204 American Midland Naturalist Monograph No. 2 



2. Samara 5-7 cm. long, about 1 cm. wide, the body flattened; calyx 3-6 



mm. long; leaflets usually entire, the lower surface light green; leaf- 

 scars deeply notched at the top; wet ground, locally in s. 111., and 

 northw. to St. Clair, Richland, and Lawrence counties. Pumpkin Ash. 



[F. profunda (Bush) Britt.] F. tomentosa Michx. f. 



1. Petioles glabrous or nearly so; twigs glabrous. 



3. Calyx evident on the fruit; body of the samara terete or nearly so; 



leaflets 5-9, commonly 7, usually more or less petiolulate; twigs terete. 

 4. Wing of the samara almost entirely terminal; leaflets ovate-lanceolate 

 or oval, entire or nearly so, glabrous beneath or pubescent; leaf- 

 scars deeply notched at the top; woods, common throughout 111. 

 White Ash. This species has sometimes been mistaken for F. bilt- 



moreajia Beadle, which apparently does not occur in III. 



_ F . americana L. 



4. Wing extending down the sides of the samara; leaflets elliptic-lanceo- 



late, usually serrate, acuminate at each end, glabrous; leaf-scars near- 

 ly straight at the top; low woods, and along roads, common. Green 



Ash F. laiiceolata Borkh. 



3. Calyx none or minute; body of the samara flattened, the wing decurrent; 

 leaflets 7-11. 



5. Twigs terete; leaf -scars vertically oval; lateral leaflets sessile; flowers 



polygamous; wet ground, local. Black Ash. \F. famhucifolia Lam.] 



F. nigra Marsh. 



5. Twigs usually prominently quadrangular; leaf-scars lunate; lateral leaf- 

 lets shortly petiolulate; flowers perfect; woods, local; chiefly through 

 central 111. Blue Ash F. quadrangulata Michx. 



2. Forestiera Poir. 



{Adelia P.Br.) 



F. acuminata Poir. River banks and swamps, s. 111.; extending northw. to 

 Wabash and Lawrence counties, and in w. III. to Fulton Co. Apr. -May. 



126. Gentianaceae Dum. — 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 I. Ceniaurium 



4. Corolla rotate; stigmas linear 2. Sahaiia 



3. Style short or none; anthers straight; corolla funnelform or salverform, without 



glands 3. Ccntiana 



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. Darionia 



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



1. Centaurium Hill — Centaury 

 C. pulchellum (Sw.) Druce. Wet ground, nat. from Eur. June-Sept. 



