LAMIACEAE 1049 



nun. long ; tube abruptly dilated at the throat ; lobes spreading : staminodia obsolete or 



minute : nutlets 1-1.5 mm. long, oblique at the apex. 



In low grounds, Newfoundland to British Columbia, North Carolina, Nebraska and Oregon. Sum- 

 mer and fall. 



3. Lycopus sessilifolius A. Gray. Green, glabrous, or slightly puberulent above. 

 Stems 2-6 dm. tall, with stolons and suckers : leaf-blades ovate to oblong or lanceolate, 

 acute or acutish, or slightly acuminate, 1.5-6 cm. long, shallowly serrate, sessile : bracts 

 minute : calyx campanulate ; lobes usually 5, rigid, subulate, about as long as the tube : 

 corolla white, about twice as long as the calyx : nutlets shorter than the calyx-lobes. 



In wet soil, Massachusetts to Florida. Summer and fall. 



4. Lycopus pubens Britton. Closely puberulent or pubescent, green or purplish. 

 Stems 6-12 dm. tall, rather obtusely angled, from long rootstocks and producing tuber- 

 bearing stolons : leaf-blades oblong, oblong-lanceolate or linear-oblong, acute or somewhat 

 acuminate, sharply serrate, sessile : calyx 2-2.5 mm. long, campanulate-turbinate ; lobes 

 lanceolate, fully as long as the tube : corolla twice as long as the calyx, puberulent : nut- 

 lets shorter than the calyx-lobes. 



In swampy pine lands, Georgia to Florida and Mississippi. Summer and fall. 



5. Lycopus ,rub611us Moench. Glabrous or finely puberulent, green or purplish 

 tinged. Stems 5-10 dm. tall, rather sharply angled, usually with scaly or leafy stolons : 

 leaf-blades oblong to elliptic, lanceolate or ovate-oblong, 3-15 cm. long, acuminate, sharply 

 serrate or dentate-serrate, petioled : bracts minute : calyx 2-5.3 mm. long ; lobes lanceo- 

 late or triangular-subulate, straight, herbaceous ; corolla fully twice as long as the calyx, 

 sparingly glandular-punctate : staminodia oblong or oval, or obsolete. 



In low grounds, New York to Ohio, Missouri, Florida and Louisiana. Summer and fall. 



6. Lycopus velutinus Rydb. Similar to L. ruhellus in habit, but copiously pubes- 

 cent, the stem and branches often densely so : leaf-blades elliptic, sometimes broadly so, to 

 elliptic-lanceolate, coarsely toothed, petioled or with petiole-like bases : calyx campanulate, 

 copiously pubescent, 2.5 mm. long ; lobes lanceolate, acuminate, longer than the tube, the 

 upper two, at least, recurved : corolla 3.5 mm. long, copiously glandular-punctate : nutlets 

 surpassing the calyx-tube. 



In low grounds and swamps, Colorado to Texas and Mississippi. Summer and fall. 



7. Lycopus Americanus Muhl. Glabrous or puberulent, green. Stems 1-9 dm. 



tall, sharply angled : leaf-blades lanceolate to ovate-lanceolate, 2-10 cm. long, acuminate, 



incised or pinnatifid, or those on the upper part of the stem merely toothed : calyx 2-3 mm. 



long ; lobes lanceolate to triangular-subulate, rigid : corolla but little longer than the calyx : 



staminodia thickened at the apex : nutlets slightly longer than the calyx-tube. 



In wet soil or meadows, Newfoundland to British Columbia, Florida, Texas and California. Sum- 

 mer and fall. 



38. MENTHA L. 



Perennial herbs, Avith erect or diffuse stems and aromatic herbage. Leaves opposite : 

 blades flat, punctate, toothed or incised, often petioled. Flowers in dense remote or con- 

 tiguous clusters. Calyx often punctate : tube campanulate to tubular, lO-ribbed : lobes 5, 

 equal or nearly so. Corolla white, pink or purple, nearly regular : tube surpassed by the 

 calyx : lobes unequal, the upper larger than the rest, entire or emarginate. Stamens 4, 

 erect : filaments equal : anthers 2-celled ; sacs parallel. Nutlets smooth. Mint. 



Flower-clusters axillary. 



Calyx-lobes triangular. 1. M. arvensis. 



Calyx-lobes subulate or lanceolate. 



Calyx with ciliate lobes and a glabrous or nearly glabrous tube. 2. M. gentilis. 



Calyx closely pubescent all over. 3. M. Canadensis. 



Flower-clusters collected into terminal raceme-like or spike-like panicles. 

 Foliage glabrous. 



Panicles less than 1 cm. thick. 4. M. spicata. 



Panicles over 1 cm. thick. 



Leaf-blades fully twice as long as broad, narrowed at the base. 5. M. piperita. 



Leaf-blades nearly as long as broad, truncate or subcordate at the base. 6. M. citmta. 



Foliage copiously pubescent. 7. M. rotundifolia. 



1. Mentha arvensis L. Stems 1.5-6 dm. tail, sometimes decumbent, closely pubes- 

 cent. Leaf-blades oblong, oblong-lanceolate, oval or ovate, 2-6 cm. long, shallowly ser- 

 rate or cuneate-serrate, short-petioled : clusters axillary : calyx 2-3 mm. long, finely pubes- 

 cent ; tube campanulate ; lobes triangular, each about as long as the width of the base, or 

 J as long as the tube : corolla bright pink, 4-5 ram. long. 



In waste places or on river banks. New Brunswick to New York and Florida. Also in California 

 and Mexico. Naturalized from Europe. Summer and fall. 



