MONOPETALOUS EXOGENOUS PLANTS. 409 



* Calyx 2-lipped, closed in fruit. 



Lips of the calyx entire; the upper one appendaged. Flowers single, opposite. 



Scutellaria. 

 ** Calyx not 2-lipped ; the teeth or lobes spineless. 



Calyx 3-lobed. Flowers capitate, in crowded i-Jlowered whorls Macbredea. 



*** Calyx not 2-lipped ; the teeth rigid or spiny. 



Calyx-teeth 10, nearly equal. Stamens included. Herbs woolly MARRUBiuir. 



5. Nutlets truncate, sharp-angled. Leaves undivided Stachts. 



Tribe VI. Ajugeae. Stamens 4, ascending, parallel, 

 exserted. Nutlets reticulated and pitted, their bases par- 

 tially united within. 



Lobes of the corolla and calyx nearly equal. Peduncles 1-3-Jlcwered Isaktbvm. 



** Stamens long-exserted, didynamous. 

 Lobes of the corolla nearly equal. Calyx 5-cleft. Flowers solitary Trichostema. 



HYPTIS, Jacq. 



Calyx tubular, with 5 equal subulate teeth; corolla 

 5-lobed, the four upper lobes short, spreading or reflexed, 

 the lowest longer, saccate, abruptly deflexed, thickened at 

 the base; stamens 4, didynamous, included in the bud in 

 the lower lobe of the corolla ; nutlets smooth, ovoid. 



H. RADiATA, Willd. Herbaceous; stem erect, mostly 

 simple, pubescent above ; leaves ovate-lanceolate, serrate or 

 toothed, tapering into a petiole, smooth ; heads peduncled, 

 in the axils of the upper leaves, globose, surrounded by an 

 involucre of several lanceolate whitish bracts, pubescent ; 

 corolla small, white, dotted with purple. Low ground. 

 Stem 2°-4° high. 



MENTHA, L. Mint. 



Calyx tubular, nearly equally 5-toothed ; corolla equally 

 4-lobed, the upper lobe notched or entire; stamens 4, 

 equal, distant, straight; anther-cells ^tivoWol', style 2'Cleit 

 at the apex ; nutlets smooth, obtuse. — Pungent aromatic 



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