402 ORDER 67. RUBIACE^E. 



6. DIO'DIA L. (Gr. &$, twice, odovg, tooth, alluding to the two 

 calyx teeth crowning the ovary.) Calyx, corolla, stamens, style and 

 fruit as in the next genus (Spermacoce) except that the (2 or 3) 1 -seeded, 

 separable carpels are in both indehiscent ; seeds oval, peltate. American, 

 chiefly tropical herbs. Stip. fringed with bristles. Fls. small, white, 

 axillary, sessile, solitary or few. 



1 D. Virginiana L. Procumbent, nearly glabrous or hirsute ; sts. squarish ; Ivs- 

 lanceolate, sessile, entire ; bristles of the stip. longer than the sheaths ; fls. soli- 

 tary, opposite ; cor. salver form, tube very slender, thrice larger than the cal. ; 

 stem, exserted; style deeply 2-cleft, lobes filiform. if Damp places, 111. to Ga. 

 and La. St. 1 to 2f long, somewhat 4-sided. Lvs. 1 to 2' by 3 to 5", 1-veined, 

 often with smaller ones fascicled in the axils. Cor. 6" long, hairy inside. May- 

 September. 



(3. has ovate-lanceolate Irs. (D. tetragona TValt.) 



y. has lance-linear, hairy Ivs, ; cor. 6" long. May Sept. (D. hirsuta Ph.) 



2 D. terea "Walt. Erect or ascending, hairy or scabrous ; Ivs. linear-lanceolate, 

 sessile, rough-edged, acute, much longer than the sheaths or fruit ; fls. solitary, or 

 several in each axil ; cor. funnel-form, with a wide tube, twice longer than the cal. ; 

 fl. somewhat hairy and 4-sided. Sandy fields, N. J. to 111. (Mead) and S. States. 

 Sts. rather rigid, simple, or branched, 5 to 18' long, brownish. Lvs. about 1' by 

 2". Cor. reddish white, shorter than the reddish brown bristles. Aug., Sept 

 (Spermacoce diodina MX.) 



7. SPERMACO V CE, L. (Gr. OTreppa, seed, a/cw/c?/, a point ; alluding 

 to the pointed seeds.) Calyx tube ovoid, limb 2 to 4-parted ; corolla 

 tubular, limb spreading, 4-lobed ; stamens 4 ; stigma 2-cleft ; fruit dry, 

 2-celled, crowned with the calyx, separating into 1 open and 1 indehis- 

 cent carpel ; seeds 2, peltate, furrowed on the face. Mostly herbaceous 

 and tropical. Fls. small, in dense, axillary, sessile whorls, or clusters. 



1 S. glabra MX. Glabrous, procumbent at base ; Ivs. lanceolate, entire ; whorls 

 many-flowered ; cal. 4-toothed (rarely 5) ; cor. funnel-form, short, hairy in the 

 throat ; anth. included in the tube ; stig. subsessile. If River banks, TV. States. 

 St. 1 to 2f long, terete, with 4 prominent lines, branched. Lvs. 2 to 3' by to 1', 

 tapering to each end. Fls. white, 9 to 20 in a whorl, subtended by the subulate 

 bracts of the stipules. Jl, Aug. Resembles some of the Labiata3. 



2 S. Chapmanii Torr. & Gr. Nearly glabrous ; st. slightly 4-angled ; Ivs. ob- 

 long-lanceolate, attenuate to a petiole ; whorls dense-flowered ; cor. funnel-form, 

 thrice longer than tho cal. ; stain, and slender sty. exserted. River banks, Mid. 

 Fla. (Chapman.) 



8. HOUSTCTNIA, L. BLUETS. (Dedicated to Dr. Wm. Houston, 

 the friend and correspondent of Miller.) Calyx tube ovoid-globous, 

 limb 4-toothed or cleft, persistent ; corolla tubular, much exceeding the 

 calyx ; limb 4-lobed, spreading ; filaments 4, inserted on the corolla ; 

 style 1 ; anthers and stigmas dimorphous, that is, in some plants, the 

 former exserted and the latter included, in others the style exserted and 

 anthers included ; capsule 2-lobed, the upper half free, cells few (8 to 

 20)-seeded. Herbs. Stip. connate with the petiole, entire. Fls. soli- 

 tary or in cymes, white, purplish, or bluish. 



Corolla salver-form, glabrous. Peduncles 1-floweretl terminal ................. Nos. 1,2 



axillary .................. -Nos 3, 4 



Corolla funnel-form. Peduncles 00 -flowered, cymous. Leaves lance-ovate ......... No. 5 



Leaves lance-linear ..... Nos. 6, 1 



1 H. ccerulea L. DWARF PINK. INXOCEVCE. Caespitous; radical Ivs. ovate- 

 spatulate, petiolate ; sts. erect, numerous, dichotomous L pod. filiform, 1 to 2 -flow- 

 ered. (g) An elegant little plant found in moist grounds, fields, and road-sides, 

 Canada and U. S., often in patches. Caulino Ivs. very small, opposite, lance- 



