1928 A TEXTBOOK OF THEORETICAL BOTANY 



The flowers (Fig. 1855) are hermaphrodite, zygomorphic and penta- 

 merous though certain parts are often suppressed in individual genera. 



A B 



Fig. 1855. — Floral diagrams of Labiatae. A, Lomiiim album. 

 B, Sahia officinalis. {After EichJer.) 



They may be either axillary or whorled. In some genera, e.g.. Thymus, 

 Nepeta (Fig. 1856) znd Prunella, separate female flowers occur in addition 

 to hermaphrodite ones, a condition known as gynodioecism which probably 

 promotes cross-pollination. 



ik^ 



Fig. 1856. — Nepeta musseni. 

 Inflorescence. 



Fig. 1857. — Laniium album. 

 Flower in longitudinal 

 section. Young stage before 

 the extrusion of the stigmas, 

 which are still covered by 

 the hood of the corolla. 



The calyx is persistent, gamosepalous, tubular or funnel-shaped, 



composed generally of five sepals. In certain genera it may be two-cleft. 



The corolla is usually zygomorphic and two-lipped (Fig. 1857), 



