Jones: Flora of Illinois, 145. Rubiaceae 235 



1 . Leaves linear. 



6. Capsules 4-seeded; calyx-lobes erect and converging over the top of the 

 capsule; stamens 2; fields, roadsides, and open woods, chiefly in the s. 



half of the state. Apr.-May P. pusitla Nutt. 



6. Capsules 2-seeded; calyx-lobes spreading or reflexed in fruit, not closed 

 over the top of the capsule. 

 7. Bracts much longer than the flowers; fields, roadsides, and open woods, 



common. June-Aug. Bracted Plantain P. aristata Michx. 



7. Bracts not longer than the flowers; sandy soil in fields and along roads, 

 n. 111., local. May-Aug P. piirshii R. &: S. 



145. Rubiaceae B. Juss. — Madder Family 



1. Shrubs; leaves opposite or whorled; flowers in dense globose heads 2. Cephalanlhus 



I. Herbs. 



2. Leaves opposite. 



3. Flowers axillary, sessile or nearly so. 



4. Plants pubescent; fruit separating into 2 or 3 indehiscenf carpels 4. Diodia 



4. Plants glabrous; fruit a capsule of 2 carpels, one dehiscent, the other inde- 



hiscenl 5. Spermacoce 



3. Flowers pedicellate, cymose or solitary. 



5. Plants trailing; leaves evergreen, cordate at base; fruit a pair of united red 



drupes 3. Mitchella 



5. Plants erect; leaves not as above; fruit a capsule 1. Homlonia 



2. Leaves apparently in whorls of 4-8 6. Calium 



1. HousTONiA L. — Bluets 



1. Flowers cymose; stems 10-50 cm. tall; plants perennial. 



2. Calyx-lobes much exceeding the capsule, and about twice as long as the 

 calyx-tube; stem-leaves lanceolate to linear-lanceolate; open rocky woods, 

 local; chiefly in the centr. and s. parts of III., but also in Will and La 

 Salle counties; May-July. [H. purpurea var. calycosa Gray; H. pur- 

 purea of III. reports} H. lanceolata (Poir.) Britt. 



2. Calyx-lobes slightly if at all exceeding the capsule, about as long as the 



calyx-tube; stem-leaves linear or linear-oblanceolate; thin soil on wooded 

 ridges and slopes, rare; s. 111., northw. to Jackson, Williamson, and 

 Saline counties. May-July H. longijolia Gaertn. 



1. Flowers solitary; stems very slender, 1-5 (-10) cm. tall. 



3. Pedicels mostly 2-5 cm. long; flowers with a yellow center; plants peren- 



nial with a filiform rhizome; fields andopen woods, local; known from 



Cook, Kankakee, St. Clair, and Johnson counties. Apr.-June 



H. caerulea L. 



3. Pedicels mostly 0.5-2 cm. long; flowers without a yellow center; plants 

 annual; dry ground, rare. Apr.-May. Truro, Knox Co., May 10, 1908, 

 V. H. Chase 1632 H. minima Beck 



2. Cephalanthus L. — Buttonbush 



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

 throughout III. June-Aug. 



