Astragalus flexuosus var. greenei (A.Gray) 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(1): 1-596.
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Family
Fabaceae
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Scientific Name
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Type
"Foothills of the Mogollon Mountains, New Mexico, April 20, 1880, E. L. Greene." Holotypus, GH! The type collection was distributed by Greene mixed with a second gathering, made in September of the same year in the Mimbres Mountains. This second element represents the summer-flowering A. Hallii var. fallax and has caused much confusion. The sheet in herb. Greene. (ND) labeled A"A. Greenei. Mimbres, Sept. 22, 1880" is largely var. fallax, but contains a fragment of the true species. One sheet at NY, labeled "Mogollon Mountains, April 10 (or 16), 1880," of which a Stanford University photograph has been distributed, is another mixture; the photographic enlargements show the flowering raceme of A. Greenei and the fruits of var. fallax. A duplicate (NY) bears additional data: "Duck Creek"; isotypus, dated April 17, 1880, K!
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Synonyms
Astragalus greenei A.Gray, Astragalus gracilentus var. greenei (A.Gray) M.E.Jones, Pisophaca greenei (A.Gray) Rydb., Phaca gracilenta A.Gray, Astragalus gracilentus (A.Gray) A.Gray, Tragacantha gracilenta (A.Gray) Kuntze, Pisophaca gracilenta (A.Gray) Rydb., Pisophaca stictocarpa Rydb., Astragalus stictocarpus (Rydb.) Tidestr.
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Description
Variety Description - Habit of var. flexuosus, the stems 1.5-4 dm. long, the herbage greenish- cinereous, the vesture appressed, incurved-ascending, rarely spreading-pilosulous; leaflets (9) 13-23, linear-oblong to obovate-cuneate; peduncles 1.5-13.5 cm. long; racemes (7) 10-30-flowered, the axis (1) 2.5-10 cm. long in fruit; calyx 3.5-6 mm. long, the tube 2.8-4.2 mm. long, 2.2-2.8 mm. in diameter, the teeth 0.7-2 mm. long; banner 9-10.8 mm. long; wings 8.6-9.6 mm. long, the claws 3.4-4 mm., the blades 5.6-6.8 mm. long, 1.9-2.9 mm. wide; keel 7-8.2 mm. long, the claws 3-4.1 mm., the blades 4-5.3 mm. long, 2-2.7 mm. wide; pod sessile or nearly so, the stipe not over 0.5 mm. long and hardly longer than wide, the body turgid or decidedly inflated, lance-ellipsoid to plumpy ellipsoid, oblong- or ovoid- ellipsoid, (12) 14—23 mm. long, (4) 5-9 mm. in diameter, straight or slightly in- or decurved, shallowly sulcate dorsally when narrow and both ventrally and dorsally when broad, when narrow the ventral suture prominent, the strigulose or villosulous valves not or sometimes brightly mottled; ovules 16-25.
Distribution and Ecology - Gullied badlands, dry knolls, bluffs and hilltops, with piñon and juniper, or sometimes in oak chaparral, 4400-7400 feet, locally plentiful in two somewhat disjunct areas: upper Rio Grande Valley in Santa Fe and Sandoval Counties, New Mexico; upper Salt and Gila Valleys in Gila County, Arizona, and western Grant County, New Mexico.—Map No. 14.—April to June.
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Discussion
The original descriptions of P. gracilenta and A. Greenei were drawn up from single specimens differing a good deal in size and inflation of the pod, and it is easy to understand how they have been maintained, either as species or varieties, by subsequent botanists. In northern Santa Fe County, where Fendler first met with it, P. gracilenta is locally abundant on sandy hills and sedimentary badlands, and the pod in this region is usually narrow and little swollen, mostly 4-5 mm., exceptionally up to 7 mm. in diameter, although it varies in outline and curvature. Along Rio Salado in Sandoval County, about fifty miles west of Santa Fe, a similar plant is found on bluffs and hillsides among junipers, and the pod here varies from about 4.5 to 6.5 mm. in diameter. A short distance westward, near the Rio Grande-San Juan watershed, the pod becomes decidely inflated and up to 7.5 mm. in diameter. These populations seem to represent one natural biological entity, A. gracilentus in the strict sense.
In the foothills of the Mogollon Mountains near the head of the Gila River, A. Greenei, which differs from P. gracilenta in no perceptible habital or floral character, presents a plumper, decidedly inflated pod 6-10 mm. in diameter, at first sight quite distinct in form. However in the Salt River drainage in Gila County, Arizona, otherwise identical plants exhibit great variation in the fruit, the most swollen examples being an exact match for A. Greenei, while the narrower forms agree precisely with some collections from the Rio Grande. It seems probable that the populations in the two main areas of dispersal are evolving in divergent directions and are already statistically different; but so long as they continue to produce a proportion of individuals which cannot be told apart, they cannot claim taxonomic recognition.
Over its whole range var. Greenei is very changeable in orientation of the pubescence, which often varies from one plant to the next in a colony. Plants with strigulose and with villosulous leaves, pods, or both, are found in close proximity near Santa Fe and also on the Natanes Plateau in Arizona. The typus of P. stictocarpa which came, like that of P. gracilenta, from Santa Fe, represents the form with subvillosulous fruits.
The descriptions of A. Greenei given by Jones (1923, p. 195, as A. gracilentus var.) and by Rydberg (1929, p. 327, as Pisophaca) are incorrect in important particulars. Both call for a pod about 1 cm. or more in diameter, and Jones has the flower 1.5-2 cm. long. These errors arose from the mixture of two species distributed by Greene under the label of A. Greenei, as already mentioned in the synonymy above. Jones specifically drew attention to the mixed nature of Greene’s material, but apparently transferred the epithet and concept to the element representing A. Hallii var. fallax.
It is possible that var. Greenei extends farther southward than suggested by the map. A flowering specimen from Zacatecas, (southwest of El Sauz, M. S. Johnston 2661A, RSA), certainly belonging in subsect. Scytocarpi and probably to the species A. flexuosus, is quite suggestive of var. Greenei. It cannot be identified exactly without the fruit.
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Objects
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Distribution
New Mexico United States of America North America| Arizona United States of America North America|