connate through half or sometimes their whole length (the sheath sometimes ruptured in age), the upper ones lanceolate or deltoid-acuminate, semiamplexicaul, either all pubescent dorsally or the early ones glabrous; leaves (5) 7-20 cm. long, both cauline and gathered into radical tufts on short spurs, the latter with longer, slender petioles, the fully developed ones with 25-37 linear-elliptic or -oblong, oblanceolate, or sometimes ovate-oblong, obtuse, subacute, or rarely retuse, flat or loosely folded leaflets 5-27 mm. long, all commonly scattered along the rachis, disjointing readily when dry, the terminal one sometimes obscurely jointed; peduncles stiffly erect, stout, or the upper one quite slender and appearing terminal, 1.2-2.5 (3) dm. long, much surpassing the leaf; racemes at early anthesis rather dense, oval or oblong, (6) 10-30-flowered, soon elongating, narrow in fruit, the axis then (3) 5-18 cm. long; bracts membranous becoming scarious, lanceolate or linear-caudate, 2.5-9.5 mm. long; pedicels ascending, straight or nearly so, at anthesis 1-1.7 mm., in fruit clavately thickened, 2-3.7 mm. long; bracteoles nearly always 2, up to 2 (3) mm. long; calyx (10) 11-15 mm. long, villous-pilosulous or pilose with loosely ascending or spreading, black, fuscous, or white, sometimes variously intermingled hairs, the slightly oblique disc (0.8) 1-1.4 mm. deep, the membranous, pallid tube (5.7) 6-7.9 mm. long, 3.6-4.8 mm. in diameter, the narrowly lanceolate or lance-caudate teeth (2.6) 4.6-6.7 (7.5) mm. long, all approximate toward the dorsal side, commonly arched outward or hooked at apex, the ventral sinus very broad, the whole becoming scarious, fragile but marcescent; petals cream-colored, immaculate; banner recurved through ± 45°, rhombic-oblanceolate or -elliptic, rather deeply notched, 18-23 mm. long, 6-7.9 mm. wide; wings 16.2—19.2 mm. long, the claws 7.5—10.1 mm., the narrowly oblong-oblanceolate or lance-oblong blades 9.5-12.1 mm. long, 2.4-3.2 mm. wide, straight or a trifle incurved below the obtuse, erose, or obliquely triangular and subacute apex; keel 13.4—15.6 mm. long, the claws 7.3—9.8 mm., the obliquely triangular blades 6.2—7.7 mm. long, 2.9—3.6 mm. wide, abruptly incurved through 85-90° to the sharply deltoid apex; anthers 0.6-0.85 mm. long; pod erect, sessile, broadly oblong-ovoid to narrowly oblong-ellipsoid or lance-oblong, (1.1) 1.4-2.2 cm. long, (4.5) 5-7.2 mm. in diameter, straight or nearly so, truncate or broadly cuneate at base, rather abruptly contracted distally into a triangular or triangular- acuminate, rigidly cuspidate beak, decidedly obcompressed, low-carinate ventrally by the broad, prominent but obtuse suture, shallowly and openly groved dorsally, the lateral angles rounded, the green, fleshy valves becoming stiffly leathery or subligneous, brownish-stramineous, rugulose-reticulate, hirsutulous with rather stiff, ascending or rarely subappressed hairs up to (0.4) 0.5-1 mm. long, inflexed as a very narrow, sometimes subobsolete septum up to 0.7 (1) mm. wide; seeds olivaceous, sometimes with a black blotch at the hilum, or a black band across the middle, or soot-black throughout, smooth but dull, 2.3-3.1 mm. long.
Distribution and Ecology - Dry gravelly and grassy hillsides and canyon benches, mostly below 500 feet, occasionally a little higher, locally plentiful in and about the arid east end of the Columbia Gap, from near The Dalles downstream to Hood River, in Wasco and Hood River Counties, Oregon, and western Klickitat County, Washington.— Map No. 69.—Late March to June, the fruit long persisting.
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Discussion
The Hood River milk-vetch is closely related to A. conjunctus of which it might be loosely described as a robust, copiously pilosulous version. The longer and looser vesture provides an easily observed criterion at all stages of growth, but more valuable differential characters are found in the flowers. As compared with that of A. conjunctus the calyx of A. hoodianus is much more deeply cleft, so that the tube becomes campanulate and the (nearly always) much longer teeth are curved outward or distally hooked, not erect as in the commoner species The pods of these two vicariant astragali are alike in form, varying within nearly the same limits of length and diameter, but that of the Hood River milk-vetch is pubescent and decidedly fewer ovulate.
The pod of A. hoodianus, like that of A. conjunctus, varies from semibilocular to unilocular a circumstance which compelled Rydberg to enter the species under two genera in North American Flora. An inconsequential minor variant, whose calyx bears some black hairs in contrast to the more usual white ones, was also segregated as Cnemidophacos Knowlesianus; This does not deserve taxonomic status. The type-sets of A. hoodianus and the independently A. conjunctus var. oxytropidoides are in all probably part of one large collection distributed under different serial numbers. All are dated May 8, 1885 and Jones early recognized the two propositions as taxonomically synonymous (Jones, Contrib. West. Bot. 8. 9. 1898).
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Objects
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Distribution
Oregon United States of America North America| Washington United States of America North America|