GENUS 36. 



MINT FAMILY. 



12. Mentha gentilis L. Creeping or Downy 

 Whorled Mint. Spearmint. Fig. 3691. 



Mentha gentilis L. Sp. PI. 577. 1753. 

 Mentha sativa L. Sp. PI. Ed. 2, 805. 1763. 



Perennial by suckers ; stem rather stout, ascend- 

 ing or erect, branched, glabrous or puberulent 

 with short reflexed hairs, i-2 high. Leaves 

 ovate or oval, short-petioled, sparingly pubescent 

 with scattered hairs on both surfaces, often blotch- 

 ed, pinnately veined, acute at both ends, sharply 

 serrate, the larger i-2 r long, the upper some- 

 times much smaller than the lower; wKorls of 

 flowers all axillary; pedicels glabrous ; calyx cam- 

 panulate, glabrous below, its teeth subulate, ciliate, 

 one-half as long as the tube; corolla glabrous. 



In waste places and along streams, Nova Scotia to 

 northern New York, Iowa, North Carolina and Ten- 

 nessee. Naturalized from Europe. Aug.-Oct. 



37. COLLINSONIA L: Sp. PI. 28. 

 1753- 



Tall perennial aromatic herbs, with large membranous petioled leaves, and terminal 

 loosely panicled racemes of small, yellowish, mostly opposite flowers. Calyx campanulate, 

 short, io-nerved,2-lipped, declined in fruit, usually pubescent in the throat ; upper lip 3-toothed; 

 lower 2-cleft. Corolla much longer than the calyx, obliquely campanulate, 5-lobed, 4 of the 

 lobes nearly equal, the 5th pendent or declined, fimbriate or lacerate, much larger, appearing 

 like a lower lip. Anther-bearing stamens 2, not declined, much exserted, coiled before 

 antithesis; bases of the filaments connected by a woolly ring; anthers 2-celled, or the sacs 

 at length partially confluent. Ovary deeply 4-parted. Nutlets smooth, globose. [Named for 

 Peter Collinson, 1693-1768, an English botanist, and correspondent of Linnaeus.] 



Three species, natives of eastern North America, the following typical. 



i. Collinsonia canadensis L. 



Horse- or Ox-balm. 

 Fig. 3692. 



Citronella. Rich-weed. 



Collinsonia canadensis L. Sp. PI. 28. 1753. 



Stem stout, erect or ascending, branch- 

 ed, 2-5 high, glabrous, or glandular- 

 pubescent above. Leaves ovate or ovate- 

 oblong, acuminate at the apex, narrowed, 

 obtuse or sometimes cordate at the base, 

 the lower slender-petioled, 6'-io' long, the 

 upper nearly sessile, much smaller, all 

 coarsely dentate ; racemes numerous, in 

 terminal panicles sometimes i long; pedi- 

 cels ascending, 3"-6" long in fruit, subu- 

 late-bracteolate at the base ; flowers lemon- 

 scented ; calyx-teeth subulate, those of the 

 lower lip much longer than the upper; 

 corolla light yellow, 5"~7" long; anther- 

 bearing stamens 2, the upper pair rudi- 

 mentary ; fruiting calyx ribbed, 3"~4" long. 



In moist woods, Quebec and Ontario to 

 Wisconsin, south to Florida, Alabama and 

 Arkansas. Root large, thick, woody. Knob- 

 or horse-weed. Knob-grass or -root. Collin- 

 son's-flower. Rich leaf. Stone-root. July Oct. 



38. PERILLA Ard. ; L. Gen. PI. Ed. 6, Add. 578. 1764. 

 Annual herbs, with petioled purple or discolored leaves, and small flowers in loose 

 bracted racemes. Calyx campanulate, lo-nerved, 5-cleft, nearly regular in flower, enlarging, 

 declined and becoming 2-lipped in fruit, the upper lip 3-toothed, the lower 2-cleft, the throat 

 not bearded. Corolla-tube not longer than the calyx, the throat obliquely campanulate, the 

 limb 5-cleft, the lower lobe slightly the larger. Stamens 4, nearly equal, or the posterior 



