224 American Midland Naturalist Monograph No. 7 



4. Leaves linear-oblanceolate, 2-6 mm wide; cymes conipact, 

 the pedicels 2-4 mm long; corolla-lobes puberulent 

 within; sepals much longer than the capsule; thin soil on 

 wooded ridges and slopes, locally in the n. counties. 



May-July H. longifolia Gaertn. 



4. Leaves linear, 1-3 mm wide; cymes loose, the filiform pedi- 

 cels mostly 4-12 mm long; corolla-lobes short-villosulous 

 within; sepals only slightly longer than the capsule; rocky 



woods, s. 111. May-July H. tenidjolia Nutt. 



2. Sepals subulate, shorter than the calyx-tube and the capsule; 

 leaves narrowly linear, many of them fascicled; capsules 

 slightly longer than broad ; blufTs and ledges in the s. and s.w. 



coimties, not common. \H. angustifolia Miclix.] 



H. nigricans (Lam.) Fern. 



1. Flowers solitary; stems very slender, 1-5 (-15) cm tall. 



5. Pedicels mostly 2-5 cm long; flowers 8-15 mm long, with a 

 yellow center, the corolla-tube more than twice the length of 

 the calyx; plants perennial with a filiform rhizome; fields and 



open woods, locally in the e. and s. counties. Apr.-June 



- H. caerulea L. 



5. Pedicels mostly 0.5-2 cm long; flowers 6-9 mm long, the corolla- 

 tube not more than twice the length of the calyx; plants 

 annual. 

 6. Calyx about half the length of the corolla-tube; hillsides and 



bluflfs, s. 111. Apr.-May. [H. patens Ell.] ....//. pusilla Schoepf 

 6. Calyx nearly as long as the corolla-tube; diy ground in the w. 

 and s. counties. Apr.-May H. minima Beck 



2. Cephalanthus L. — Buttonbush 



C. occidentalis L. Along streams and lake shores, and in swamps, 

 common throughout 111. June-Aug. Var. puhescens Raf., with twigs 

 and lower surface of leaves softly pubescent, is found occasionally in 

 s. 111. 



3. Mitchella L. — Partridge-berry 



M. repens L. In rocky woods or on sandstone ledges, local. May- 

 .July. 



4. Diodia L. — Buttonweed 



1. Leaves elliptic-lanceolate, 6-16 mm wide; corolla about 1 cm 

 long; style 2-parted; fruit ellipsoid, 7-9 mm long, strongly fur- 

 rowed, tipped with 2 slender calyx-teeth; wet ground in woods, 

 s. 111. June-Aug D. virginiajia L. 



1. Leaves linear-lanceolate, rigid, rough, 3-6 mm wide; corolla 4-6 

 mm long; style undivided; fruit turbinate, 4-5 mm long, 

 tipped with 4 short calyx-teeth; fields, roadsides, and open 

 woods nearly throughout 111. July-Aug. Rough Buttonwood 

 D. teres Walt. 



