104 



ASCLEPIADACEAE 



Var. tomentosa Gray. Herbage densely tomeutose-pubescent ; calyx hirsute. — Plumas Co. to 

 Siskiyou Co. : Dutch Hill, Plumas Co., B. M. Austin; Butte Co., R. M. Austin; Viola, Tehama Co., 

 J. Grinnell; Sisson, K. Brandegee. 



Var. venusta Woodson. (Fig. 349.) Calyx and corolla soft-pubescent; corollas paler than 

 the average of the species. — Eastern San Gabriel Mts. (Mt. San Antonio, Peirson 147; Mt. Dis- 

 appointment, Ewan 7237) ; Santa Lucia Mts. (Santa 

 Lucia Peak, Jepson 4746). 



Eef s. — Cycladenia humilis Benth., PI. Hartw. 

 323 (1849), type loc. n. Sierra Nevada, Eartweg 

 309 : Jepson, Fl. W. Mid. Cal. 381 (1901), ed. 2, 322 

 (1911), Man. 769 (1925). Var. tomentosa Gray, 

 Svn. Fl. ed. 2, 2:400 (1886); Jepson, Man. 769 

 (1925). C. tomentosaGraj, Bot.Ca\.l:i7i (1876), 

 type loc. betw. Big Mdws. and Indian Valley, Plu- 

 mas Co., Lcmmon. Var. venusta Woodson; Munz, 

 Man. S. Cal. Bot. 379 (1935). C. venusta Eastw., 

 Bull. Torr. Club 29:77 (1902), type loc. Santa Lu- 

 cia Peak, Eastwood. 



ASCLEPIADACEAE. Milkweed Family 



Perennial herbs with milky juice. Leaves 

 opposite or whorled. Flowers regular. Ca- 

 lyx 5-parted. Corolla 5-lobed. Pistils 2, 

 with distinct superior ovaries ; styles distinct 

 below but united above into a short-cylin- 

 dric stylar disk. Stamens 5, inserted on the 

 base of the corolla and united into a tube 

 which is blended above with the stylar col- 

 umn, the united filaments (filament-column) 

 and united anthers (anther-column) being 

 here called the stamen-column and com- 

 monly bearing hoods (or appendages). An- 

 thers tipped with a scarious membrane 

 inflexed on the summit of the stylar disk; 

 between the anthers, on the sides of the sty- 

 lar organ, are cloven glands or elevated ridges slit longitudinally. Pollen grains 

 in each anther-cell united into waxy pear-shaped masses which are stalked and sus- 

 pended in pairs from the summit of the cloven glands, each pair of stalks deriving 

 its pollen-masses, not from the cells of one anther, but from contiguous anther-cells 

 of different anthers. Pollination entomophilous; the foot of the insect is caught 

 in the cloven gland or slit, and when drawn upward, drags out and bears away 

 the pollen-masses; in walldng over other flowers, the insect's foot is again drawn 

 through a slit, and the pollen-masses are left behind on the stigma, which is con- 

 cealed beneath the cloven structure. Fruit of 2 follicles. Seeds with a silky tuft 

 of hairs at the micropyle; embryo nearly as long as the seed, the cotyledons plane; 

 endosperm scanty. — (lenera 220, species about 1800, all continents, chiefly the 

 warmer regions of the earth. 



Bibliog. — Gray, A., Asclepias, etc. [of N. Am.] (Proc. Am. Acad. 12:65-73, — 1876) ; Gono- 

 lobus and Laehnostoma (I.e. 74-79, — 1876). Greene, E. L., On the classification of Asclepiads 

 (Pitt. 3:231-238,-1897). Vail, A. M., Studies in the Asclepiadaceae (Bull. Torr. Club 24:305- 

 310,-1897; 25:30-39, 171-182,-1898; 26:423-431,-1899; 28:485,-1901; 29:662-668,-1902; 

 30:178-179,-1903; 31:457-460,-1904). Frye, T. C, Morphological study of certain Asclepia- 

 daceae (Bot. Gaz. 34:389^13, pis. 13-15,-1902). Marsh, C. D., and Clawson, A. B., Asclepias 

 mexicana as a poisonous plant (U. S. Dept. Agr. Bull. 969, p. 1-16, pis. 1-2, — 1921) ; Woolly-pod 

 Milkweed, a dangerous stock-poisoning plant (U. S. Dept. Agr. Circ. 272:1-3, — 1923). Marsh, 

 C. D., The Milkweed Family in "Stock-poisoning plants of the range" (U. S. Dept. Agr. Bull. 

 1245: 25-27, pis. 32-35,-1924). Ball, W. S., & Bobbins, W. W., Mexican Whorled or Narrow- 

 leaf Milkweed (Mo. Bull. Cal. Dept. Agr. 24:219-220, col. pi.,— 1935). 



Fig. 349. CTCL.4DENIA HUMILIS Benth. 



var. VENUSTA Woodson, a, habit, X Vs ; 

 h, fl., X % ; c, long. sect, of fl., X%; d, 

 long. sect, of fl., X 2; e, seed, X %. 



