CLASSIFICATION OF ANGIOSPERMS. 



369 



both being deeply bilabiate. Only the two anterior stamens are 

 fertile (bear anthers) ; the connective is transverse, the upper 

 end bearing a perfect pollen-sac and the lower, a somewhat 

 enlarged rudimentary pollen-sac, while the posterior pair of sta- 



FiG. 17s. Peppermint (Mentha piperita) showing the stolons (A), the opposite 

 petiolate leaves and the spikes with crowded flowers. 



mens are entirely rudimentary (Fig. 84, F). The nutlets are egg- 

 shaped, 3-angled, smooth and have an outer mucilaginous layer. 

 Hedeoma pulegioides (American pennyroyal) is an annual 

 herb (Fig. 271) with a slender, erect stem and numerous ascend- 

 ing branches. The leaves and flowering tops are official (p. 628). 



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