PEA FAMILY 343 



of the Sierra Nevada above the foothills, namely Astragalus bolanderi. In the foothills only one 

 species ordinarily occurs, the annual Astragalus gambelianus. On the arid slopes of the moun- 

 tains bounding the Great Basin or the deserts there are, however, a large number of species with 

 a marked proportion of endemics. The following extremely narrow endemics are found on the 

 east slope of the Sierra Nevada or on the desert slopes of the mountains of Southern California : 

 Astragalus webberi Gray in Plumas Co. ; A. austinae Gray on Castle Peak, Nevada Co. ; A. lem- 

 monii Gray iu Sierra Valley ; A. lentif ormis Gray in Eed Clover Valley, Plumas Co. ; A. inyoensis 

 Sheld. and A. atratus var. mensanus Jones on the Darwin Mesa, Inyo Co. ; A. panamintensis 

 Sheld. in the Panamint Range ; A. cimae Jones in the Providence Mts. region ; and A. albens 

 Greene in the region of Cushenbury Sprs., north side of the San Benardino Mts. These narrow 

 endemics are known from only one station or from two or three near-by stations and with many 

 other less restricted endemic species of the genus are all found outside the oval of the Great Valley. 



Historically the genus in western North America represents marked differentiation. The 

 tendency of the inflorescence to become capitate (as In A. rattanii, A. breweri or A. agrestis) is 

 an indication of high specialization. The reduction of leaflets in certain species of extremely 

 xerophytic aspect, such as A. serenoi, A. panamintensis and A. bicristatus, suggests a long period 

 of adaptation to the arid condition of the environment. The tendency of the pod to become in- 

 flated or two-celled is evidence of a more advanced condition than exists in the other large genera 

 of Legurainosae represented in California. The high number of specific units, the relative con- 

 stancy of characters common to each species, and the restricted distribution of many of these 

 species are all further indications of a highly specialized group. Altogether, Astragalus in west- 

 ern North America presents the view of a genus of ancient lineage which has long inhabited the 

 area Avhich it now occupies, and whose evolutionary tendencies have become relatively fixed by 

 isolation and adaptation. 



Note on the lethal qualities. — The herbage of Astragalus contains a poisonous principle 

 which affects the nervous system of horses, cattle and sheep and causes abnormality of movement 

 in the animal. Sometimes animals become uncontrollable and shy recklessly or run wildly. _ In 

 extreme cases death results. For California only certain species are listed as poisonous, chiefly 

 A. lentiginosus, A. hornii and A. mortonii, although others may be deleterious. Cf. Geo. Vasey, 

 Plants poisonous to cattle in Cal. (U. S. Dept. Agr. Rep. 1874:159-160,-1875) ; C. D. Marsh, 

 Loco Plants (U. S. Dept. Agr. Bull. 575:4-8,-1919) and The Loco Weed Disease (Parmer's 

 Bull. 1054:1-19, figs. 1-11, — 1919). Under the term Marihuana the herbage of a certain species, 

 probably A. leucopsis, is used by native Mexicans In Southern California as a narcotic drug. 



Bibliog.— Candolle, A. P. de, Astragalogia, 1-270, t. 1-50 (1802). Gray, A., A revision and 

 arrangement of the N. Am. species of Astragalus (Proc. Am. Acad. 6:188-234, — 1864) ; [Notes 

 on Astragalus species], (I.e. 6:524-527, — 1865) ; New Astragali (Proc. Am. Acad. 13:365-371, 

 — 1878). Greene, E. L., Some new species of the genus Astragalus (Bull. Cal. Acad. 1:155- 

 158,-1885) ; Three new Astragali (Lflts. 2:42-43,-1910). Jones, M. E., [Notes on Astragalus] 

 (Zoe 2:237-244,-1891; 3:286-298,-1893; 4:22-38, 267-277,-1893; 4:368-369,-1894; Proc. 

 Cal. Acad. ser. 2, 5:633-677,-1895; Contrib. W. Bot. 8:3-24,-1898; Zoe 5:42-47,-1900; 

 Contrib. W. Bot. 10:58-69,-1902; Contrib. "VV. Bot. 12:11-12,-1908); Revision of N. Am. 

 species of Astragalus, 1-288, pis. 1-78 (1923). Sheldon, E. P., On the nomenclature of some N. 

 Am. species of Astragalus (Minn. Bot. Stud. 1:19-24,-1894); Revised descriptions of the 

 Minnesota Astragali (I.e. 1:54-61, — 1894) ; A preliminary list of the N. Am. species of Astraga- 

 lus (I.e. 1:116-175, — 1894). Rydberg, P. A., Astragalus and its segregates as represented in 

 Colorado (Bull. Torr. Club 32:657-668,-1905) ; Notes on Fabaceae: I. Homalobus (Bull. Torr. 

 Club 50:177-187,-1923); II. Homalobus (I.e. 50:261-272,-1923); III. Homalobus, Kentro- 

 phyta (I.e. 51:13-23,-1924); IV. Xylophacos (I.e. 52:143-156,-1925); V. Xylophacos (I.e. 

 52:229-235,-1925) ; VI. Xylophacos (I.e. 52:365-372,-1925) ; VII. Geoprumnon, Hesperastra- 

 galus (I.e. 53:161-169,-1926) ; VIII. Hamosa (I.e. 54:13-23,-1927) ; IX. Hamosa (I.e. 54:321- 

 336,-1927) ; X. Atelophragma (I.e. 55:119-132,-1928) ; XI. Atelophragma (I.e. 55:155-164,— 

 1928); XII. Astragalus (I.e. 56:539-554,-1929); XIII. Tium (I.e. 57:397-407,-1930); 

 Astragalanae (N. Am. Fl. 24:251-462,-1929). 



A. Pods strongly inflated. 



I. Pods 1-celled (seed-bearing suture sometimes slightly intruded). 



1. Pods stipitate. 

 Stems low and tufted. 

 Perennials. 



Pods obovate, balloon-shaped, much rounded or obtuse at apex ; leaves commonly grayish- 

 puberulent ; leaflets narrow ; n. Sierra Nevada ; Yollo Bolly Mts. ; White Mts. 



1. A. Whitney i. 

 Pods broadly spindle-shaped; leaves essentially glabrous; leaflets broad; White Mts. 



2. A. oophorus. 

 Annual; pods broadly ovate, acute; Providence Mts 3. A. nutans. 



