186 American Midland Naturalist Monograph No. 7 



2. Asclepiodora A.Gray — Spider Milkweed 

 A viridis (Walt.) A.Gray- Di-y soil, not common; s. 111., northward 

 to Bond and Fayette counties. June-July. 



3. Ampelamus Raf. — Bluevine 

 A. alhidus (Nutt.) Britt. River banks and thickets, or along 

 fences; chiefly in the southern half of the state, but extending north- 

 ward to Vermilion, Champaign, Putnam, and Heni^y counties. July- 

 Aug. [Gonolobus laevis sensu auth., non Michx.]. 



4. Gonolobus Michx. — Climbing Milkweed 



1. Flowers greenish-yellow; pedicels glabrous; follicles angular, 

 smooth, glabrous; along fences and in open woods; Alexander, 

 Hardin, Pulaski, and Union counties. June-July. [Vincctoxi- 

 cum gonocarpos Walt.] G. gonocarpos (Walt.) Perry 



1. Flowers reddish-purple; pedicels pubescent; follicles pubescent, 

 muricate; woods; Pope Co., G. H. Boewe. July-Aug. [Vince- 

 toxician obliquum (Jacq.) Britt.; Matclea obliqua (Jacq.) 

 Woodson] G. obliquus (Jacq.) R.Br. 



5. Cynanchum L. 



C. nigrum (L.) Pers. Waste places; escaped from gardens; introd. 

 from Eiu\ 



101. Loganiaceae Dumort. — Logania Family 



1. Spigelia L. — Indian Pink 

 S. marilandica L. Woods and thickets in s. 111., extending north- 

 ward to Jefferson Co. May-Jime. 



102. Gentianaceae Dumort. — Gentian Family 



1. Leaves not scale-like. 

 2. Leaves opposite. 



3. Style filiform, mostly deciduous; anthers becoming twisted or revolute 

 at maturity. 



4. Corolla salverform; stigmas roundish 1. Centaurium 



4. Corolla rotate; stigmas linear 2. Sabatia 



3. Style short or none; anthers straight; corolla funnelform or salverform, 

 without glands 3. Gentiana 



2. Leaves whorled ; stem 1-3 m tall; anthers straight; corolla rotate, with 

 4 lobes and 1 or 2 nectariferous glands for each lobe 4. Frasera 



1. Leaves (at least the lower) reduced to scales; stem slender or filiform. 



5. Calyx-lobes 4; corolla 3-4 mm long; leaves all reduced to scales 



5. Bartonia 



5. Calyx-lobes 2; corolla about 1 cm long; upper leaves normal ....6. Obolaria 



