1. P. Leptostàchya, L. Plant 2–3° high; leaves 3–5´ long, thin; calyx strongly ribbed and closed in fruit, the long slender teeth hooked at the tip.—Moist and open woods, common. (E. Asia.)
Order 82. LABIÀTÆ. (Mint Family.)
Chiefly herbs, with square stems, opposite aromatic leaves, more or less 2-lipped corolla, didynamous or diandrous stamens, and a deeply 4-lobed ovary, which forms in fruit 4 little seed-like nutlets or achenes, surrounding the base of the single style in the bottom of the persistent calyx, each filled with a single erect seed.—Nutlets smooth or barely roughish and fixed by their base, except in the first tribe. Albumen mostly none. Embryo straight (except in Scutellaria); radicle at the base of the fruit. Upper lip of the corolla 2-lobed or sometimes entire; the lower 3-lobed. Stamens inserted on the tube of the corolla. Style 2-lobed at the apex. Flowers axillary, chiefly in cymose clusters, these often aggregated in terminal spikes or racemes. Foliage mostly dotted with small glands containing a volatile oil, upon which depends the warmth and aroma of the plants of this large and well-known family.
I. Nutlets rugose-reticulated, attached obliquely or ventrally; ovary merely 4-lobed.
Tribe I. AJUGOIDEÆ. Stamens 4, ascending and parallel, mostly exserted from the upper side of the corolla. Calyx 5–10-nerved.
[*] Limb of corolla merely oblique, of 5 nearly equal and similar lobes.
1. Trichostema. Corolla lobes all declined. Calyx oblique. Stamens exserted.
2. Isanthus. Calyx bell shaped. Corolla small, the lobes spreading. Stamens included.
[*][*] Limb of corolla irregular, seemingly unilabiate, the upper lip being either split down or very short; stamens exserted from the cleft.
3. Teucrium. Corolla deeply cleft between the 2 small lobes of the upper lip.