LABIAT.E. (MINT FAMILY.) 375 



sterile, included or wanting- anther cells parallel. Style 2-cleft at the apex. 

 Nutlets 3-angled, truncate at the apex, narrowed at the base. Marsh or 

 aquatic mostly stolouiferous herbs. Leaves mostly toothed or pinnatifid. 

 Whorls dense, axillary. Flowers small, sessile, white. 



1. L. Virginicus, L. Stem smoothish ; leaves ovate-lanceolate, toothed- 

 serrate, acute or acuminate at each end ; calyx teeth 4, ovate, obtuse ; corolla 

 small, exserted ; sterile stamens minute. Ponds and ditches. Sept. Stem 

 l-2 high. Leaves l'-2' long. 



2. L. sinuatus, Ell. Stem 2 - 4 high, smooth, much branched ; leaves 

 piunatifid-toothed, ovate-oblong, tapering at each end; the upper ones nar- 

 rower ; calyx teeth 5, lanceolate-subulate, acute ; corolla twice as long as the 

 calyx ; sterile stamens minute or none. Ponds and wet grounds. August - 

 Sept. 



3. L. rubellus, Moench. Closely pubescent or tomentose; stem l-2 

 high, simple or branched, very leafy ; leaves ovate-lanceolate, acuminate at 

 each end, coarsely serrate; whorls dense; calyx teeth subulate, pubescent, 

 nearly as long as the corolla ; seeds pitted. Wet banks, mostly in the upper 

 districts. August -Sept. 



4. L. sessilifolius, Gray. Pubescent; stem simple or sparingly 

 branched ; leaves sessile, lanceolate or linear, toothed, serrate, or entire, resi- 

 nous-dotted ; calyx teeth subulate. Ponds and ditches in the lower districts. 

 August - Oct. Stem 2 - 4 high. Leaves 2' - 4' long. 



5. CUNILA, L. DITTANY. 



Calyx tubular, 10-nerved, equally 5-toothed, hairy in the throat. Corolla 

 2-lipped ; the upper lip notched or entire, the lower 3-cleft. Stamens 2, dis- 

 tant, exserted : anther cells parallel. Style 2-cleft at the apex. Nutlets 

 smooth. Perennial herbs. Flowers small, in corymbose or crowded whorls. 



1. C. Mariana, L. Smooth; stem slender, much branched ; leaves ovate, 

 serrate, acute, rounded or cordate at the base, subsessile ; cymes loose, axillary 

 and terminal, peduncled, mostly shorter than the leaves, corymbose; calyx 

 teeth lanceolate, acute. Dry soil along the mountains, Georgia, and north- 

 ward. July -Sept. Stem 1 high. Leaves 1' long. Flowers purple. 



6. PYCNANTHEMUM, Michx. HORSE-MINT. 



Calyx tubular, 13 nerved, naked in the throat, equally 5-toothed, or slightly 

 2-lipped. Corolla 2-lipped ; the upper lip notched or entire, the lower 3-cleft. 

 Stamens 4, nearly equal, straight, spreading, commonly exserted .- anther cells 

 parallel. Style 2-cleft at the apex. Nutlets smooth. Perennial mostly pu- 

 bescent or hoary herbs, with erect branching stems. Floral leaves often white, 

 tomentose. Cymes mostly terminal, bracted. Corolla small, white or pur- 

 plish. Plants aromatic and pungent. 

 * Calyx more or less 2-lipped, the subulate teeth often bearded with weak jointed 



hairs: cymes mostly terminal, widely spreading in fruit: bracts longer than 



the flowers : leaves pubescent, the uppermost whitened. 



1. P. incanum, Michx. Stem densely pubescent and hoary; leaves 

 ovate or oblong-ovate, acute, sharply serrate, short-petioled, hoary-tomentose 



