276 



lip erect, nearly flat, emarginate ; lower spreading, almost 

 equally 3-cleft. Stamens 4, the lower ones longer. 



O. vulgare Linn. : erect, villous ; leaves broad-ovate, petiolate, obtuse, 

 nearly entire ; spikes roundish, panicled, clustered, smooth ; bracts ovate, 

 longer than the calyx. 



Rocky fields. N. S. July Sept. *2|.. Stem 812 inches high, hairy. 

 Flowers pale-purple, in numerous small spikes which are crowded together so 

 as to form a terminal head. Introduced ? Common Marjoram. 



10. COLLINSONIA. Linn. Horse Balm. 

 (In ho7ior of Peter Collinson, of London, a patron of botany.) 



Calyx ovoid, about 10-nerved, 2-lipped ; upper lip 3-toothed; 

 lower bifid. Corolla subcampanulate, somewhat 2-lipped ; the 

 lower lobe longer than the rest, toothed or fimbriate ; throat 

 dilated. Stamens mostly 2, much exserted, diverging. 



C. Canadensis Linn. : stem smoothish ; leaves broad-ovate, acuminate, 

 coarsely serrate, thin and smoothish; flowers diandrous, in a loose terminal 

 panicle. 



Woods. Can. to Car. July, Aug. Ij.. Stem 2 3 feet high, somewhat 

 branched, 4-angled. Leaves large, cordate or obtusely cuneate at base. Flowers 

 large, greenish-yellow. Sold by the Shakers under the name of Stone-root. 



Common Horse-balm. 



11. CUN1LA. Linn. Dittany. 

 (A name borrowed from the ancient Roman naturalists.) 

 Calyx ovoid-tubular, about 13-nerved, 5-toothed; throat 

 densely villous. Corolla 2-lipped ; upper lip flat and emargi- 

 nate; lower 3-lobed. Stamens 2, erect, exserted, distant. Style 

 bifid at the summit. 



C. Mariana Linn. : herbaceous : leaves subsessile, ovate, somewhat cor- 

 date at base, serrate; cymes pedunculate, loosely corymbose. 



Dry hills and rocks. Can. to Car. W. to Arkansas. July Aug. 7J.. Stem 

 8 12 inches high, 4-angled, much branched, purple. Leaves sessile or on very 

 short petioles, smoothish. Flowers pale red. Common Dittany. 



IV. MELISSINEJE. Calyx mostly 13-nerved, 2-lipped. Corolla 2- 

 lipped; the divisions Jlattish, or the upper lip rarely galeale. Stamens 

 4, or sometimes 2, ascending. 



12. HEDEOMA. Pers. Pennyroyal. 

 (From the Greek tibia, sweet, and 0^17, odor ; in allusion to its fragrance.) 



Calyx ovoid-tubular, gibbous on the under side at the base, 

 2-lipped; upper lip 3-toothed or 3-cleft; lower 2-cleft. Corolla 

 2-lipped ; upper lip erect, flat ; lower spreading, 3-cleft. Stamens 

 2 sterile, rudimentary or wanting ; 2 fertile and ascending. 



