KEY TO FAMILIES. 15 



Corolla-tube without internal scales or appendages; style 1 or none; 



stigmas 1 or 2. 



Ovary and capsule 1-celled; flowers 4 or 5-merous; leaves simple and 



opposite, or 3-foliolate and alternate. .. . Gextiaxaceae, p. 319. 



Ovary 2-celled; fruit commonly 2-celled; stamens 5; leaves alternate. 



Leafless parasitic twining plants Cuscuta, p. 327. 



Leafy plants. 



Corolla with 5 lengthwise folds and twisted in the bud; calyx of 

 5 distinct sepals; capsule 1 to 4-seeded 



COXVOLVULACEAE, p. 324. 



Corolla imbricate or valvate in bud and mostly plicate; calyx 5- 



cleft or -toothed; capsule many seeded. .Solaxaceae, p. 365. 



Ovary 2 or 4-celled; capsule circumscissile; corolla scarious; stamens 2 



or 4; style 1; acaulescent herbs Plaxtagixaceae, p. 390. 



Ovary 3-celled, the flower otherwise 5-merous; style 3-cleft or 3-lobed ; 



capsule 3-valved Polemoxiaceae, p. 328. 



Ovary 4-celled and commonly 4-lobed, splitting at maturity into as many 



nutlets; stamens 5; style 1, entire; leaves alternate (at least the 



upper) ; flowers in coiled racemes or spikes. . . . Boragixaceae, p. 344. 



Pistils 2 (the ovaries distinct but the styles or stigmas united), becoming 



follicles; leaves opposite or whorled; plants with milky juice. 



Stamens and stigmas united, the column bearing hood-like appendages. . . . 



Asclepiadaceae, p. 322. 

 Stamens and stigmas not united; no hoods Apocyxaceae, p. 321. 



j Corolla from strongly bilabiate to slightly irregular. 



Stamens 4 or 2. 



Fruit a 1-celled capsule. 



Stamens 2; corolla spurred; aquatic plants with finely divided leaves, some 



bearing bladders Utriculariaceae, p. 388. 



Stamens 4; root-parasites without green foliage. .Orobaxchaceae, p. 388. 

 Fruit a 2-celled capsule; leaves alternate or opposite; a sterile filament or 



scale rarely present as a fifth stamen Scrophulariaceae, p. 368. 



Fruit of 2 to 4 nutlets; leaves opposite. 



Ovary not lobed, 2 to 4-celled, splitting into as many nutlets; stamens 4; 



style 1, entire Verbexaceae, p. 351. 



Ovary 4-lobed, splitting into as many nutlets ; stamens 4 or 2 ; style 1, 



cleft; stems square; herbage with the odor of mint..LABiATAE, p. 352. 



Stamens 5, some or all woolly Verbakcum, p. 370. 



b. Ovary inferior, i. e., adherent to the calyx-tube. 

 Stamens distinct. 



Leaves alternate; flowers regular; stamens 5; ovary and capsule 2 to 5 



-celled; herbs Campaxi i.a< eae, p. 399. 



Leaves opposite or whorled. 



Stamens 1 to 3; flowers irregular; fruit 1-celled, 1-seeded; herbs 



Valebianaceae, p. 397. 



Stamens 4 or 5, rarely 2. 



Ovary 1-celled; flowers in involucrate heads or short spikes; fruit an 

 achene; herbs Dipsaceae, p. 398. 



