322 ACANTHACEiE. 



and mainly tropical or subtropical order, one strongly marked tribe of which is 

 represented in ornamental cultivation by Thimbergia, another sparingly so by 

 the Acanthus of the Old World ; the others have several North American repre- 

 sentatives. 



Tribe I. NELSONIEiE. Corolla imbricated in the bud ; upper lip exterior. Seeds 

 small and globular, attached by a small ventral papilliform funicle, without reti- 

 nacula, not nmoilaginous when wetted: embryo in a thin layer of albumen ! (In 

 char, nearest to Scrophulariacem, but capsule and habit of Acanlhacece.') 



1. ELYTRARIA. Calyx 4-parted; lower division sometimes 2-toothed. Corolla with 

 cylindraceous tube, funnelform throat, and 5-lobed or soniewliat bilabiate limb. Stamens 

 2 : filaments very short, inserted low in the throat : anther-cells equal and parallel. 

 Stigma 2-lobed. Ovules 6 to 10 in each cell. Capsule oblong, thinner and contracted at 

 base, acute at tip. Seeds globular. Bracts of the solitary or fasciculate-clustered spikes 

 and the similar scales of the scape imbricated, glumaceous. 



Tribe II. EuelliejE. Corolla convolute (sinistrorsely) in the bud, either bilabiate 

 or nearly regular. Seeds flat, attached by the edge to retinacula. (Stamens in 

 ours didynamous, the long and the short filament on each side contiguous or united 

 at base by a membrane ; the anthers 2-oelled, and the cells equal and parallel : 

 style with linear or subulate stigmatose apex, the posterior lobe wanting or reduced 

 to a minute tooth, or rarely 2 equal narrow stigmas.) 



* Corolla deeply bilabiate : capsule terete and 2-celled to the very base. 



S. HYGROPHILA. Calyx deeply and almost equally 5-cleft or parted. Corolla narrow ; 

 lips erect at base and above (at least tlie lower) spreading, 2- and 3-lobed. Anthers oblong, 

 muticous. Capsule oblong-linear, several-seeded. Flowers sessile in the axils. 



# * Corolla not obviously or only moderately bilabiate, the 5 lobes broad and roundish, 

 spreading : capsule with the base more or less contracted into a solid short stipe. 



3. CALOPHANES. Calyx deeply 5-cleft or parted ; lobes elongated setaceous-acuminate 

 or aristitorm. Corolla funnelform, with ample limb, either somewhat manifestly bilabiate, 

 or with 5 equal broad and spreading lobes, the two posterior a little higher united. An- 

 thers mucronate, or at least mucronulate, or sometimes aristate at base. Ovules a single 

 pair in each cell. Capsule oblong-linear, 2-4-seeded. 



4. RUELLIA. Calyx deeply 5-cleft or parted; lobes mostly hnear or lanceolate. Corolla 

 with funnelform or campanulate throat on a narrow and sometimes elongated tube ; the 

 5 ovate or rounded lobes nearly similar and spreading, or the posterior ratlicr more 

 united. Anthers muticous, oblong-sagittate. Ovules 3 to 10 in each cell. Capsule oblong- 

 linear or clavate, several- (G-20-) seeded. 



Tribe III. JUSTICIE^. Corolla imbricated in the bud ; the posterior lobes or 

 lip interior. Seeds and capsule of the preceding tribe ; in the last two genera the 

 placentiferous half-portions separating below from the valve after dehiscence. 



# Stamens 4, in the throat of the corolla : filaments short : anthers one-celled, ovate-lan- 

 ceolate or oblong, muticous at base, their tips sometimes lightly cohering by a minute 

 beard: corolla witli 5 plane obovate lobes, the two posterior usually united a little 

 higher: stigma naked, truncate or obscurely funnelform : ovules 2 in each cell: calyx 

 5-sepalous or 5-parted into narrow nearly equal divisions. 



5. STENANDRIUM. Lobes of the salverform corolla all equally spreading. Low herbs. 



6. BERGINIA. Posterior lobes of the corolla nearly erect, forming an upper lip, the 

 3 otlicrs larger and widely spreading. Anterior pair of filaments bearded on the inner 

 side: anthers ovatc-laneeolate. Seeds (mostly 2) rugose. Fruticulose. 



# * Stamens 2 and no rudiments : anthers 2-eelled: ovules 2 in each cell; capsule usu- 

 ally more or less obcompressed, and with a conspicuous stipe-like solid base. 



H— Placentae not separating from the valves of the capsule. 

 ++ Anther-cells equal, parallel and contiguous, muticous : limb of corolla somewhat 

 equally 4-parted : shrubby plants: bracts and bractlets small and narrow or minute: 

 calyx small, 5-parted or 5-cIeft; the divisions narrow: stigma obscurely capitate or 

 emarginate: filaments filiform, inserted in the throat. 



7. CARLOWRIGHTIA. Corolla with narrow tube shorter than the lobes; throat not 

 dilated; limb 4-parted down to the tube; lobes entire, oblong, nearly similar, widely 



