218 



RUBIACEAE. 



[Vol.. III. 



2. Diodia Virginiana L. Larger 

 Button- weed. (Fig. 3107.) 



Diodia Virginiana L. Sp. PI. 104. 1753. 



Hispid-pubescent or glabrate, much 

 branched from near the base, the branches 

 procumbent or ascending, i-2 long. 

 Leaves lanceolate to narrowly oval, nar- 

 rowed at the base, acute, or the lowest ob- 

 tuse at the apex, i / -3 / long; flowers 1 or 2 

 in each axil, about 6 /7 long, the corolla-tube 

 very slender; fruit somewhat fleshy, but 

 becoming dry, hirsute or glabrous, oval, 

 3 // -4 // high, furrowed, crowned with the 2 

 or 3 persistent lanceolate calyx-lobes. 



In moist soil, southern New Jersey to Flor- 

 ida, west to Arkansas and Texas. June-Aug. 



7. GALIUM L. Sp. PI. 105. 1753. 



Annual or perennial herbs, with 4-angled slender stems and branches, apparently verti- 

 cil late leaves, and small white green yellow or purple flowers, mostly in axillary or termi- 

 nal cymes or panicles, the pedicels usually jointed with the calyx. Flowers perfect, or in 

 some species dioecious. Calyx-tube ovoid or globose, the limb minutely toothed, or none. 

 Corolla rotate, 4-lobed (rarely 3-lobed). Stamens 4, rarely 3; filaments short; anthers ex- 

 serted. Ovary 2-celled; ovules 1 in each cavity. Styles 2, short; stigmas capitate. Fruit 

 didymous, dry or fleshy, smooth, tuberculate, or hispid, separating into 2 indehiscent car- 

 pels, or sometimes only 1 of the carpels maturing. Seed convex on the back, concave on 

 the face, or spherical and hollow; endosperm horny; embryo curved; cotyledons foliaceous. 

 [Greek, milk, from the use of G. verum for curdling.] 



About 225 species, of wide geographic distribution. Besides the following, about 27 others 

 occur in the southern and western parts of North America. The leaves are really opposite, the in- 

 tervening members of the verticils being stipules. 



& Fruit dry, smooth, hispid or roughened. 



t Annuals, (except No. 1.) 

 1. Flowers yellow; leaves narrowly linear. 1. G. verum. 

 2. Flowers white or greenish white. 



a. Fruit smooth and glabrous. 2. G. Mollugo. 



b. Fruit bristly, tubercled or papillose. 

 Flowers in axillary cymules, or panicled. 

 Fruit granular or tubercled, not bristly. 



Fruit slightly granular, or smooth, %" broad; pedicels not recurved; 



stem very slender. 3. G. Parisiense. 



Fruit granular-tubercled, i l A" broad: fruiting pedicels recurved; stem stout. 



4. G. tricorne. 

 Fruit densely bristly-hispid. 



Cymes few-flowered; leaves 1'-$' long; fruit fully 2" broad. 5. G. Aparine. 



Cymes mostly several-flowered; leaves %'-i' long; fruit smaller. 6. G. spurium. 

 Flowers solitary in the axils, subtended by 2 foliaceous bracts; fruit bristly. 7. G. virgatum. 



t t Perennials. 

 1. Fruit bristly-hispid (or becoming glabrous in no. 12). 



a. Leaves in 4's, i-nerved. 8. G pilosum. 



b. Leaves in 4's, 3-nerved. 

 Leaves lanceolate, oval, or ovate; flowers in open cymes. 



Ipper leaves lanceolate to ovate-lanceolate, acuminate. 9. G. lanceola/um. 



Upper leaves ovate, oblong, oval, ovate-lanceolate or obovate, obtuse. 



Corolla usually hirsute; plant mostly pubescent; leaves oblong to ovate-lanceolate. 



10. G circaezans. 

 Corolla glabrous; plant little pubescent; some leaves obovate. 11. 

 Leaves linear to lanceolate; flowers in terminal panicles. 12. 



C. Leaves in 6's. 13. 



2. Fruit smooth and glabrous (warty in no. 15). 

 a. Flowers brown-purple. 

 Leaves lanceolate, 3-nerved; fruit smooth. 

 Leaves narrowly lanceolate, i-nerved; fruit warty. 



b. Flowers white, yellowish, or greenish. 

 Endosperm of seed annular in cross-section. 



Corolla 4-parted, its lobes acute; stems smooth, or nearly so. 



Corolla mostly 3-parted, its lobes obtuse; stems minutely retrorse-hispid. 



Pedicels slender, rough; leaves mostly in 4's. 17. G. trifidum. 



Pedicels rather stout, smooth; leaves mostly in 5's and 6's. 18. G. Clayton 1. 



G. k'a m Iscli a I ic u m . 

 G boreale. 

 G. triflorum. 



14. G. latifolium. 



15. G. Arkansanum. 



16. G tinctorium. 



