112 



ASCLEPIADACEAE 



Fig 

 Wats. 

 X 11/2 



Escondido, C. V. Meyer 224; San Diego, M. F. Spencer ; Witch Creek, Alderson. An extremely 

 broad-leaved form with ovate-lanceolate blades 4 to 5 inches long and 1 to 2 inches wide grows in 

 the high mountains of Fresno Co.: Cressman School, Pine Ridge, 4500 feet, Jepson 13,294; Eae 



Lake, 10,600 feet, Peirson 885. No geographic signifi- 

 cance attaches to this montane Fresno County form, since 

 d 1^^^^ *^1^? broad-leaved plants with blades % to 1 inch wide are 



. . ^ «^^^ /P^ sometimes found on the floors of the low valleys (Walnut 



\\\ ^ ^ \ // Creek; Sites, Colusa Co.). 



Refs. — AscLEPiAS MEXICANA Cav., Ic. 1:42, pi. 58 

 (1791), type from Mexico; Jepson, Fl. W. Mid. Cal. 382 

 (1901), ed. 2, 323 (1911), Man. 773, fig. 760 (1925). A. 

 fascicularis Dec.; DC, Prod. 8:569 (1844), type from 

 Cal., Douglas. A. macrophylla var. conwsa D. & H., Pac. 

 R. Rep. 5=:10, pi. 8 (1855), Pose Creek, Kern Co., Eeer- 

 mann. 



5. A. albicans Wats. Wax Milkweed. 

 (Pig'. 356.) Stem 3 to 10 feet high, the epider- 

 mi.s waxy white; herbage glabrate, the pedicels 

 pubescent; leaves in 3s, early deciduous, the 

 blades narrowly linear; peduncles V2 to 1 inch 

 long; umbels in a terminal panicle; pedicels 4 to 

 5 lines long; corolla greenish-brown; hoods yel- 

 lowish, saccate, truncatish, cleft along the top, 

 aboiit V2 a-s long as the anther-column; horns 

 slender, a little exserted; pedicels and follicles 

 erect, the latter slender, waxy, 4 inches long, 5 

 lines wide. 



Rockj- outcrops or in washes, 200 to 2500 

 feet: south- 

 eastern Mo- 

 have Desert; 

 Colorado Des- 

 ert. East to Arizona, south to Lower California. 

 Mar.-Apr. 



Field note. — A characteristic habitat note taken 

 from the field record is as follows: Our way leads west- 

 erly across the Colorado Desert and we are now approach- 

 ing the Jacumba Mts. An Asclepias (A. albicans) grows 

 in the rocks to the right of the wagon trail, its clusters of 

 tail stems (five to eight feet high) forming picturesque 

 objects on the summits of the boulder-pUed crags sixty to 

 one hundred feet above the bed of the wash of Myers 

 Creek. It also grows on the gentler rocky slopes where 

 it is equally prosperous, but not so striking in appear- 

 ance. This station is on the western margin of Imperial 

 County, near the Myers Creek bridge at the foot of the 

 Mountain Springs grade (Jepson Field Book, 45:85, 

 93. ms.). 



Locs. — Southeastern Mohave Desert : Sheep Hole 

 Mts. (Bull. S. Cal. Acad. 34 : 183) ; Whipple Mts., Peirson 

 11,503; Pinto Mts., Hall 6025. Colorado Desert: Santa 

 Rosa Mts. (8 mi. sw. of Coachella), Clary 178; Agua 

 Caliente near Vallecito, T. Brandccjee ; Myers Creek 

 bridge, foot of Mountain Springs grade, Jepson 11,780a. 

 Ref. — Asclepias albicans Wats., Proc. Am. Acad. 

 24:59 (1889), type loc. Los Angeles Bay, L. Cal., Palmer 

 588; Jepson, Man. 773 (1925). 



6. A. speciosa Torr. Ceeek Milkweed. 

 (Fig. 357.) Stem stout, 2 to 4% feet high, leafy to the top; herbage soft-tomentose, 

 or rarely glabrate in age; leaves in whorls of 2, the blades oval or ovate to oblong or 

 oblong-lanceolate, transversely veined, commonly acute, 4 to 7 inches long; petioles 



356. Asclepias albicans 

 a, fl.branchlet, X %; 6, fl., 

 c, hood, sho^^•ing the slender 

 exserted horn at summit, X 4 ; d, 

 long. sect, of hood, X 4; e, foUicle, 

 X V2. 



Fig. 357. Asclepias speciosa 

 Torr. a, flowering branehlet, X %; 

 6, fl., showing the ascending hoods and 

 reflexed corolla, X % ; c, hood and 

 horn, X2;d, follicle, X %. 



