2-3 mm. high, the outer surface conspicuously and densely cellular-papillose. 



On seepage slopes and in bogs and wet savannahs, in water of borrow-pits, 

 and along wooded streams, in e. Tex., June-Oct.; from Fla. to Tex., n. to s.e. Va. 



Fam. 108. Gentianaceae Juss. Gentian Family 



Annual or perennial herbs, glabrous or essentially so, with simple exstipulate 

 entire opposite, whorled or rarely alternate sessile to occasionally long-petioled 

 leaves; flowers solitary or borne in clusters or in simple or compound cymes, 4- to 

 12-merous, regular, perfect, hypogynous, sympetalous; calyx persistent; corolla 

 tubular, salverform, campanulate or rotate; stamens on the corolla tube, alternate 

 and as many as the lobes; ovary 1 -celled or essentially 2-celled by intrusion of 

 2 parietal placentae; style elongate to obsolete, the stigma entire to prominently 

 2-cIeft; capsule usually 2-valved and septicidal, many-seeded. 



A large world-wide family of about 80 genera and 900 species, mostly in tem- 

 perate regions. By many authors segregated into 2 families, in which case the 

 genus Nymphoides, because of its alternate leaves and valvate aestivation, is placed 

 in the Menyanthaceae. 



1. Leaves alternate, the petiole usually much longer than the floating blade; 

 corolla lobes valvate in bud; plant aquatic 9. Nymphoides 



1. Leaves opposite or whorled, rarely alternate, sessile or with petiole much 



shorter than the blade; corolla lobes never valvate in bud; plants in 

 wet habitats but not aquatic (2) 



2(1). Corolla lobes imbricate in bud, without appendages or glands; leaves 

 reduced to opposite or alternate scales 8. Bartonia 



2. Corolla lobes convolute in bud, with or without appendages or glands; leaves 



ample, opposite or sometimes whorled (3) 



3(2). Style filiform, usually deciduous from capsule; anthers either twisted or 

 prominently curved in age (4) 



3. Style usually stout and persistent, rarely obsolete; anthers remaining straight 



or only slightly curved (6) 



4(3). Stigmas linear or nearly so, about as long as the style; corolla rotate, the 

 tube conspicuously shorter than the lobes; anthers merely recurved 

 or revolute 1- Sabatia. 



4. Stigmas roundish, much shorter than the style (5) 



5(4). Corolla salverform, the tube surpassing the calyx and exceeding or equal 



in length to the lobes; anthers more or less spirally twisted 



2. Centaurium 



5. Corolla deeply campanulate, the tube much shorter than the calyx and the 



lobes; anthers straight or only slightly recurved 3. Eiistoma 



6(3). Corolla rotate the small tube much shorter than the lobes or the calyx 

 lobes (7) 



6. Corolla tubular to funnelform or campanulate, the usually well-developed tube 



as long as or longer than the lobes and calyx lobes (8) 



7(6). Style well-developed 7. Swertia 



7. Style none, the stigmas decurrent along the sides of the ovary 



5. Lomatogonium 



8(6). Corolla not spurred at base 4. Gentiana 



8. Corolla of well-developed flowers 4-spurred at base 6. Halenia 



1312 



