522 LABIATAE 
spikes. Calyx bell-shaped or tubular with 5 equal or nearly equal teeth. 
Corolla tube short, nearly or quite included in the calyx, the border spread- 
ing, of 4 nearly or quite equal lobes or the upper lobe broadest. Stamens 
4, all,equal or nearly so and all fertile. Ovary 4-parted. 
Flower spikes narrow, leafless, the flowers densely crowded; leaves without leaf- 
stalks. 
Plants not hairy. 
Spikes long, narrow, interrupted below . . . . . . M. spicata 
Spikes thick, mostly dense. 
Leaves lance-shaped be ee ee. we hey lng eer 
Leaves broad, egg-shaped . . . . . . . '. . WM. cttrata 
Plants more or less hairy. 
Spikes slender, dense or interrupted. 
eaves» lance Shaped ren arein areal meen she tener) Naraae M. longifolia 
Leaves broad, elliptic or egg-shaped . . . . M. rotundifolia 
Spikes not slender, dense. 
Leaves without leaf-stems . . . . . . M. alopecuroides 
Leaves with leaf-stems, some of which are quite short. 
Leaves with.simple teeth at margin . . . M. aquatica 
Leaves deeply incised . . . . . . . « M. crispa 
Flowers not in spikes, but in axillary whorls. 
Leaf margins with rounded teeth . . . +. - -. - - © « MM. arvensis 
Leaf margins with sharp teeth. 
Lower leaves egg-shaped, sharp pointed at apex, more or less 
rounded’ at base. 0 a: fe 6 je at wpe) pe os, eerie 
Leaves narrow, tapering at both ends. 
Calyx hairy all over . . . . = « « « « MM. ‘canadenss 
Galyx “hairy at border . « « = = o. + » « « | Me Ugentlss 
1. M. spicata, L. (Fig. 2, pl. 130.) Spearmint. Plant nearly or 
quite smooth; leaves oblong or nearly egg-shaped, coarsely toothed, with- 
out leaf-stems or with very short ones. Flowers in long slender spikes, 
tapering at end, interrupted, the central one much the longest. Flowers 
pale purple. Wet places, throughout our range. July-Sept. 
2. M. piperita, L.- (Fig. 1, pl. 130.) Prprrermint. Plant smooth 
or with a few hairs; branching, pungent to taste, 1 to 3 ft. high; leaves 
oblong-lance-shaped or lance-shaped, coarsely toothed and tapering at each 
end. Flowers in terminal spikes of many closely related dense whorls, the 
ends of which are blunt. Wet places, throughout our range. July-Sept. 
3. M. citrata, Ehrh. (Fig. 3, pl. 130.) BrercaMor Mint. Stem 1 to 
2 ft. long, nearly erect or decumbent; whole plant smooth. Leaves egg- 
shaped, rounded at base, the lower rather blunt, upper sharp pointed at 
apex, on rather long leaf-stems, larger leaf blades 2 in. long, nearly as 
wide, Flowers in dense terminal whorls and also in the upper axils. Wet 
soil. Not common. July-Sept. 
4. M. longifolia, Huds. (Fig. 7, pl. 130.) Horsemint. This plant 
bears a strong resemblance to M. spicata (No. 1), but is eovered with 
hairs, while the latter is smooth, Found in southern part of our region. 
July-Oct. 
5. M. rotundifolia, Huds. (Fig. 12, pl. 130.) Rounp-LEAveD MINT. 
Plant covered with long hairs; stem 1} to 24 ft. high; leaves round-egg- 
shaped or broad elliptic, without leaf-stalks, somewhat clasping the stem 
at base; upper surface dark green, lower whitish-silky. Borders with 
rounded teeth; flowers in terminal slender interrupted spikes; corolla 
slightly downy. Waste places in all of our area. July-Sept. 
6. M. alopecuroides, Hull. (Fig. 9, pl. 130.) Woorty Mint. Plant 
densely hairy, stem 14 to 3 ft. high. Leaves with sharp teeth at the mar- 
