Astragalus douglasii var. perstrictus (Rydb.) Munz & McBurney
-
Authors
Rupert C. Barneby
-
Authority
Barneby, Rupert C. 1964. Atlas of North American Astragalus. Mem. New York Bot. Gard. 13(2): 597-1188.
-
Family
Fabaceae
-
Scientific Name
Astragalus douglasii var. perstrictus (Rydb.) Munz & McBurney
-
Type
"Type collected in a hill valley between Campo and Jacumba [err. "Jocumba"], San Diego County, California, May 28, 1903, Abrams 3636..." Holotypus, NY! isotypi, DS, PH, POM, US!
-
Synonyms
Phaca perstricta Rydb., Astragalus parishii subsp. perstrictus (Rydb.) Abrams
-
Description
Deprecated: mb_convert_encoding(): Handling HTML entities via mbstring is deprecated; use htmlspecialchars, htmlentities, or mb_encode_numericentity/mb_decode_numericentity instead in /home/emu/nybgweb/www-dev/htdocs/science-dev/wp-content/themes/nybgscience/lib/VHMonographsDetails.php on line 179
Variety Description - Stems erect and stiffly ascending in clumps, 4-10 dm. long, floriferous in the distal third or subterminally; vesture rather sparse, the thick-textured herbage greenish, the leaflets strigulose on both sides; leaflets (11) 13—19, narrowly elliptic, lance-oblong, or narrowly obovate, obtuse or truncate-emarginate and mucronulate, 7—25 mm. long; peduncles erect, 7—13 cm. long, nearly equaling the leaf; racemes 12-20-flowered, the axis 4-10 cm. long in fruit; calyx as in var Parishii, 4.1—5 mm. long, white-strigulose, the broadly triangular or triangular-subulate, densely ciliate teeth 0.7—1.1 mm. long; banner 8.5—10 mm. long, 7—8.4 mm. wide; wings (0.8 mm. shorter to 0.6 mm. longer than the banner) 8.6—9.1 mm. long, the claws 2.7-3.6 mm., the blades 5.8-7 mm. long, 1.8-2.5 mm. wide; keel (as long to 0.7 mm. shorter than the wings) 8—9.1 mm. long, the claws 3—3.8 mm., the blades 5—6 mm. long, 2.4—3 mm. wide; pod (3.5) 4—6 cm. long, the valves strigulose, the funicular flange about 1 mm. wide; ovules (48) 58—67 (average about 60).
Distribution and Ecology - Stony hillsides and gravelly or sandy flats in open oak woodland, 3000—4000 feet, local but forming large colonies, known only from the mountains of interior southeastern San Diego County (Campo to Jacumba and Mountain Springs), California (and doubtless immediately adjoining Baja California). Map No. 113. —Late April to June.
-
Discussion
The Campo milk-vetch, var. perstrictus, first collected in 1875 by Edward Palmer, is an astragalus of great theoretical interest. The modified flower with its poorly graduated, strongly recurved petals and the shortly toothed calyx, pubescent in a characteristic pattern, are features common to A. Douglasii var. Parishii, var. perstrictus, and A. oocarpus (all native and the last two endemic to San Diego County) and denote a close relationship and common origin. The present variety combines with extraordinary precision the tall, erect growth-habit and thick-textured foliage of A. oocarpus with the somewhat fewer leaflets and, more importantly, the deciduous, thinly papery and obliquely ellipsoid, pluriovulate pod of A. Douglasii. The combination at once suggests that var. perstrictus arose as an amphidiploid, although we have no evidence that the parent species actually occur together at the present time. In any case var. perstrictus is a self-perpetuating entity which forms colonies of monomorphic individuals. Perhaps it may be more correctly interpreted as an independent mutation representing the first step in the evolutionary process that culminated in A. oocarpus, of which the emmenoloboid fruit must, in the context of the section, be considered a derived characteristic. A cytogenetic study may provide an insight into the origin of these interesting Californian Inflati.
-
Objects
-
Distribution
Baja California Mexico North America| California United States of America North America|