Astragalus gruinus Barneby
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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(2): 597-1188.
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Family
Fabaceae
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Scientific Name
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Type
Baja California: Vallecitos, Sierra San Pedro Martír, 8200 ft., 21 September, 1930, Wiggins & Demaree 4969. Holotypus, NY! isotypi, DS, K!
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Description
Latin Diagnosis - ab Inftatis affinibus et similibus omnibus legumine receptaculo haud articulato cum pedicello demum deciduo, ab A. douglassii var. Parishii petalis purpureis, ovulisque multo minus numerosis, ab A. Palmeri legumine majori pluriovulato, ab A. allochroo (procul allopatrico) ovulis ±12- nec 5-10-paribus ulterius absimilis.
Species Description - Astragalus gruinus Relatively coarse, diffuse, perennial, with the growth-habit of A. allochrous, strigulose with appressed or in small part ascending, mostly straight hairs up to 0.4-0.6 mm. long, the stems glabrescent toward the purplish base, more densely pubescent distally, the herbage green or greenish-cinereous, the leaflets either glabrous or thinly hairy above; stems decumbent and incurved-ascending, 3-4 dm. long, simple, or branched or spurred at up to 6 nodes preceding the first peduncle, floriferous upward from near or below the middle; stipules submembranous becoming papery, 2-5 mm. long, the lowest often broader than the long, decurrent-amplexicaul around ± ¾ to nearly the whole stem’s circumference, the upper ± semiamplexicaul, with triangular or triangular-acuminate, deflexed blades; leaves 6-12 cm. long, the lowest shortly petioled, the rest subsessile, with (9) 17-25 narrowly to broadly oblong-elliptic or lance-oblong, obtuse, truncate- emarginate, or subacute, flat or loosely folded leaflets 5-17 long; peduncles rather stout, incurved-ascending, 5-9 cm. long, a little shorter than the leaf; racemes at first rather densely and shortly (10) 12-18-flowered, the flowers at first ascending, then spreading in age, the axis somewhat elongating, 2-5 cm. long, produced as an appendage beyond the last flower; bracts membranous, pallid, triangular-lanceolate, 1.5-2.5 mm. long; pedicels at anthesis ascending, 0.5-1.5 (2) mm. long, in fruit arched outward or divaricate, somewhat thickened but readily disjointing together with the marcescent calyx and pod; bracteoles usually 2, at or below the base of the calyx, rarely 0; calyx 5.3-6.9 mm. long, densely strigulose with black and a few white, sometimes all white hairs, the subsymmetric disc about 1 mm. deep, the tube 3-4 mm. long, 2.2-3.2 mm. in diameter, the narrowly subulate teeth 2.3-3 mm. long, the tube ruptured in age; petals purple, drying brownish-stramineous; banner abruptly recurved through ± 80°, broadly rhombic-ovate beyond the cuneate claw, openly notched, 8.6-11 mm. long, 5.6-7 mm. wide; wings as long or nearly so, 8.5-10.6 mm. long, the claws 3.3-3.8 mm., the narrowly oblong-elliptic, obtuse, lunately incurved blades 5.7—7.2 mm. long, 2—2.5 mm. wide; keel 7—8.6 mm. long, the claws 3.3—3.8 mm., the half- obovate blades 4—5.3 mm. long, 2—2.7 mm. wide, abruptly incurved through ± 90° to the triangular, ultimately obtuse, often slightly porrect apex; anthers 0.5—0.65 mm. long; pod spreading, sessile on and firmly attached to the scarcely elevated receptacle, obliquely ovoid-ellipsoid or subglobose, bladdery-inflated, 1.8—2.8 cm. long, 1-1.5 (or when pressed seemingly up to 1.9) cm. in diameter, broadly rounded at base, contracted distally into a suberect, broadly deltoid, laterally compressed beak 2—5 mm. long, the body subterete, shallowly sulcate ventrally, the thin, pale green or purplish-tinged, strigulose valves becoming papery, stramineous, sublustrous, finely cross-reticulate, not inflexed, the funicular flange 1.2—1.5 mm. wide; dehiscence apical, after falling; ovules 24—26; seeds brown, pitted, dull, 2.6-2.9 mm. long.
Distribution and Ecology - In pine forest, 5000-9500 feet, known only from the crest and both slopes of Sierra San Pedro Martir, Baja California (distr. Norte). Map No. 115. June to October.
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Discussion
The crane milk-vetch, A. gruinus, is at first sight a rather commonplace astragalus to anyone familiar with the coarser and commoner Oocarpi, such as A. Douglasii or A. allochrous, both of which it resembles in habit. It differs from the nearly sympatric A. Douglasii var. Parishii in its purple petals, shorter calyx-teeth, and much fewer (24-26, not 42-62) ovules, and from A. allochrous, safely distant in Arizona and eastward, in slightly more numerous leaflets, more compact racemes, and more numerous ovules, even though the average pod is appreciably smaller. Other related Oocarpi with purple flowers are A. Palmeri, the Baja California representatives of which have smaller, fewer-ovulate pods combined with fewer leaflets, and a range of dispersal mostly at lower elevations along the desert-bordering mountains; and A. idrietorum of the deserts south of San Pedro Martir, similar to A. Palmeri but with even fewer ovules and pod-walls of thinner texture. The strongest differential character of A. gruinus is the disjointing pedicel, which falls together with the ripe fruit and marcescent calyx, a feature unique among the normally piptoloboid Inflati of North America. The South American Inflati are apparently similar in this feature to A. gruinus, but none of them resemble our species at all closely in fine detail.
The commoner form of A. gruinus from the neighborhood of Vallecitos and La Grulla has greenish foliage, a black-hairy calyx, and leaflets glabrous above, but the species is variable in density and color of the pubescence. An approximate topotypus, historically the first collection (Goldman 1224, in 1905, NY), has cinereous leaves, white-strigulose calyces, and leaflets thinly hairy above.
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Objects
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Distribution
Baja California Mexico North America|