ARISTOLOCHIACEAE, birthwort family 
ARISTOLOCHIA, birthwort 
Aristolochia serpentaria L., Virginia snakeroot, p. 573 
var. hastata Pate Duchartre 
var. serpenta 
A. tomentosa Sims, woolly pipe-vine, Dutchman’s pipe, p. 573 
ASARUM 
Asarum canadense L., wild ginger, p. 572 
ASCLEPIADACEAE, milkweed family 
ASCLEPIAS, milkweed 
Asclepias amplexicaulis Small, sand milkweed, bluntleaf milkweed, 
p. 1207 
A. hirtella emnel) Woodson, prairie milkweed, tall green 
eed (note that Farmer and Bell (1985) reduced 
atsgt taxon to subspecific status as A. longifolia Michaux 
ssp. hirtella (Pennell) Farmer & C. Bell, but this 
requires further study), p. 1208 
A. incarnata L., swamp milkweed, p. 1204 
ssp. incarnata 
f. albiflora Heller [G: A. incarnata] (the validity of this 
taxon has not been evaluated critically) 
f. incarnata 
A. meadii Torrey ex A. Gray, Mead’s milkweed, p. 1207 
A. perennis Walter, white milkweed, p. 1206 
A. purpurascens L., purple milkweed, p. 1204 
A. quadrifolia Jacq., whorled milkweed, fourleaf milkweed, p. 1206 
A. stenophylla A. Gray, narrow-leaved milkweed, p. 1208 
*+A. subverticillata (A. Gray) Vail, poison milkweed (Mihlenbach, 
1979 
A. sullivantii Engelm. ex A. Gray, smooth milkweed, prairie 
milkweed, p. 1206 
S: Steyermark G: Great Plains Flora M: Mohlenbrock 
