ASCLEPIADACEAE 



509 



Common throughout the range, except in the pine-barrens, there 

 rare or wanting; nearly always as a weed. 



5. A. sibiricum Ait. (A. album Greene; A. hypericifolium Ait.). In 



dry soil or along streams: Ont. to B. Col., L. I., and N. Mex. 

 Rare and local over most of our range, but not in the pine- 

 barrens. 



6. A. pubescens R. Br. In moist soil; sometimes in fields: 



Ont. to R. I. and Ala., 111., Iowa and Mo. 



Local throughout most of the area, most common on the coastal 

 plain; not definitely recorded from Pa. 



The recently published revision of this genus by A. Beguinot and N. Bcloserky 

 records several other species within the range. 



Amsonia Amsonia (L.) Britton was found in a field at Ridgewood, Bergen Co., 

 X. J. in 1901, also collected at Lawrence, L. I. 



ASCLEPIADACEAE 



Erect or decumbent herbs. 



Corona-hoods each with an incurved horn within; leaves mostly 



opposite. I. Asclepias. 



Corona-hoods unappendaged, or with a thickened, erect-like 



keel; leaves opposite or alternate. 2. Acerates. 



Twining vines. 



Anthers tipped with a scarious membrane; pollen masses pen- 

 dulous. 3. Cvnanchum. 

 Anthers merely tipped; pollen-masses horizontal. 4. Vincetoxicum. 



i. Asclepias L. 



Flowers yellow or orange; leaves alternate or opposite. 

 Flowers not yellow nor orange. 



Corolla bright red or purple; leaves opposite. 



Flowers 8-12 mm. broad; corona-hoods 4-6 mm. high. 

 Leaves lanceolate or linear; hoods oblong, obtuse. 

 Leaves ovate or ovate-lanceolate; hoods lanceolate. 

 Leaves oblong, ovate or ovate-oblong; hoods 

 oblong, acutish. 

 Flowers 4-6 mm. broad; corona-hoods 2-3 mm. high. 

 Essentially glabrous; leaves lanceolate. 

 Pubescent; leaves oblong. 

 Corolla greenish, purplish, yellowish or white. 

 Leaves not narrowly linear. 



Plants glabrous throughout. 



Leaves sessile, clasping or very short petioled. 

 Leaves cordate-clasping. 

 Leaves rounded at the base, short-petioled. 

 Leaves manifestly petioled. 



Corolla greenish; umbels loose. 



1. A. tuberosa. 



2. A. lanceolata. 



3. .4. rubra. 



4. A. purpurascens. 



5. A. incarnata. 



6. A. pulchra. 



7. A. amplexicaulis. 



8. A. intermedia. 



9. A. exaltala. 



