Astragalus crassicarpus Nutt. var. crassicarpus
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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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Synonyms
Geoprumnon crassicarpum (Nutt.) Rydb., Astragalus carnosus Pursh, Astragalus carnosus Nutt., Astragalus caryocarpus Ker Gawl., Tragacantha caryocarpa (Ker Gawl.) Kuntze, Phaca caryocarpa MacMill., Astragalus succulentus Richardson, , Geoprumnon succulentum (Richardson) Rydb.
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Description
Variety Description - Of medium stature, the stems decumbent with ascending tips, (0.8) 1—4 (5) dm. long; herbage bright or dark green, often cinereous or even silky in youth, the vesture composed of appressed or narrowly ascending, commonly lustrous hairs up to (0.4) 0.5-1.1 mm. long, the inflorescence pilose or pilosulous with largely or partly black hairs up to (0.45) 0.7-1.2 (1.4) mm. long; leaves 3.5-13 (18) cm. long, with (11) 15-29 (31) oblanceolate, elliptic, oblong-elliptic, narrowly obovate-cuneate, or (in some lower leaves) obovate to suborbicular leaflets 3—19 (22) mm. long, up to 2.5-6 (8) mm. wide; peduncles (1.5) 2-6 (10) long; racemes (5) 7-15 (23), exceptionally 20-35-flowered, the axis mostly 1-3.5 (7.5), exceptionally 4-14 cm. long; pedicels 2.7-4.5 mm. long in fruit; calyx (6.7) 7.7-11.3 (14) mm. long, the tube (5.2) 5.8-7.8 (8.6) mm. long, (2.5) 3.2-4.4 mm. in diameter, the teeth (1.3) 1.7—4.2 (5.8) mm. long; banner (16) 16.5-23.5 (25) mm. long, (7) 8-12.5 mm. wide; wings (13.8) 16-18.8 (20.2) mm. long, the claws 6.1-8.5 (9.5) mm., the blades (8.9) 10-12 (12.7) mm. long, (2.1) 2.6-4.1 mm. wide; keel (10.7) 12-14.5 (17) mm. long, the claws (5.6) 6-8.5 (9.1) mm., the blades (5.4) 5.8-7.5 (9) mm. long, (2.7) 3-4 mm. wide; anthers (0.55) 0.6-0.8 (0.9) mm. long; pod globose or plumply ovoid- or obovoid-oblong, 1.5-2.7 cm. long, 1.2-2.5 cm. in diameter; ovules mostly 52-68, averaging 60, rarely (in w. Texas) 38-44.
Distribution and Ecology - Prairies, rolling plains, old pastures, roadsides, and railroad rights of way, to the south sometimes on calcareous stony hillsides or about oak thickets, widespread and common from the Mississippi Valley west nearly to the foothills of the Rocky Mountains and north into southern Canada, southcentral Alberta to southern Manitoba, south to northeastern and trans-Pecos Texas, east to western (and 1 station on Lake Michigan in eastern) Wisconsin, eastcentral Iowa, western Missouri, and southwestern Arkansas, west to eastern Montana, northeastern Wyoming, eastern Colorado, and eastcentral New Mexico, up to 4450 feet in Colorado and 4500-5800 feet in western Texas, elsewhere mostly below 4000 feet—Map No. 101—Late March (southward) to July, the fruit ripe in summer and fall.
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Discussion
The common ground-plum, var. crassicarpus, is now most abundant in the southern part of its range. While it is still fairly frequent on the Great Plains, it is found chiefly along protected rights of way. Doubtless it was more generally distributed northward before the prairie was ploughed, for it is mentioned by nearly all the early travelers, who valued the green fruit as a summer vegetable. The variety is a remarkably adaptable astragalus, equally vigorous on chernozem and red-brown soils, in high-grass or low-grass prairie, on chalky sedimentary formations, alluvia of various composition, or loess. From Kansas southward the flowers are ordinarily bright purple, tending to become paler northward and westward; on the higher prairies the tips of the banner and wings are whitish and the color, as a whole, more fugitive from drying specimens. Albino forms (Cory 55,598, SMU) are occasional. The flowers vary considerably in size, but both the largest (Loring 3, OKLA) and the smallest (McCoy 580, OKLA) so far examined were collected in Oklahoma. The pubescence varies a good deal in length and density, the leaflets in length and width, and the pod in size and outline, but the variation is sporadic and falls into no significant geographic patterns.
