Origanum. LABIATE, 65 



western counties. Probably introduced. June - October. This plant is aromatic and rather 

 ornamental. It yields an acrid essential oil that is sometimes employed for curing toothache. 

 Tlie leaves are used as a tea ; and also for dyeing woollen and linen of a brown and purple 

 color. 



8. COLLINSONIA. Linn. ; Benth Lab. p. 357. HORSE BALM. 



[ Named in honor of Peter Collinson of London, a distinguished patron of Botany.] 

 Caljrs ovate, 2-lipped ; the upper lip nearly plane, 3-toothed ; lower 2-toothed. Corolla 

 somewhat campanulale ; the throat large and open, somewhat 2-lipped ; the lower lobe 

 declined, longer than the others, and lacerately fimbriate or toothed. Stamens 2 or rarely 

 4, spreading, much exserted : anthers 2-celIed ; the cells divaricate. — Herbs of a heavy 

 odor, with large leaves, and flowers in panicles or sometimes simple racemes. 



1. CoLLiNSONiA Canadensis, Linn. Common Horse-halm. Knot-root. 



Stem nearly smooth ; leaves ovate, acuminate, coarsely serrate ; flowers numerous, in a 

 terminal loose panicle, diandrous. — Linn. sp. 1. p. 28 ; Michx. Jl. 1. p. 17 ; Pursh, fl. 1. 

 p. 20 ; Ell. sk. 1. p. 34 ; Torr. fl. 1. p.29; Bigel. jl. Bost. p. 10 ; Beck, hot. p. ^Tlb ; 

 Darlingt. jl. Cest. p. 349 ; Benth. Lab. p. 358. G. ovata, Pursh, I. c. fide Benth. ; Ell. 

 sk. I. c. 



Perennial. Stem 2-3 feet high, somewhat branching, obtusely 4-angled, often more or 

 less pubescent at the summit. Leaves opposite, 3-8 inches long and 3-4 broad, thin, 

 cordate or sometimes obtusely cuneate at the base ; the lower ones on long petioles ; upper- 

 most on short petioles, or sessile. Racemes of flowers disposed in a large panicle ; the 

 branches and pedicels opposite. Bracts shorter than the pedicels. Calyx smoothish ; teeth 

 of the upper lip shorter than those of the lower. Corolla greenish yellow, half an inch or 

 more in length ; the lower lip beautifully fringed. 



Woods, in rich soil ; common. July - August. The flowers have a strong odor of limes. 

 The root is sold by the Shakers under the name of Stone-root, and an infusion of it is reputed 

 to possess diuretic and tonic powers. 



9. CUNILA. Linn. ; Benth. Lab. p. 360. dittany. 



[An ancient Roman name, applied by Linnseus to this genus.] 



Calyx ovate-tubular, equally 5-toothed, villous in the throat. Corolla 2-lipped : upper lip 

 erect, flattish, often emarginate ; the lower spreading, 3-lobed ; the lobes nearly equal and 

 entire, or the middle one larger and emarginate. Stamens 2, erect, exserted, distant ; the 

 cells parallel, or at length divaricate. — Herbs or shrubby plants. Cymules loose, few- or 

 many-flowered, usually axillary, sometimes capitate or spiked. 

 [Flora — Vol. 2,] 9 



