Verbenacecz - Verbena. 



357 



Didnthera Americana, Water Willow, is a pretty North 

 American aquatic perennial 1 to 2 feet 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. 



ORDER LXXXIIL VERBENACEJE. 



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. 

 Annual or perennial 

 herbs or undershrubs 

 with opposite or whorled 

 simple pinnatifid or lobed 

 leaves. Calyx ribbed, 

 irregularly 5-toothed. 

 Corolla salver-s h a p e d ; 

 tube often curved ; limb 

 regular, spreading, or 

 more or less bilabiate. 

 Stamens 4, included. 

 Fruit splitting into four 

 1 -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 leaves and elongating bracteolate 



Fig. 197. Verbena Aubletia. (} nat. size.) 



