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* Corolla imbricated in bud; upper lip exterior: seeds small and globular. 
1. Elytraria. Bracts of the solitary or clustered spikes and the similar scales of 
the scape imbricated, glumaceous, 
* * Corolla convolute in bud, either bilabiate or nearly regular: seeds flat: stamens 
didynamous, the long and short filament on each side contiguous or united at 
base by a membrane; anthers 2-celled, the cells equal and parallel. 
+ Corolla deeply bilabiate: pod terete and 2-celled to the very base, 
2. Hygrophila. Corolla narrow: anthers oblong, pointless: flowers sessile in the 
axils, 
+ + Corolla only moderately bilabiate if at all: pod with base more or less contracted 
into a solid short stipe. 
3. Colophanes. Calyx-lobes elongated setaceous or aristiform: anthers mucro- 
nate or aristate at base: ovules 2 in each cell, 
4. Ruellia. Calyx-lobes linear or lanceolate: anthers pointless: ovules 3 to 10 in 
each cell. 
* * * Corolla imbricated in bud; posterior lobes or lip interior: ovules 2 in each cell: 
seeds and pod of * * 
+ Stamens 4, in the throat of the corolla; anthers 1-celled. 
5. Stenandrium. Lobesof the salverform corolla all equally spreading: low herbs. 
++ Stamens 2 and no rudiments; anthers 2-celled: pod with a conspicuous stipe-like 
solid base. 
++ Placent# not separating from the valves of the pod. 
= Anther-cells equal, parallel and contiguous, pointless: limb of corolla somewhat 
equally 4-parted: shrubby plants. 
6. Carlowrightia. Corolla with narrow tube shorter than the lobes, almost rotate, 
purple. 
7. Anisacanthus. Corolla with elongated tube, red, 
— = Anther-cells unequal or unequally inserted, one lower than the other or oblique. 
a. Lower anther-cell spurred or mucronate at base, 
8. Siphonoglossa. Corolla with long-linear or filiform tube and short limb: an- 
ther-cells contiguous and parallel, but one higher, 
9. Justicia. Corolla with short tube: anther-cells oblique and disjoined. 
b. Anthers pointless, or both cells rarely mucronulate at base. 
10. Dianthera. Corolla bilabiate: anther-cells not parallel, moderately or con. 
spicuously disjoined on a dilated connective. 
11. Gatesia. Corolla with slender tube and almost equally 4-lobed spreading limb: 
anther-cells contiguous and similar, but one a little lower and oblique. 
+++ Placente at length separating and diverging or incurving; corolla with narrow 
tube. 
12. Tetramerium. Flowers solitary (rarely 2 or 3), covered by a large and herba- 
ceous primary bract, and subtended by 2 small and narrow bractlets: spikes strobila- 
ceous. 
13. Dicliptera. Flowers not covered by primary bracts, but involucrate (either 
singly or in a fascicle) by 2 opposed and nearly equal or 4 less dilated and unequal 
herbaceous bractlets: inflorescence various, not strobilaceous-spicate, 
1. BLYTRARIA Michx. 
Low perennial herbs, with leaves crowded at base of a naked scape 
or at summit of a short naked stem, small flowers solitary and sessile 
under the bracts (these and the scales of the scapes rigid-chartaceous 