Some remarkable forms of var. crassicarpus have evolved in far western Texas. One, distinguished by a strigulose ovary and pod, has been collected in the Glass Mountains in Brewster County (Warnock 4351, SRSC) and on Edwards Plateau in Irion County (Barneby 11,208). Another, known from several gatherings from Ord Mountain south of Alpine in Brewster County, combines a puberulent pod with exceptionally large flowers and long calyx-teeth. Even the glabrous fruiting states of var. crassicarpus in Brewster County, although to all appearances typical of the variety, are unusual because of the few (38-44) ovules. The ground-plums of trans-Pecos Texas seem to be in a state of active evolutionary fragmentation and deserve further study. At the western edge of the variety’s range in Quay County, New Mexico, and Kiowa County, Colorado, var. crassicarpus is represented at elevations of about 3800—4500 feet by populations of exceptionally robust plants with relatively long racemes of some 20-35 flowers, the axis becoming 4-14 cm. long in fruit. The raceme is suggestive of A. gypsodes, but the pod is characteristic of var. crassicarpus. This form also might repay further observations.
The common ground-plum is a member of the early spring flora, starting into activity with the spring thaw and bearing flowers within a few weeks. The fruits quickly assume their full size, but they require a period of two or three months, or probably longer, to reach full maturity. The majority of herbarium specimens are collected before the tissues of the exocarp have hardened; at this stage the pulpy walls collapse inward in drying, so that the pod appears coarsely and irregularly wrinkled on the sides and girdled lengthwise by a prominent ridge formed by the resistant sutures. In this condition the fruit fulfills Ker’s description of the pod of A. caryocarpus as being like a "stinted walnut." The sap in the mesocarp of the pods left to dry out naturally on the ground evaporates slowly, leaving intact an empty honeycomb of large, pale-walled cells, and the exocarp does not collapse inward. The truly ripe fruit thus presents an almost smooth exterior, the sutures remaining embedded in the valve walls or becoming, at best, only slightly prominent.
The first three names listed in the synonymy were based on material secured by Nuttall and Bradbury, either together or perhaps independently when traveling up the Platte River, the last partly on plants grown in England from seed supplied by Nuttall through the agency of the Fraser Nursery. Reference has already been made to the controversial status of the name A. crassicarpus. Whether the Fraser Catalogue will be ultimately accepted or not by the majority of botanists cannot be foreseen; however, Nuttall’s short, pregnant descriptive phrase, "Fruit about the size and form of A. physodes, but thick and succulent," is diagnostic of the common ground-plum when assessed in the light of Plates 58 and 58B of Pallas’s Species Astragalorum through which, unquestionably, A. physodes was known to Nuttall. Pursh’s A. carnosus, based largely on a Sophora, cannot be considered available until emended and typified by Nuttall in 1818; and the fact that Pursh cited A. crassicarpus of Frasers’ Catalogue as a probable synonym casts a further shadow of illegitimacy over his proposal. In default of A. crassicarpus, A. caryocarpus Ker, dating from 1816, must be the proper name for the ground-plum, and it was adopted as such by Fernald in Gray’s Manual (1950, p. 912).
The identity of A. succulentus as a form of A. crassicarpus or a close relative was early recognized by Hooker and has gone unquestioned since; it remains only to determine whether it belongs in the synonymy of var. crassicarpus or, as Rydberg assumed, in that of the Cordilleran var. Paysoni, equivalent of Rydberg’s Geoprumnon succulentum. Carlton House, the type locality, lies in the prairie belt of the Saskatchewan River well below 2000 feet altitude, offering an environment ideal for typical var. crassicarpus. Furthermore, freshly collected specimens from this region, communicated by Dr. Ledingham of Regina, have pale purple petals with whitish banner- and wing-tips and are identical with the form of var. crassicarpus found in the Dakotas and eastern Montana.
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Objects
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Distribution
Alberta Canada North America| Saskatchewan Canada North America| Manitoba Canada North America| Wisconsin United States of America North America| Minnesota United States of America North America| North Dakota United States of America North America| South Dakota United States of America North America| Montana United States of America North America| Wyoming United States of America North America| Nebraska United States of America North America| Iowa United States of America North America| Missouri United States of America North America| Kansas United States of America North America| Colorado United States of America North America| New Mexico United States of America North America| Oklahoma United States of America North America| Arkansas United States of America North America| Texas United States of America North America|