GENUS 36. 



MINT FAMILY. 



12. Mentha gentilis L. Creeping or Downy 

 Whorled Mint. Spearmint. Fig. 3691. 



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

 Mentha saliva 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' long, the upper some- 

 times much smaller than the lower; whorls 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. PL 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, s"-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. PERIL-LA 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, S-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 



