250 ASCLEPIADACEAE 



1. Apocynum androsaemifolium L. Spreading Dogbane. (Man. 

 p. 738; I. F. f. 2Sgs-) In fields and thickets, Anticosti to B. C, Ga., 

 Neb. and Ariz. — Pennsylvania : Monroe ; Northampton ; Bucks ; 

 Delaware ; Chester ; Lancaster ; Franklin ; Bedford ; Dauphin ; 

 Huntingdon ; Allegheny. 



2. Apocynum cannabinum L. Indian Hemp. (Man. p. 738 ; I. F. 

 / 28p6.) In fields and thickets, Anticosti to B. C, Fla. and Lower Calif. 

 — Pennsylvania : Northampton ; Bucks ; Philadelphia ; Delaware ; 

 Chester ; Lancaster ; Franklin ; Bedford ; Dauphin ; Hunting- 

 don ; Allegheny. 



3. Apocynum album Greene. (Man. p. 739) On river shores, Me, 

 and Ont. to Mo. and Va. — Pennsylvania : Monroe ; Northampton ; 

 Bucks ; Lancaster ; York ; Allegheny. 



Family 6. ASCLEPIADACEAE Lindl. Milkweed Family. 

 Brect or decumbent herbs, not vines. 

 Hoods of the crown each with an )ncur\^ed horn within, i. Asclepias. 

 Hoods of the crown each with a crest-like keel, unappendaged. 



2. Acerates. 

 Twining vines. 



Pollen in a single waxy mass in each anther-sac. 

 Pollen-masses pendulous : anthers appendaged by a scarious membrane. 



3. Cynanchum. 

 Pollen-masses horizontal : anthers unappendaged. 4. Vincetoxicum. 



Pollen granulose, in 2 loosely aggregated masses in each anther-sac. 



5. Periploca. 

 1. ASCLEPIAS L. 

 Corolla orange : leaves, or some of them, alternate. 

 Leaves mainly alternate : stems erect or ascending. i. A. tuberosa. 

 Leaves, at least the upper ones, opposite : stems procumbent or reclining. 



2. A. decumbens. 

 Corolla red, purple green or white : leaves opposite or whorled. 

 Corolla red or deep purple. 

 Corona-hoods 4-6 mm. high : corolla 2-4 mm. broad. 



Corolla purplish red : hoods lanceolate. 3. A. rubra. 



Corolla deep purple : hoods oblong. 4. A. purpurascens. 



Corona-hoods 2-3 mm. high : corolla 4-6 mm. broad. 

 Plant glabrous or nearly so : leaf-blades lanceolate or oblong-lanceolate. 



5. A. incarnata. 

 Plant densely pubescent : leaf-blades nearly oblong. 



6. A. pulchra. 

 Corolla white, green, greenish purple or pink. 



A. Leaf-blades relatively broad, 

 a. Plants glabrous. 

 Leaf-blades cordate-clasping, undulate-crisped. 7. A. amplexicaulis. 

 Leaf-blades manifestly petioled or with petiole-like bases. 

 Leaves opposite : corolla white or greenish. 

 Umbel lax, the pedicels drooping : corolla greenish. 



8. A. exaltata. 

 Umbel dense, the pedicels radiating : corolla white. 



(^. A. variegata. 



