Along roadsides, in old fields, wet seepage areas, thickets and waste places 

 in cen. and w. Tex., N. M. (Dona Ana and Otero cos.) and Ariz. (Cochise Co.), 

 May-Sept.; a nat. of Eur. that has become naturalized in various parts of N.A. 



3. Mentha spicata L. Spearmint. Fig. 678. 



Perennial with stolons, glabrous or sparingly pubescent at the nodes: stems 

 usually branched, to 12 dm. high, often purplish; leaves sessile or short-petioled, 

 oblong-lanceolate to ovate-lanceolate, acute to acuminate at apex, obtuse to some- 

 what rounded to subcordate -at base, unequally sharply serrate, the larger leaves 

 3-6 cm. long; flower whorls in slender terminal leafless spikes often 6-8 cm. long 

 in fruit; bracts subulate-lanceolate, equaling or surpassing the calyx, green, 

 glabrous or ciliate; calyx teeth subulate, about equaling the tube, ciliate on the 

 margins, the inflorescence otherwise glabrous; corolla pale-lavender. 



In moist fields and wet meadows, seepage bank of streams and about springs, 

 open marshes and about ponds and along ditches, mostly near settlements, in cen. 

 and w. Tex., Okla. (Murray Co.), N.M. (Dona Ana, Guadalupe and Santa Fe 

 COS.) and Ariz. (Mohave, Yavapai, Santa Cruz. Pima and Gila cos.), June-Oct.; 

 a nat. of Eur. that has become naturalized in much of N.A. 



4. Mentha piperita L. Peppermint. Fig. 678. 



Perennial with underground sometimes leafy-bracted stolons; stems erect or 

 somewhat decumbent, branched, to about 8 dm. high, often purplish; leaves 

 petioled, lanceolate to ovate-lanceolate, acute, sharply serrate, dark-green and 

 firm, glabrous or sparsely pubescent on the veins beneath; whorls of flowers in 

 terminal dense or interrupted spikes, to 12 cm. long in fruit; bracts narrowly 

 lanceolate, acuminate, not surpassing the flowers; pedicels elongate; calyx tube 

 glabrous, the teeth about equaling or shorter than the tube and hirsute (sometimes 

 sparingly so), ciliate; corolla glabrous, rose-purple to white. 



In wet places about ponds, lakes and along streams, sloughs and ditches, wet 

 meadows and spring branches, mostly in w.-cen. Tex. and Okla. (Adair and 

 Cherokee cos.), June-Oct.; a nat. of Eur. that has become naturalized in much of 

 N.A. 



15. Pycnanthemum Michx. Mountain-mint. Basil 



Perennial erect herbs with a pungent mintlike flavor, corymbosely branched 

 above, the floral leaves often whitened; the many-flowered whorls dense, crowded 

 with bracts and usually forming terminal heads or close cymes; calyx about 13- 

 nerved, naked in the throat; corolla short, whitish or purplish, more or less 

 2-lipped, the lips mostly dotted with purple, the upper lip straight, nearly flat, 

 entire or slightly notched, the lower lip 3-cleft with its lobes all ovate to oblong 

 and obtuse; stamens exserted or included in different flowers; lower pair of 

 stamens rather longer than the upper; anther cells parallel. 



About 21 species, mostly in eastern United States. 



1. Leaves linear, entire, rarely more than 4 mm. wide 1. P. tenuifolium. 



1. Leaves ovate to linear-lanceolate, subentire to remotely toothed, usually more 



than 5 mm. wide (2) 



2(1). Leaves typically linear-lanceolate, subsessile or with petioles less than 3 

 mm. long; flowers in tight globose heads 2. P. virginianum. 



2. Leaves typically ovate-lanceolate, with petioles 4-12 mm. long; flo^.'ers in 



irregular corymbs to form glomerules 3. P. albescens. 



1. Pycnanthemum tenuifolium Schrad. Fig. 670. 



Plant to about 1 m. high, glabrous, forming dense colonies by horizontal roots, 

 usually bearing abundant sterile simple or forking axillary branches; leaves sessile, 

 linear, to about 6 cm. long and 5.5 mm. wide, tapering to apex, firm and some- 



1446 



