500 TRANS. ST. LOUIS ACAD. SCIENCE. 



+ + ++ Stem pubescent. 

 B. Canadensis, L. Spec. 



Open ground, roadsides, moist woods, etc.; common. 



Resembles S. serotina in general appearance, but stem, and usually smaller and 

 narrower leaves, pubescent. 



Var. PBOCEBA, (Ait.) Torr. & Gray, Fl. ii. p. 224.— >S'. proccra, 

 Ait. Hort. Kew. 



Open ground ; not uncommon. 



Plant paler, leaves less serrate, and panicle much smaller than in S. Canadensis. 



S. NEMORAL1S, Ait. Hort. Kew. 

 Dry gravelly soil ; abundant. 



Stem (a few inches to 2 feet high) cinereous-pubescent; leaves spatulate or ob- 

 lanceolate, entire, or the lower sparingly serrate; panicle recurved, or in the taller 

 specimens sometimes erect. 



* * * Heads disposed in corymbiform or cymose clusters. 

 ■*- Stem densely pubescent. 



B. RIGIDA, L. Spec. 



Prairie; common. 



Stem 2 to 3 feet high, softly pubescent or scabrous; radical leaves on long peti- 

 oles; lower cauline. oblanceolate tapering into slender petioles; upper, ovate to ob- 

 long, sessile; all entire or nearly so. 



4- ■»- Stem nearly or quite glabrous. 



S. Riddell.ii, Frank, in Riddell, Synops. 1835. 



Sloughs, often growing in the water; infrequent. 



Low prairie north of Ames, and elsewhere. Stem smooth, i to 2 ft. high; leaves 

 entire, long and narrow, erect from a sheathing base. 



S. graminifolia, (L.) Ell. Sk. ii. — Chrysocoma g r am in i folia, L. 

 Spec. — 5. lanceolata, L. Mam. p. 114. 

 Wet places; abundant. 



Stem much branched, usually smooth, 1 to 3 feet high, with long and slender 

 rootstocks; leaves narrowly lanceolate, 3-nerved , heads glomerate -sessile. Flow- 

 ering late. 



Bolton ia asteroides, (L.) L'Her. Sert. Angl. 11 §§.— Matricaria 

 asteroides. L. Mant. p. n6. 

 Sloughs ; frequent. 



This has the general appearance of an Aster, but the pappus consists of two 

 (under a lens, setose) awns and a ring of short bristles; the achene is setulosc en 

 the upper part of its winged margin. 



Aster oblongifolius, Nutt., var. rigidulus, Gray, Syn. Fl. i. 2. 



Rocky bluffs ; infrequent. 

 A. No\m:-An<;li.k, L. Spec. 



Sloughs and moist places; abundant. 



Var. boseus, (Desf.) DC. Prod, v*— A. roscus, Best. Cat. H. Par. 



3 d ed. 



With the above; an infrequent form. 

 A. 3ERICEUS, Vent. Hort. Cels. 1800. 

 Dry banks : infreq 



