Verbenacce—V erbena. 357 
Didnthera Americana, Water Willow, is a pretty North 
American aquatic perennial 1 to 2 fcet high with linear- 
lanceolate glabrous leaves and axillary long-stalked dense 
spikes of purplish bilabiate flowers. It is peculiar in having 
the anther-cells of the two stamens placed one below the other. 
Orver LXXXIII—VERBENACEZ. 
Shrubs or herbs with opposite or verticillate exstipulate 
leaves. Flowers corymbose, spicate or capitate, rarely solitary. 
Calyx tubular, persistent, inferior. Corolla deciduous, irregular, 
often 2-lipped. Stamens 4 and didynamous, or only 2. Style 
terminating the ovary. Fruit 2- or 4-celled, nucamentaceous 
or drupaceous; cells 1-seeded. There are between 40 and 
50 genera and about 600 species, common in the tropics, but 
rare in temperate regions. 
1. VERBENA. 
herbs or undershrubs 
with opposite or whorled 
simple pinnatifid or lobed 
leaves. Calyx ribbed, 
irregularly 5-toothed. 
Corolla salver-shaped; 
tube often curved; limb 
regular, spreading, or 
more or less bilabiate. 
Stamens 4, included. 
Fruit splitting into four 
l-seeded nutlets. The 
species are estimated at 
about 70, nearly all of 
which are American. 
We have, however, one 
common European spe- 
cies which extends to 
England, and is especi- 
ally abundant in the south. It is the V. officinalis, Vervain, 
a slender plant from 1 to 3 feet high with opposite oblong 
pinnatifid or tripartite jeaves and elongating bracteolate 
Fig. 197. Verbena Aubletia. (4 nat. size.) 
