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APOCY>ACEAE, the Dogbane Family 



Herbs, with opposite simple entire leaves and regular flowers; 

 sepals, petals, and stamens each 5; petals united; stamens attached 

 to the corolla; ovaries 2, with a single style or stigma. 



la. Plant creeping or trailing; flowers blue, axillary, 2 3 cm. broad 



(spring) Periwinkle, Tinea minor. 



Ib. Plant erect or essentially so; flowers 1 cm. broad or less (4 12 



dm. high) 2. 



2a. Corolla pinkish, about 8 mm. long by 6 8 mm. broad (early 



summer) Dogbane, Apocynum androsaemifolium. 



2b. Corolla white or greenish, about 6 mm. long by 4 mm. broad 



(summer) 3. 

 3a. Leaves petioled, acute at the base 



Indian Hemp, Apocynum eannabinum. 

 3b. Leaves sessile, rounded or truncate at the base 



Indian Hemp, Apocynum eannabinum \ar. hypericifolium. 



ASCLEPIADACEAE, the Milkweed Family 



Herbs, with simple entire leaves and regular flowers; juice usually 

 milky; except in the first species, which is a twining vine. The flow- 

 ers have an unusual structure: calyx of 5 sepals; petals 5, united 

 with each other, and spreading or reflexed so that they conceal the 

 calyx; stamens 5, united with each other and with the stigma to form 

 a complex organ in the center of the flower; ovaries 2; on the back 

 of each stamen is a colored projecting hood, which is frequently the 

 most conspicuous part of the flower, and may be mistaken for the 

 corolla. 



la. Twining vine, with dark purple flowers (summer) 



Black Swallow-wort, Cynanchum nignim. 

 Ib. Stems not twining 2. 



2a. Leaves whorled (3 6 dm. high; summer) (Milkweed) 3. 

 2b. Leaves opposite or alternate 4.- 

 3a. Leaves in whorls of 4, lanceolate (flowers pink) 



Milkweed, Asclepias quadrifolia. 

 3b. Leaves in whorls of 4 7, linear (flowers greenish-white) 



Milkweed, Asclepias verticillata. 

 4a. Umbel sessile (4 8 dm. high; flowers green, summer) 



Green Milkweed, A cerates viridiflora. 

 4b. Umbel peduncled 5. 



5a. Leaves linear or narrowly linear-lanceolate (4 8 dm. high; 

 flowers greenish-white, summer) 



Green Milkweed, Acerates floridana. 

 5b. Leaves lanceolate or broader (flowers in summer) 6. 



6a. Leaves pubescent beneath 7. 

 . 6b. Leaves glabrous or nearly so 10. 



