462 LABIAT.E. 



94. LABIAT/E. Mint Family. 



Aromatic herbs or low shrubs with square stems and always oppo- 

 site simple leaves. Flowers solitary in the axils or more comm-only 

 in small cymes; cymes sessile in the axils of the opposite leaves 

 (rarely peduncled), commonly dense and having the appearance of a 

 whorl, and thus denominated in the descriptions. Subtending leaves 

 'if the whorls frequently bracf^like and the internodes short, the 

 inflorescence thus becoming spike-like, or the whorl sometimes termi- 

 nal and head-like; Calyx always synsepalous, frequently bilabiate, 

 usually 5-toothed. Corolla with a distinct tube, bilabiate, commonly 

 with 2 lobes in the upper lip and 3 lobes in the lower lip. Stamens 

 4, in 2 pairs, or the superior (upper) pair of stamens wanting or repre- 

 sented by sterile filaments. Ovary superior, 4-lobed (or 4-parted in 

 Triehostema), separating when ripe into 4 small 1-seeded nutlets. 

 Style single, situated in the depression among the lobes of the 

 ovary cleft at apex. Kutlets attached by the base (or by the side 

 in Triehostema). 



A. Flowers solitary in the axils; stamens 4. 

 Calyx with entire lips, a gibbous protuberance on the upper side 



2. SCDTELLARIA. 



Calyx not gibbous on the upper side (nor in any of the following). 

 Trailing herb; flowers very small. . . . . 12. Miceomep.ia. 



Slirub; flowers large. . . . 13. Sphacele. 



B. Flowers in whorls or terminal heads or axillary cymes. 

 1. Calyx regular, or its teeth nearly equal {except some species of Mentha). 

 Stamens with tbe exserted portion of filaments as long or longer than the 

 corolla, conspicuously curved; tube of corolla slender, abruptly curved 



below throat; ovary 4-lobed ; nutlets attached by the side 



1. Trichostema. 

 Stamens moderately exserted or Included ; ovary 4-parted ; nutlets attached 

 by the base, 

 Corolla little irregular. 

 Flower-whorls axillary. 

 Stamens 4; stems obtusely quadrangular; herbage aromatic . 



17. Mentha . 

 Stamens 2; stems acutely quadrangular ; herbage little aromatic. 



16. Lycopus. 

 Flowers in terminal bracted heads; segments of the corolla narrow and 

 very similar; stamens 4. ... , . . . 14. Monardella. 



Corolla plainly bilabiate-; stamens 4. 

 Stamens included In the tube of the corolla; calyx-teeth 10, subulate, 



hooked at tip; flowers in whorls . . . 3. Marrxjbium. 



Stamens projecting beyond the tube. 

 Inferior (lower) pair of stamens longer than the superior; calyx 

 tubular-campanulate, its teeth triangular, cuspidate; corolla- tube 

 wiih a hairy ring within; flowers in whorls. . 7, Stachys. 

 Stamens nearly equal; calyx tubular, its teeth very short, densely 



woolly; flower- whorls remote, mostly leafy-bracted 



15. KOELLIA. 

 Superior (upper) pair of stamens longer than the Inferior ; calyx-teeth 

 lanceolate, cuspidate, often pinkish; flowers in a dense spike. . . . 



5. IiOPHANTHUS. 



S. Calyx bilabiate or its teeth unequal. 

 Superior (Upper) pair of stamens longer than the inferior; calyx-teeth 



lanceolate-subulate 4. Nepeta. 



Inferior (lower) pair of stamens longer than the superior or latter wanting. 



