The Manual of the Botany of the Northern United States / Including the District East of the Mississippi and North of North Carolina and Tennessee

by Asa Gray

4. Ajuga. Corolla with a very short and as if truncate upper lip.

II. Nutlets smooth or granulate; scar basal, small; ovary deeply 4-parted.

Tribe II. SATUREINEÆ. Upper pair of stamens shorter or wanting; anthers 2-celled. Upper lip of corolla not galeate or concave.

[*] Flowers in loose terminal panicled racemes; calyx 2-lipped, enlarged and declined in fruit.

5. Collinsonia. Lower lobe of corolla fimbriate, much the largest. Stamens 2.

6. Perilla. Corolla short, the lower lobe little larger. Stamens 4, included.

[*][*] Flowers in more or less crowded clusters or whorls, axillary or spicate.

[+] Corolla not evidently 2-lipped, but almost equally 4-lobed, small. Stamens erect, distant.

7. Mentha. Fertile stamens 4, nearly equal.

8. Lycopus. Fertile stamens 2, and often 2 sterile filaments without anthers.