370 
LXXIII. ACANTHACEiE 
stalks hardened, incurved. — A large Order, widely distributed, 
chiefly in tropical regions. — Named from the genus Acanthus 
which is lemarkable for its beautiful leaves. 
Perfect stamens 4. 
Corolla-limb spreading. 
Anther-bases bristle-tipped .... 2. 
Anther-bases blunt. 
Ovules 4-6 in each cell. Capsule linear. 
Seeds 6-8 ...... 4. 
Ovules 2 in each cell. Capsule oblong. 
Seeds 4 or fewer ..... 5. 
Corolla-limb 2-lipped. 
Flowers. in axillary, spinous whorls . ^ 1. 
Flowers in unarmed spikes .... 7. 
Perfect stamens 2. 
Corolla-limb spreading. 
Flowers deep blue. Calyx equally 5-lobed . 8. 
Flowers lilac or pink. Calyx unequally 4- 
parted 6. 
Corolla-limb 2-lipped. 
Flowers purple or pink. 
Corolla-tube straight. Lower anther-cell 
spurred .... 8. 
Corolla-tube twisted. Anther-cells not 
spurred 10. 
Flowers pale blue or white, sometimes 
dotted and streaked with pink. 
A creeping herb. Flowers ^ in. long, pale 
blue or white . . . . .1. 
An erect shrub. Flowers 1|- in. long, white, 
dotted and streaked with pink . . 9. 
Petalidium. 
JEchmanthera. 
Strobilanthes. 
Hygrophila spinosa. 
Lepidagathis. 
Dcedalacanthus. 
Barleriad 
Justicia. 
Dicliptera. 
Hygrophila polysperma .' 
Adhatoda. 
1. HYGROPHILA. From the Greek hygros, wet, moist, and 
phileo, to love ; referring to the habitat of the plants. — Most 
tropical and subtropical regions. 
Erect or procumbent herbs, growing in marshy places, 
unarmed or furnished with axillary spines. Leaves sessile, entire. 
Flowers nearly sessile, crowded in spikes or axillary whorls ; 
bracts lanceolate ; bracteoles linear. Calyx 5-lobed or 4-parted ; 
lobes or segments narrowly lanceolate. Corolla-tube dilated near 
the mouth ; limb 2-lipped, upper lip erect, concave, notched or 
2-lobed, lower spreading, 3-lobed. Stamens 4 or 2. Style-tip 
linear, recurved, the upper lobe reduced to a minute tooth ; ovules 
2-4 or many in each cell. Capsule linear-oblong ; seeds 4-8 or 
numerous. 
Procumbent, unarmed. Flowers in spikes. Calyx 5-lobed 1. H. polysperma. 
-Erect, spinous. Flowers in whorls. Calyx 4-parted . 2. H. spinosa. 
1 Barleria and Hygrophila polysperma have 2 very short imperfect stamens 
in addition to the 2 long perfect ones. 
