170 SUMMER FLOWERS. 



ft Stamens nearly equal. 

 % Corolla nearly equal. 



(222) Mentha — calyx equal, five-toothed ; corolla four-lobed, 



the tube very short. 



(223) Origanum — calyx witli five equal teeth ; corolla five-lobed 



obscurely two lipped ; flowers in four-sided spikes, with 

 imbricated bracts. 



(224) Thymus — calyx two-lipped ; corolla five-lobed, obscurely 



two-lipped ; flowers whorled, axillary, or spiked. 



ttt Two upper stamens shorter tlian the lower. 



X Corolla distinctly two-lipped^ the upper Up longer than 

 the stamens. 



§ Calyx regularly five-lohed. 



II Stamens shorter than the corolla tube. 



(225) Marrubium — calyx tubular, the teeth nearly equal ; upper 



lip of corolla straight, erect, cloven ; nuts flatly truncate 



nil Stamens longer than the corolla tuhe. 



(226) Galeopsis — calyx tubular, the teeth equal ; upper lip of 



corolla arched ; nuts rounded at the end. 



(227) Stachys — calyx tubular-bellshaped, the teeth equal ; upper 



lip of corolla concave; nuts obtuse and convex at the 

 end. 



(228) Leonurus — calyx tubular, the teeth nearly equal ; upper 



lip of corolla nearly flat ; nuts flatly truncate. 



(229) Ballota — calyx funnel-shaped, the teeth equal; upper lip 



of the corolla erect, concave ; nuts convex, and rounded 

 at the end. 



§§ Calyx obviously two-lipped. 



(230) Scutellaria — calyx ultimately closed and compressed, both 



lips entire, upper with a concave scale on its back ; corolla 

 two-lipped, the upper lip concave. 



(231) Prunella — calyx ultimately closed and compressed, the 



