ASCLEPIADACEiE 111 



2. A. cannabinum, L. Indian Hemp. 



Steins smooth, usually erect or ascending; leaves ovate to lanceolate, 

 usually appressed, sometimes slightly pubescent beneath, those on the main 

 stem petioled ; flowers white, in cymes, the central cyme the first to flower. 

 Very variable and represented by a large number of varieties. Moist open 

 places, Man.-Alta. 



LXIX. ASCLEPIADACE.ffi (Milkweed Family). 



Perennial herbs with milky juice, usually opposite leaves, and 

 regular flowers arranged mostly in umbels. Calyx free from the 

 ovary, 5-oleft; corolla 5-parted with a 5-lobed crown between the 

 corolla and the stamens, and attached to either one; stamens 6, 

 inserted on the base of the corolla, short and mostly monadelphous, 

 the pollen in waxy masses; fruit a 2-many-seeded follicle. 



1. ASCLfePIAS. Milkweed. 



The type species having the characteristics of the family, but the 

 crown attached to the stamen tube and made of 5 bodies covered 

 with concave or spreading hoods, each having within it a slender 

 horn; follicles large, on benl pedicels; seed with down attached. 



* FliOWEKS RED. 



» 



1. A. incarn^a, L. Swamp Milkweed. 



Smooth, erect, 1-4 ft. high, leafy; leaves oblong to lanceolate, usually 

 tapering to a point and often heart-shaped at the base; hoods scarcely as long 

 as the horn. Wet places, Man. and westward. 



** Flowers greenish white or tinged with purple. 



2. A. syriaca, L. Common Milkweed. 



Stout, tall, 2-4 ft. high, softJy pubescent; leaves oblong to oval, densely 

 pubescent beneath, soon smooth above; corolla whitish to purplish with a 

 tooth on each side of the horn. {A. Cornuti, Dene.) Rich soil, Man. and Sask. 



3. A. ovalifdlia, Dene. 



Low, 6-18 in. high, soft-pubescent; leaves ovate to lanceolate, short- 

 petioled, downy beneath; flowers greenish-white, sometimes tinged with 

 purple on the outside, the horn about the length of the lobes of the corolla. 

 Rich prairies, Man. and Sask. 



4. A. TerticillSta, L. * 



Stems slender, 1-2 ft. high; leaves linear, whorled; flowers greenish- 

 white, hoods about half the length of the horn. Around thickets, Man. and 

 Sask, 



