Acerates 



ASCLEPIADACEAE 



765 



50 



Map 1641 



Apocynum sibincum Jacq 



Miles 



50 



Map 1642 

 Apocynum sibincum 

 var. Farwelln (Greene) Fern. 



50 



Map 1643 



Acerates hirtella Pennel 



1. Acerates hirtella Pennell. (Bull. Torrey Bot. Club 46: 184-185. 

 1919.) (Acerates floridana (Lam.) Hitchc, in part, of Gray, Man., ed. 7 

 and Britton and Brown, Illus. Flora, ed. 2.) Map 1643. In sandy soil along 

 roadsides and railroads and in fallow fields. Infrequent in the lake area 

 and in the western part of the state. Mostly in prairie habitats. 



Mississippi Valley, range not determined ; probably from Mich, southw. 

 and westw. to Okla. 



2. Acerates viridiflora (Raf.) Eaton. Map 1644. In sandy soil along 

 roadsides and railroads and in fallow fields. It prefers sandy soil and is 

 apparently a prairie plant but it is sporadic in the southern part of the 

 state. 



Acerates viridiflora var. lanceolata (Ives) Gray is a variety which has 

 been reported from Indiana but which I am referring to the species, as 

 some authors do, because I am not able to separate the two. I have one speci- 

 men with some of the leaves 5 cm wide and one specimen with leaves 8 mm 

 or less in width, and other specimens with leaves that connect these 

 extremes. Since the width of the leaves is the only distinguishing char- 

 acter, it is best to consider the species as one with variable foliage. A 

 very narrowleaf form occurs on the low dunes in west Gary, Lake County. 



Ohio and Ont. to Minn., southw. to Fla. and Tex. 



6791. ASCLIilPIAS L. Milkweed 



,1. A. verticillata. 



Leaves filiform-linear, mostly in whorls of 3-6; flowers white 



Leaves not as above. 

 Leaves alternate or a few opposite; flowers orange, sometimes very pale orange or 



rose color 2. A. tuberosa. 



Leaves opposite or sometimes in nos. 3 and 7 with 1 or 2 whorls of 3 or 4 leaves. 

 Leaves sessile or clasping, broad and cordate at the base. 



Blades rather small, the median and upper pairs rarely more than 7 cm long, 

 ovate to lanceolate, gradually tapering from below the middle to an acute 

 apex, flat, 3 or 4 pairs, rarely a whorl, the margins scabrous; umbels termi- 



