396 



PHARMACEUTICAL BOTANY 



pentamerous, rarely tetramerous; sepals five, synsepalous, ribbed 

 and forming a tubular regular or irregular bilabiate (Scullcap, etc.) 

 calyx whose upper lip is bifid and lower trifid; corolla of five to four 

 gamopetalous petals, hypogynous, frequently two-lipped, the upper 

 lip bifid, the lower trifid; stamens four, didynamous, rarely one pair 

 alone fertile and the other pair reduced, in some cases almost or 



FIG. 231. Mentha piperita Flowering branch. (Sayre.) 



quite to disappearing point (Salvia and Monarda) ; pistil bicarpellate, 

 embryologically two-celled with two ovules in each cavity, becoming, 

 at time of flowering, four-celled with one ovule in each cavity. Style 

 embryologically terminal, but, upon opening of flower, deeply gyno- 

 basic, elongate, slender with two stigmatic surfaces. Fruit four 

 nutlets enclosing as many exalbuminous seeds. 



