256 RUBIACEAE, Vou. III. 
5. SPERMACOCE L. Sp. Pl. 102. 1753. 
Herbs, with 4-sided stems, opposite pinnately veined stipulate leaves, and small white 
flowers, in dense axillary and terminal clusters. Calyx-tube obovoid or obconic, its limb 
4-toothed. Corolla funnelform, 4-lobed. Stamens 4, inserted on the tube of the corolla; 
anthers oblong or linear. Ovary 2-celled; ovules 1 in each cavity; style slender; stigma 
capitate, or slightly 2-lobed. Capsule coriaceous, didymous, of 2 carpels, one dehiscent, the 
other indehiscent. Seeds oblong, convex on the back; endosperm horny; embryo central; 
cotyledons foliaceous. [Greek, seed-point, from the sharp calyx-teeth surmounting the carpels.] 
Two or three species, natives of America. Type species: 
Spermacoce tenuior L. 
1. Spermacoce glabra Michx. Smooth Button- 
weed. Fig. 3925. 
Spermacoce glabra Michx. Fl. Bor. Am. 1: 82. 1803. 
Glabrous, decumbent or ascending, rather stout; stems 
10-20’ long. Leaves lanceolate or elliptic-lanceolate, peti- 
oled, or the uppermost sessile, 1’-3’ long, 4’"-12” wide, acute 
_at each end, the margins rough; corolla pubescent in the 
throat, about 14” long, scarcely exceeding the ovate-lanceo- 
late acute calyx teeth; stamens and style included; capsule 
obovoid, about 2” long, glabrous; seeds black, punctate. 
On river-banks and in wet soil, southern Ohio and Ken- 
tucky to Florida, Kansas and Texas. June—Sept. 
6. DIODIA L. Sp, Pl.tog. a75g, 
Decumbent or ascending branching herbs, with opposite, mostly sessile, entire conspicu- 
ously stipulate leaves, and small axillary white lilac or purple flowers. Calyx-tube obconic 
or obovoid, the limb 2-4-lobed (sometimes 1-6-lobed), often with minute teeth between the 
lobes. Corolla funnelform or salverform, mostly 4-lobed. Stamens usually 4, inserted on 
the throat of the corolla; filaments slender; anthers versatile, oblong-linear, exserted. Ovary 
a-celled (rarely 3-4-celled) ; ovules 1 in each cavity; style filiform, simple or 2-cleft; stigmas 
2. Fruit crustaceous or somewhat fleshy, oblong, obovoid, or subglobose, 2-celled, finally 
separating into 2 indehiscent carpels. Seeds oblong, convex on the back; endosperm horny; 
cotylendons foliaceous; embryo straight. [Greek, thoroughfare, where the species are fre- 
quently found.] 
About 35 species, mostly American. Besides the following, another occurs in the Southern 
States. Type species: Diodia virginiana L. 
Leaves linear-lanceolate ; style entire; stigmas capitate. 1. D. teres. | 
Leaves lanceolate or oval; style 2-cleft; stigmas filiform. 2. D. virginiana. 
Fig. 3920. 
f Lg 
1. Diodia téres Walt. Rough Button-weed. N; \\ Wi 
MZ 
Diodia teres Walt. Fl. Car. 87. 1788. 
Spermacoce diodina Michx. Fl. Bor. Am. 1: 82. 1803. 
Rigid, usually rough, much branched from near the 
base, the branches prostrate or ascending, 4-sided above, 
4-30’ long. Leaves linear or linear-lanceolate, very 
rough, 4’-14’ long, 14-3” wide, acute, the margins revo- 
lute when dry; flowers lilac or purple, 2’’-3” long, usually 
solitary in the axils; style entire; stigmas capitate; fruit 
obovoid or top-shaped, hispid, about 2” high, the usually 
4 persistent calyx-lobes ovate to lanceolate. 
In dry or sandy soil, Connecticut to Florida, west to 
Illinois, Kansas, Texas, New Mexico and Sonora. July- 
Sept. Poverty-, or poor-land-weed. Poor Joe. 
