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* Spikes narrow and leafless, densely crowded : leaves sessile or nearly 80. 
1. M. rotundifolia L. Soft-hairy or downy: leaves broadly elliptical to round- 
ovate and somewhat heart-shaped, rugose, crenate-toothed: spikes slender, not 
canescent.—Maine to Texas. 
2, M. viridis L. Nearly smooth: leaves oblong or ovate-lanceolate, unequally 
serrate: bracts linear-lanceolate and subulate, conspicuous.—Wet ground, reported 
from Gillespie County (Jermy). “Spearmint.” 
** Flowers pedicellate, less crowded, in interrupted leafless spikes, or some in the upper 
axils: leaves petioled. 
3. M. piperita L. Glabrous, very pungent-tastéd: leaves ovate-oblong to oblong- 
lanceolate, acute, sharply serrate: spikes narrow, loose.—Along brooks, escaped 
everywhere. ‘‘Peppermint.” 
7. LYCOPUS Tourn. (WATER HOREHOUND.) 
Perennial low glabrous or puberulent herbs, with sharply toothed or 
pinnatifid leaves, floral ones similar and much longer than the dense 
axillary whorls of small mostly white flowers, bell-shaped 4 or 5-toothed 
calyx naked in the throat, bell-shaped nearly equally 4-lobed corolla 
scarcely longer than the calyx, and 2 distant stamens (the upper pair 
either sterile rudiments or wanting). 
1. L. sinuatus Ell. Stem erect, 3 to 9 dm. high, acutely 4-angled: leaves oblong 
or lanceolate, acuminate, irregularly incised or laciniate-pinnatifid, or some of the 
upper merely sinuate, tapering to a slender petiole: calyx-teeth short-cuspidate: 
sterile filaments slender, conspicuous, with globular or spatulate tips. (L. Europeus, 
var. sinuatus Gray.)—Extending from the Atlantic region into Texas. 
8. PYCNANTHEMUM Michx. (Mountain Mint. BasIt.) 
Perennial upright herbs, with a pungent mint-like flavor, floral leaves 
often whitened, whitish or purplish flowers (lips mostly dotted with 
purple) in many-flowered dense whorls crowded with bracts and usually 
forming terminal heads on close cymes, ovate-oblong or tubular equally 
5-toothed or 2-lipped calyx naked in the throat, short more or less 
2-lipped corolla (upper lip straight, nearly flat, entire or slightly notched; 
lower 3-cleft), 4 distant stamens with outer pair rather longer, and par. 
allel anther-cells. 
1. P. linifolium Pursh. Glabrous up to the canescent inflorescence, 6 dm. high: 
leaves linear, nearly sessile, entire, mostly glabrous, very numerous: capitate glom.- 
erules small and numerous, densely cymose, imbricated with many short appressed 
rigid bracts, these and the lance-awl-shaped calyx-teeth pungently pointed: calyx 
equally 5-toothed.—Dry ground, extending from the Atlantic region to Texas. 
2. P. albescens Torr. & Gray. Stems slender, puberulent: leaves oblong or 
ovate-lanceolate, obscurely serrate, small, canescent beneath and the uppermost on 
both sides with a minute close pubescence, as also are the short and beardless calyx 
and bracts: calyx 2-lipped, with short triangular-ovate obtuse teeth.—Extending 
from the Gulf States into Texas. 
9. MICROMERIA Benth. 
Diffusely spreading or creeping perennial herbs, with rounded and 
petioled veiny thin leaves, 1 to 3 slender-pediceled purplish axillary 
