ACANTHACE.E. (ACANTHUS FAMILY.) 363 



11. ECHINOSPERMUM, Swartz. STICKSEED. 



Calyx, corolla, etc. of the preceding. Nutlets fixed to the side of the cen- 

 tral column, the back or margins only armed with barbed bristles. 



1. E. Virginicum, Lehm. Hairy; stem erect, rather slender, widely 

 branched ; leaves lanceolate-oblong, acute ; the lowest tapering into a petiole ; 

 racemes numerous, slender, villous, bracted; pedicels short, recurved in fruit; 

 corolla small, about as long as the calyx, white or pale blue. Dry woods in 

 the upper districts. June - July. Stem 2 - 3 high. 



2. E. Lappula, L. Stem erect, branched above, l-2 high, hirsute ; 

 leaves lanceolate; racemes bracted; pedicels of the (blue) flowers erect; 

 margins of the nutlets bristly. Waste ground, Tennessee. Introduced. 



ORDER 100. ACANTHACE^. (ACANTHUS FAMILY.) 



Chiefly herbs, with opposite (rarely alternate or clustered) undivided 

 exstipulate leaves, and bracted, often showy flowers. Calyx 5-parted. 

 Corolla more or less bilabiate, 5-lobed, twisted in the bud. Fertile 

 stamens 2 or 4, inserted on the tube of the corolla : anthers 2-celled. 

 Ovary free. Style single : stigma entire or 2-lobed. Capsule loculi- 

 cidally 2-valved, 2-celled, 4 -several-seeded, opening elastically. Seeds 

 anatropous, flat, rounded, without albumen (except Elytraria), mostly 

 supported by curved appendages of the placenta?. Radicle inferior. 

 Stems commonly swollen between the joints. 



Synopsis. 



* Capsule obloug, bearing the seeds at the base. Appendages of the placentae none. 



1. ELYTRARIA. Spike borne on a closely-bracted scape. Leaves radical. 



2. HYGROPHILA. Stem leafy. Flowers axillary. Corolla 2-lipped. 



* * Capsule club-shaped. Seeds supported by an appendage. 

 H- Corolla convolute in the bud. 



3. RUELLIA. Corolla regular. Anther cells pointless. Capsule several-seeded. 



4. CALOPHANES. Corolla slightly 2-lipped. Anther cells pointed at the base. Capsule 



2-4-seeded. 



i- (- Corolla imbricate in the bud. 



++ Stamens 4. 



5 STENANDRITJM. Corolla regular. Anthers 1-celled. Stem scape-like. 



++ -M- Stamens 2. 



6. GATESIA. Corolla regular. Anther cells oblong, one lower than the other. 



7. DIANTHERA. Corolla bilabiate. Stamens 2. Cells of the anthers placed one lower 



than the other. Flowers in long-peduiicled axillary spikes. 



8. DICLIPTERA. Corolla bilabiate, resupinate. Stamens 2. Cells of the anthers placed 



one behind the other. Flowers in leafy-bracted heads or clusters. 



1. ELYTRARIA, Vahl. 



Calyx 4 - 5-parted, the lateral lobes narrower. Corolla salver-shaped or bi- 

 labiate, 5-lobed. Fertile stamens 2, the 2 anterior sterile : anther cells parallel. 

 Stigma 2-cleft. Capsule sessile, about 8-seeded ; the seeds fixed near the base of 



