GENTIANACEAE 925 



entire or fringed. Androecium of as many stamens as there are corolla-lobes and 

 alternate with them, partially adnate to the corolla-tube or in the throat. Fila- 

 ments filiform or dilated at the base. Anthers erect or versatile. Gynoecium 

 compound. Ovary 1-celled, superior, with two parietal more or less in- 

 truded placentae. Styles mostly united. Stigmas 2, distinct or united. Ovules 

 numerous, inserted on the placenta or over the whole surface of the cavity of the 

 ovary, anatropous or amphitropous. Fruit a capsule. Seeds with a membra- 

 nous or crustaceous variously roughened testa. Endosperm fleshy. 



Corolla-lobes convolute in the bud : leaves present. 



Style filiform, mostly deciduous : anthers recurving or twisting at maturity. 

 Stigmas roundish, much shorter than the style. 



Corolla-tube surpassing the calyx. 1. Erythraea. 



Corolla-tube much shorter than the calyx. 2. Eustoma. 



Stigmas linear or nearly so, about as long as the style. 



Flowers ijedicelled, when more than one, paniculate : anthers coiled. 3. Sabbatia. 

 Flowers sessile, when more than one, capitate : anthers curved. 4. Lapithea. 



Style stout, short or wanting : anthers straight at maturity. 

 Corolla not furnished with nectariferous pits, glands or scales. 



Corolla without plaits in the sinuses of the lobes: calyx without an in- 

 terior membrane. 

 Sepals unequal, the inner much broader than the outer and thin- 

 margined : corolla-lobes fimbriate or erose. 5. Anthopogon. 

 Sepals essentially equal, or if unequal the inner narrower than the 



outer : corolla-lobes entire or merely toothed. 6. Gentianella. 



Corolla with plaits in the sinuses of the lobes: calyx with an inte- 

 rior membrane. 7. Dasystephana. 

 Corolla furnished with nectariferous pits, glands or scales, 1 or 2 for each 

 lobe. 

 Corolla rotate, with a fringed gland at each lobe. 8. Frasera. 

 Corolla campanulate, with spurs at the base. 9. Tetragonanthtjs. 

 Corolla-lobes imbricated in the bud : leaves, or those of the stem, reduced to scales. 

 Stigmas 2, distinct : foliage green. 



Calyx-lobes 4, narrowed upward. 10. Bartonia. 



Calyx-lobes 2, broadened upward. 11. Obolaria. 



Stigmas united, dilated : foliage white. 12. Voyria. 



1. ERYTHRAIJA Neck. 



Annual, biennial or sometimes perennial caulescent herbs. Leaves opposite : blades 

 entire, mostly sessile or clasping. Flowers in terminal cymes, often numerous. Calyx 

 pedicelled : lobes 4-5, narrow, keeled. Corolla wbite, pink, rose or yellow, salverform : 

 tube more or less elongated : lobes 4-5, spreading, convolute or contorted. Stamens 4-5, 

 partially adnate to the corolla-tube : filaments short, but filiform : anthers twisted at ma- 

 turity. Ovary 1-celled, with the placentae sometimes intruded : stigmas 2. Capsules 

 ovoid-oblong to fusiform, 2-valved. Seeds several or numerous, reticulated. Centaury. 



Corolla-lobes much less than }-i as long as the tube. 



Corolla-lobes obtuse : specie's naturalized eastward. 1. E. pulchdla. 



(;orolla-lobes acute : species native, Texan. 2. E. Texensis. 

 Corolla-lobes fully ^ as long as the tube or nearly equalling it in length. 



Corolla-lobes acute. 3. E. Beyrichii. 



Corolla-lobes obtuse. 4. E. calycosa. 



1. Erythraea pulchella (Sw. ) Fries. Stem square, 3-25 cm. tall, more or less 

 branched : leaf-blades spatulate at the base of the stem, to oblong or ovate above, usually 

 1-2 cm. long, obtuse, entire, sessile : flowers in diffuse cymes : calyx-lobes linear-subulate, 

 6-8 mm. long, unecjual in length, mostly shorter than the corolla-tube : corolla glabrous ; 

 tube greenish, 8-10 mm. long ; lobes deep pink, 5-6.5 mm. long, ovate-oblong, obtuse: 

 stamens slightly exserted : anthers lemon-yellow : capsule 7-9 mm. long, as long as the 

 calyx or longer. 



In fields and waste places. New York to Georgia. Naturalized from Europe. Summer and fall. 



2. Erythraea Tex6nsis Griseb. Stems 0.5-2 dm. tall, corymbosely branched above, 

 not diffuse : leaf-blades lanceolate to linear or subulate above, 0.5-1.5 cm. long, acute, 

 entire, sessile : calyx 8-10 mm. long ; lobes subulate : corolla light rose-colored ; tube 

 surpassing the calyx ; lobes oblong to oblong-lanceolate, acute, much shorter than the tube : 

 capsule surjDassing the calyx. 



In rocky soil, Texas. Spring. 



3. Erythraea Beyrichii T. & G. Stems erect, or branched at the base, the branches 

 ascending, 0.5-2 dm. long, often densely branched above the middle : leaf-blades linear- 

 spatulate to linear, usually narrowly so, 1-2.5 cm. long, acute, thelower onesslender-petioled : 

 calyx 8-10 mm. long ; lobes setaceous-subulate : corolla deep pink ; lobes oblong-lanceo- 



