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2. Mentha L. Munt. 
Calyx 5-dentate. Tube of corolla included. 
limb exserted, 4-lobed; upper lobe the larg- 
est. Stamens 4, scarcely didynamous, erect, 
distant. Anthers 2-celled. Cells parallel.—2¢. 
1. M. viaipis L. Inflorescence terminal; 
dense glomerules, crowded around narrow 
spikes; spikes leafless; leaves almost sessile. 
Irrigated grounds. Summer. Autumn. Es- 
caped from cultivation. Native of Europe. 
(Spearmint. ) ‘ 
2. M. preerita L. Inflorescence terminal; 
glomerules on uninterrupted narrow spikes; 
spikes leafless; leaves distinctly petioled; flow- 
ers pale.—Irrigated grounds. Summer. Au- 
tumn. Escaped from cultivation. Native of 
Europe. (Peppermint.) 
3. M. Canavensis L. Inflorescence axil- 
lary; uppermost axils of leaves without flow- 
ers.—Wet places. Native species. Summer. 
3; Lycopus Tourn. Water HorEHouND. 
Diandrous. Posterior pair of stamens 0 or 
sterile. Otherwise as Mentha.—2f. 
1. IL. nucwus Turez. Flowers pale—Marin 
County. Aquatic. Summer. 
4, Pycnanthemum Benth. Moonratn Mrvr. 
Corolla tube as long as the calyx, limb 2- 
labiate, upper lip nearly entire. Lower lip 
