306 LXXII. RUBIACEiE. Spermacoce. 



§ Corolla hypocratemform, with a long tube, limb glabrous. Peduncles 

 l-Jlower-ed. Houstonia. Linn. 



1. H. ccERULEA. Hook. (Hous. coerulea. Linn.) Dwarf Pink. Innocence. 

 Radical Ivs. ovate-spatulate, petiolate ; sts. erect, numerous, dichotomous ; 



ped. filiform, 1— 2-flowered.— An elegant little plant, found in moist grounds, 

 fields and road-sides. Can. and U. S. Its blossoms appear early, and are usu- 

 ally found in patches of considerable extent, covering the surface of the ground 

 ■with a ccerulean hue. The cauline leaves are small, opposite, lance-ovate. 

 Stems very slender, forked, 3 — 5' high, each branch bearing a flower. Corolla 

 pale blue, yellowish at the centre. May — Aug. 



2. H. MINIMA. T. & G. (Houstonia. Beck.) 



Glabrous, simple or dichotomously branching ; Ivs. linear-spaiulate, much 

 attenuated to the base ; ped. axillary and terminal, often longer than the leaves ; 

 sds. 10 — 15 in each cell, oval, smooth, concave on the face. — Prairies, &c., Mo. ! 

 Tenn. ! to La. Very small and delicate, 1—3' high. Leaves about 5" by I". 

 Flowers rose-color. Mar. — May. 

 § § Corolla infundilndiform, often hairy inside. Flowers in terminal 

 racemes. Amphiotis. DC. 



3. H. ciLiOLATA. Torr. (Hous. Canadensis. Muhl.) Clustered Dwarf Pink, 

 Radical Ivs. ovate, obtuse, narrow at the base, ciliate on the margin ; cau- 

 line ones ovate-spatulate, sessile ; corymbs terminal, pedicellate ; ped. tricho- 

 tomous ; divisions of the calyx lance-linear. — Banks of lakes and rivers, Onta- 

 rio ! Niagara ! W. to Ohio. A little plant, stouter than the last. Root-leaves 

 numerous, stem-leaves few. Stems smooth, 4-angled, branched above, and 

 bearing a corymbose cluster of numerous pale purple flowers. Calyx half-ad- 

 herent, its lobes about half as long as the tube of the corolla. May— July. 



4. H. LONGiPOLiA. Hook. ("Houstonia longif. Gaert.) Long-leaved Dwarf 

 Pink.— Radical Ivs. oval-elliptic, narrowed to each end ; cauline linear or 



lance-linear, 1-veined ; p. in small, paniculate cymes.— 'Zj. Diy hills, N. and 

 Mid. States ! to Ark. and Flor. Much more slender than the next. Stems 

 erect, 5 — 12' high, 4-angled, smooth or ciliolate on the angles. Leaves 9 — 15" 

 ]3y 2-^3", cauline sessile, rather acute at each end, all smooth. Flowers 2 or 3 

 together, on very short pedicels, pale-purple, with deeper-colored striae in the 

 throat. Jn. Jl. 



0.'\ (H. tenuifolia. Nutt.) St. very branching ; Ivs. very narrow; ^e<^. fili- 

 form ; fls. smaller. 



5. H. PURPUREA. Torr: & Gray. (Houstonia. Linn.) 



St. ascending, clustered, branching, 4-angled ; Ivs. ovate-lanceolate, 3 — 5- 

 veined, closely sessile; cyiiies 3— 7-flowered, often clustered; calyx segments 

 lance-linear, longer than the capsule. — Mid. and W. States ! in woods and on 

 river banks. A very delicate flowerer, about If high. Leaves 1 — 2' long, ^ as 

 wide. Corolla (purple, T. <f- G.) white, scarcely tinged with purple. May— Jl. 

 § § § Corolla rotate, tube very short. Seeds 50 — 60 in each cell. Flowers 

 mostly glomerate in the axils of the leaves. Elatinella. Torr. <^ Gray. 



6. H. GLOMERATA.. Creeping Greoi-head. 



St. assurgent, branching; lis. oblong-lanceolate, pubescent, narrowed at 

 the base into a short petiole or sessile ; fis. glomerate in the axils and terminal: 

 A plant varying in size from 1 — 2' to as many feet, found in swamps, &c., N. 

 Y. to La. Leaves ^' in length, apparently connate from the stipules adhering 

 to each side of the petiole. Stipules 2-cleft into narrow subulate divisions. 

 Calyx in 4 deep, leafy divisions which are much longer than the white, rotate 

 corolla. Stamens scarcely exserted. Style very short. Capsule opening cross- 

 wise. Jn. — Sept. 



4. SPERMACOCE. 

 Gt. (TTTEpfia, seedj uKiOKri, a point; alluding to the pointed seeds. 



Calyx tube ovoid, limb 2 — 4-parted ; corolla tubular, limb spread- 

 ing, 4-lobed ; stamens 4 ; stigma 2-cleft ; fruit dry, 2-celledj crowned 



