ACANTHACEAE 1081 



39. SCH"WALBEA L. 



Perennial caulescent herbs, finely pubescent and glandular. Leaves alternate : blades 

 entire, 5-nerved, sessile. Flowers in terminal bracted racemes. Calyx of 5 well-united 

 sepals: tube 10-12-ribbed, oblique: lobes shorter tlian the tube. Corolla yellowish 

 purple, very irregular: upper lip arched, entire; lower lip shorter, 3-lobed, 2-plaited. 

 Stamens 4, didynamous, ascending under the upper lip of the corolla : anthers, and the sacs, 

 alike. Capsule narrow, loculicidal. Seeds numerous, with a loose reticulated testa. 



1. Schwalbea Americana L. Stems 3-8 dm. tall, simple or sparingly branched. 

 Leaf-blades oblong, elliptic or ovate-elliptic, 1.5-3.5 cm. long, acute, entire : (lowers short- 

 pedicelled : calyx thinly lanuginous, 1.5-2 cm. long ; upper and lateral lobes lanceolate, 

 the upper i as long as the lateral ; lower lobe oblong, with a V-shaped sinus at the apex : 

 corolla 3-3.5 cm. long, pubescent without ; tube surpassing the calyx, longer than the lips : 

 capsules oblong, 10-12 mm. long. 



In swamps or low grounds, Massachusetts to Florida and Louisiana. Spring and summer. 



Family 14. ACANTHACEAE J. St. Hil. Acanthus Family. 



Annual or perennial herbs, or shrubby plants pervaded by bitter, acrid or 

 often emollient properties, otherwise of little economic value. Stems enlarged 

 at the jointed nodes. Leaves alternate, opposite or rarely whorled, without 

 stipules : blades simple. FloM'ers perfect, irregular, sometimes solitary, often 

 subtended by conspicuous bracts. Calyx of 5 nearly distinct or variously united 

 sepals, sometimes subtended by bractlets. Corolla of 5 partially united petals, 

 2-lipped or sometimes almost regularly 5-lobed ; lobes convolute or contorted. 

 Androecium of four didynamous, or two ecpial stamens, the other pair abortive 

 or obsolete. Filaments filiform oi- subulate. Anthers with 2 equal or unequal 

 sacs. Gynoecium 2-carpellary. Ovary free, 2-celled with the placentae in the 

 axis. Styles terminal, united. Stigmas entire or 2. Ovules often few, com- 

 monly 2 in each cavity, sessile, amphiti'opous or campylotropous. Fruit a mem- 

 branous, leathery or cartilaginous capsule, typically with 2 cavities, opening 

 loculicidally and"^ elastically. Seeds usually flattened, with a leathery, fibrous 

 or loose, often tuberculate, sometimes pilose, testa. Embryo curved or rarely 

 straight, with large cotyledons. 



Leaves normal only at the base of the stem, those on the stem reduced to firm sheathing imbricated 



scales and passing into the inflorescence. 1. Tubiflora. 



Leaves normal on the stem. 

 Corolla convolute in the bud. 



Corolla conspicuously '2-lipped : capsule terete, not constricted at the base. 2. Hygrophila. 

 Corolla barely if at all i-lipped : capsule constricted into a stipe-like base. 

 Calyx-lobes bristle-like : anther-sacs awned or pointed at the base : ovules 



■ 2 in each cavity. 3. Calophanes. 



Calyx-lobes linear "or lanceolate : anther-sacs pointless : ovules 3-10 in 



each cavity. 4- Ruellia. 



Corolla imbricated in the bud. 



Stamens 4 : anthers 1-celled. 5. Stenandrium. 



Stamens 2 : anthers 2-celled. 



Placentae separating from the valves of the capsule. 



Flowers and their subtending bractlets covered by a large bract. G. Tetramerium. 



Flowers and their subtending bractlets not covered by a large bract. 7. Diapedium. 



Placentae persistently attached to the valves of the capsule. 



Anther-sacs equal," contiguous, parallel. 8. Amsacanthus. 



Anther-sacs unequal or unequally inserted, one lower than the other. 

 Lower anther-sac with a spurred or mucronate base. 



Corolla-tube elongated, slenderor filiform : anther-sacs unequally 



inserted, one lower than the other. 9. Siphonoglossa. 



Corolla-tube very short : anther-sacs separated, oblique. 10. Justicia. 



Both anther-sacs rounded, or rarely both mucronate at the base. 

 Corolla with 4 nearly equal lobes: anther-sacs contiguous, un- 

 equally inserted. 11. Yeatesia. 

 Corolla manifestly 2-lipped : anther-sacs separated on a dilated 

 connective. 

 Flowers on axillary peduncles : anther-sacs wholly separated, 



very oblique. " 12. Dianthera. 



Flowers "solitary in the axils of the leaves or in terminal bracted 



spikes: anther-sacs approximate, slightly oblique. 13. Croftia. 



1. TUBIFLORA J. F. Gmel. 

 Perennial caulescent herbs, with glabrous foliage. Stems sometimes scape-like. 

 Leaves alternate or nearly opposite, basal or crowded at the ends of the branches : blades 



