ACANTHACEJE. (ACANTHUS FAMILY.) 297 



placenta. Flowers much bracted. Calyx 5-cleft. Style thread-form : 

 stigma simple or 2-cleft. Pod loculicidal, usually flattened contrary to the 

 valves and partition. Cotyledons broad and flat. Mucilaginous and 

 slightly bitter, not noxious. A large family in the tropics, represented in 

 the Northern States only by two genera. 



I 



1. DlANTHlSRA, Gronov. WATER- WILLOW. 



Calyx 5-parted. Corolla deeply 2-lipped ; the upper lip erect, notched ; the 

 lower spreading, 3-parted. Stamens 2 : anthers 2-celled, the cells placed one 

 lower down than the other. Pod obovate, flattened, contracted at the base into 

 a short stalk, 4-seeded. Perennial herbs, growing in water, with narrow and 

 entire leaves, and purplish flowers in axillary peduncled spikes or heads. (Name 

 from Si's, double, and dvdrjpd, antJier ; the separated cells giving the appearance 

 of two anthers on each filament.) 



1. I>. Americana., L. Leaves linear-lanceolate, elongated ; spikes ob- 

 long, dense, long-peduncled. (Justicia pedunculosa, Michx.) Borders of 

 streams and ponds, N. W. Vermont to Wisconsin, Virginia, and southward. 

 July -Sept, 



2. DIPTERACANTHUS, Nees. ( RUELLI A partly, L.) 



Calyx deeply 5-cleft. Corolla funnel-form, the spreading ample limb almost 

 equally and regularly 5-cleft. Stamens 4, included, didynamous : cells of the 

 somewhat arrow-shaped anthers parallel and nearly equal. Pod somewhat flat- 

 tened, and stalked at the base, 8 - 12-seeded. Seeds with a mucilaginous coat- 

 ing. Perennial herbs, not aquatic, with ovate or elliptical nearly entire leaves, 

 and large and showy blue or purple flowers, solitary, few, or clustered in the axils, 

 with a pair of leafy bracts (whence the name, from StWepos, two-winged, and 

 amavBos, the Acanthus}. 



1. D. CilidsilS, Nees. Hirsute with soft whitish hairs (l-3high); 

 leaves nearly sessile, oval or ovate-oblong (li'-2' long) ; flowers 1-3 and almost 

 sessile in the axils ; tube of the corolla (!'- 1' long) fully twice the length of the 

 setaceous calyx-lobes; the throat short. (Ruellia ciliosa, Pursh. E. hybridus, 

 Pursh., is only a Southern variety of this.) Dry soil, Michigan to Illinois, and 

 southward. June -Sept. 



2. 1>. StrepeilS, Nees. Glabrous or sparingly pubescent (l-4high); 

 leaves narrowed at the base into a petiole, ovate, obovate, or mostly oblong (2^' - 5' 

 long) ; tube of the corolla (about 1' long) little longer than the dilated portion, 

 slightly exceeding the lanceolate or linear calyx-lobes. Flowers 1 - 5 in each axil, 

 rarely on a slender peduncle, usually almost sessile ; sometimes many and closely 

 crowded, and mostly fruiting in the bud, the corolla small and not expanding 

 (when it is D. micranthus, Engelm. $ Gr.). Kich soil, Pennsylvania to Wis- 

 consin, and southward. July - Sept. 



DiCLfj'TERA BRAcmATA, Spreng. (Justicia brachiata, Pursh), probably 

 grows in the southern part of Virginia. 



