Herbs with square stems, opposite leaves (mostly aromatic), didynamous (or in one or two genera diandrous) stamens, a 2-lipped or irregularly 4-or 5-lobed corolla, and a deeply 4-lobed ovary, forming in fruit 4 nutlets or achenes. (See Part I., Section 65, for description of a typical plant.)

Synopsis Of The Genera

* Stamens 4, curved upwards, parallel, exserted from a deep notch on the upper side of the 5-lobed corolla.

1. Teu'crium. Calyx 5-toothed. The four upper lobes of the corolla nearly equal, with a deep notch between the upper 2; the lower lobe much larger. Flowers pale purple.

2. Isan'thus. Calyx bell-shaped, 5-cleft, almost equalling the small pale-blue corolla. Lobes of the corolla almost equally spreading. Stamens only slightly exserted.

* * Stamens 4, the outer or lower pair longer, or only 2 with anthers, straight and not converging in pairs ! Anther's 2-celled !

+ Corolla almost equally 4-lobed, quite small.

3. Men'tha. Calyx equally 5-toothed. Upper lobe of the corolla rather the broadest, and sometimes notched. Stamens 4, of equal length, not convergent. Flowers either in terminal spikes or in head-like whorled clusters, often forming interrupted spikes. Corolla purplish or whitish.

4. Lyc'opus. Calyx-teeth 4 or 5. Stamens 2, the upper pair, if any, without anthers. Flowers white, in dense axillary clusters.

+ + Corolla evidently 2-lipped, but the lobes nearly equal in size; the tube not bearded inside. Stamens with anthers 2.

5. Hedeo'ma. Calyx 2-lipped, bulging on the lower side of the base, hairy in the throat ; 2 stamens with good anthers, and 2 sterile filaments with false anthers. Low odorous plants, with bluish flowers in loose axillary clusters.

+ + + Corolla 2-lipped, the lower of the 5 lobes much larger than the other 4; the tube with a bearded ring inside. Stamens 2

{occasionally 4), much exserted.

6. Collinso'nia. Calyx ovate, enlarged and turned down in fruit, 2lipped. Corolla elongated, the lower lip toothed or fringed. Strong-scented plants with yellowish flowers on slender pedicels in terminal panicled racemes.

+ + + Corolla evidently 2-lipped. Stamens with anthers 4.

7. Hysso'pus. Calyx tubular, 15-nerved, equally 5-toothed. Corolla blue-purple, short; upper lip erect, flat, obscurely notched, the . lower 3-cleft, with the middle lobe larger and 2-cleft. Stamens exserted, diverging. Flowers in small clusters, crowded in a spike. Branches simple, wand-like.

8. Pycnan'themum. Calyx short-tubular, 10-13-nerved, equally 5toothed. The whitish or purplish flowers in small dense heads, forming terminal corymbs. Aromatic plants, with narrow rigid leaves crowded and clustered in the axils.

9. Sature'ia. Calyx bell-shaped, not hairy in the throat, equally 5toothed. Aromatic plants, with narrow leaves and purplish spiked flowers.

* * * Stamens only 2, parallel; the anthers only 1-celled. Corolla 2-lipped.

10. Monar'da. Calyx tubular, nearly equally 5-toothed, hairy in the throat. Corolla elongated, strongly 2-lipped, the upper lip narrow. Stamens with long protruding filaments, each bearing a linear anther on its apex. Flowers large, in whorled heads surrounded by bracts.

* * * * Stamens 4, the upper or inner pair longer! Anthers approximate in pairs. Corolla 2-lipped.

11. Nep'eta. Calyx obliquely 5-toothed. Anthers approaching each other in pairs under the inner lip of the corolla, the cells of each anther divergent.

12. Dracoceph'alum. Calyx straight, 5-toothed, the upper tooth much the largest. Whorls of bluish flowers with awn-toothed or fringed leafy bracts, in a crowded head or spike.

13. Lophan'thus. Calyx obliquely 5-toothed. Stamens exserted, the upper pair declined, the lower ascending, so that the pairs cross. Anther-cells parallel. Tall herbs with small flowers in interrupted terminal spikes.

***** Stamens 4, the lower or outer pair longer! Anthers approxi-* mate in pairs. Corolla 2-lipped.

14. Calamin'tha. Calyx tubular, 2-lipped, often bulging below. Corolla 2-lipped, the upper lip not arched, the throat inflated. Flowers pale purple, in globular more or less dense clusters which are crowded with linear or awl-shaped hairy bracts.

15. Melis'sa. Calyx with the upper lip flattened and 3-toothed, the lower 2-cleft. Corolla nearly white, the tube recurved-ascending. Stamens curved and conniving under the upper lip. Flower-cluster loose, few-flowered, one-sided, with few bracts resembling the leaves.

16. Physoste'gla. Calyx not 2-lipped, 5-toothed or lobed, thin and membranaceous, inflated-bell-shaped in fruit. Anther-cells parallel. Flowers large and showy, rose-colour variegated with purple, opposite, in terminal leafless spikes.

17. Brunei 'la. Calyx 2-lipped, flat on the upper side, closed in fruit; the upper lip 3-toothed, the lower 2-cleft. Filaments 2-toothed at the apex, the lower tooth bearing the anther. Flowers violet, in a close terminal spike or head, which is very leafy-bracted.

18. Scutellaria. Calyx 2-lipped, short, closed in fruit, the lips rounded and entire, the upper with a projection on the back. Corolla blue or violet, the tube elongated and somewhat curved. Anthers of the lower stamens 1-celled, of the upper 2-celled. Flowers solitary in the axils of the upper leaves, or in axillary or terminal 1-sided racemes.

19. Marru'bium. Calyx 10-toothed, the teeth spiny and recurved after flowering. Stamens 4, included in the corolla tube. Whitish woolly plants with small white flowers in head-like whorls.

20. Galeop'sis. Calyx 5-toothed, the teeth spiny. The middle lobe of the lower lip of the corolla inversely heart-shaped, the palate with 2 teeth at the sinuses. Stamens 4, the anthers opening cross-wise. Flowers purplish, in axillary whorls.

21. Stach'ys. Calyx 5-toothed, beset with stiff hairs, the teeth spiny, diverging in fruit. Stamens 4, the outer pair turned down after discharging their pollen. Flowers purple, crowded in whorls, these at length forming an interrupted spike. '

22. Leonu'rus. Calyx 5-toothed, the teeth spiny, and spreading when old. The middle lobe of the lower lip of the corolla narrowly oblong-obovate, entire. Flowers pale purple, in close whorls in the axils of the cut-lobed leaves. Nutlets sharply 3-angled.

23. La'mium. Calyx tubular bell-shaped, 5-nerved, with 5 nearly equal awl-pointed teeth. Corolla dilated at the throat; upper lip arched and narrowed at the base, the middle lobe of the lower lip notched at the apex and narrowed at the base. Herbs with purple flowers in few or several whorls or heads.

24. Rallota. Calyx nearly funnel-form, 10-ribbed, with a spreading 5-toothed border. Whorls of purplish flowers dense. Anthers exserted. Plant erect, hairy (but green).