376 



LEGUMINOSAE 



63. A. didymocarpus IT. & A. Twin Loco. {Fig. 215.) Stems slender, com- 

 monly dilTu-scly brancliotl from ba.se, 3 to 12 (or 24) inches hijjh; herbage strigulose, 

 the calyx hairs mostly blackish; loaves 1 to 3 inches long; leaflets 9 to 15, oblong to 

 linear, cuneate. deeply notched at apex, 2^2 to 5 lines long; spikes oblong-elliptic 

 to capitate, very densely flowered, 3l^ to 7 (or 12) lines long, the peduncles com- 

 monly exceeding the leaves; flowers remaining erect; corolla white and violet, IV2 

 to 2 lines long, scared}' exceeding the calyx; pods erect, short-ovate, deeply 2-lobed 

 lengthwise by the intrusion of the dorsal suture, incompletely 2-celled, corrugated 

 by strong transverse ridges, strigulose or setulose, 1 to IV2 lines long; seeds 2. 



Interior valleys and foothills, 50 to 3100 feet : South Coast Ranges (infrequent) 

 and San Joaquin Valley (mostly west side) south through the Mohave Desert to 

 the Colorado Desert and San Diego Co. Arizona 

 to Lower California. Mar.-Apr. 



Geog. note. — This slender annual is, next to Astra- 

 galus gambelianus Nutt., the most widely distributed of 

 any Californian species of this genus. Although it ex- 

 tends far eastward into the central Mohave Desert, we 

 have no records from the Sierra Nevada foothills north 

 of the San Joaquin River. A middle longitudinal band 

 in the corolla is sometimes whitish, the rest purplish and 

 veined. It is a uniform species, which is subject to little 

 variation. The var. dispermus differs only in color of 

 pubescence ; it is like the species in the form of its fruit 

 and especially in the details of the curved ridges on the 

 lobes. The septal intrusion in the variety varies slightly 

 in width but does not differ in this particular from the 

 species. The stations for the species as cited below 

 detail its range. 



Locs. — South Coast Eanges: Kirker Pass, n. of Mt. 

 Diablo, Brewer 1115; Livermore, Greene; Zapato Chino, 

 se. Fresno Co., T. Brandegee ; Palo Prieto Canon, e. San 

 Luis Obispo Co., Jepson 16,195. San Joaquin Valley: 

 Antioch, Davy 934; Byron, Bioletti; Tracy, C. F. Baker 

 2782; Huron, Eastwood; Bakersfield, Bavy 1706. Teha- 

 chapi Mts.: Caliente, Jepson 6753; Keene, Jepson 7162; 

 Rowen, Jepson 6717. Mohave Desert: Rosamond, Kern 

 Co., Bavy 2205; Leonis Valley, Bavy 2629; Ord Mt., 

 Jepson 5878. Coastal S. Cal.: Santa Cruz Isl., Jepson 

 12,091; Tujunga Canon, Peirson 2102; San Bernardino 

 Valley, Parish 6897; Vandeventer ranch, Santa Rosa 



Mts., Jepson 1415 ; Dripping Spr., Temecula Creek, Mum 5096 ; Dehesa, San Diego Co., T. 

 Brandegee; La Jolla, Jepson 11,874, Newlon 273 ; Paradise Valley, San Diego, Cleveland. 



Var. milesianus Jepson comb. n. Corolla purple, 3 to 4 lines long; racemes capitate, the 

 heads in fruit 7 lines long and as broad ; pods glabrous, rounded-ovoid, 2 lines long. — San Luis 

 Obispo Co.: Morro, Barber; San Luia Mt., Summers 203; San Luis Obispo, Jones. 



Var. dispenuus Jepson comb. n. Herbage grayish, strigulose; calyx conspicuously white- 

 villous; pods hairy. — Arid mesas and valleys, 100 to 2600 feet: Mohave and Colorado deserts. 

 East to Arizona, south to Lower California. 



Locs. — Mohave Desert: Arrastre Canon, n. side San Gabriel Mts., Peirson 398; Antelope 

 Valley, Bavidson; Mohave sta.. Mum 10,098; Barstow, Jepson 5429; Danby, Orcutt; Goffs, 

 K. Brandegee. Colorado Desert: Palm Sprs., Mt. San Jacinto, Geo. B. Grant; McCoy Wash, e. 

 Riverside Co., Hall 5940; Indian Canon, Collins Valley, ne. San Diego Co., Jepson 8851 (inter- 

 grade to the species) ; Blair Valley, e. San Diego Co., Jepson 8686; Carrizo Creek, T. Brandegee. 

 Cismontane Riverside Co. : CoahuUla Valley, Jepson 13,745. 



Var. obispoensis Jepson comb. n. Similar to the var. dispermus; pods glabrous. — San Luis 

 Obispo. 



Refs. — Astragalus didymocarpus H. & A. Bot. Beech. 334, t. 81 (1838), type from Cal., 

 Douglas; Jepson, Fl. W. Mid. Cal. 291 (1901), ed. 2, 235 (1911), Man. 576 (1925). Tragacantha 

 didymocarpa Ktze. Rev. Gen. PI. 2:944 (1891). Eesperastragalus didymocarpus Hel. Muhl. 2:87 

 (1905). A. catalinensis Nutt. Jour. Acad. Phila. ser. 2, 1:152 (1848), type loc. Santa Cataliaa 

 Isl., Gambel. Hesperastragalus catalinensis Rydb. Bull. Torr. Club 53:169 (1926). H. com- 

 paetus Hel. Muhl. 2:218 (1906), type loc. Friant (Pollasky), Fresno Co., Heller 8156. Var. 

 milesianus Jepson. Hesperastragalus milesianus Rydb. Bull. Torr. Club 53:169 (1926), type 



Fig. 215. Astragalus didymo- 

 carpus H. & A. a, habit, X % ; ft, 

 fl., X 4 ; c, pod, X 6 ; d, cross sect, of 

 pod, X 6. 



