Perennial. — Flowers in July and August. 
Root creeping, producing many shoots, which become tuberous 
towards the Autumn, and render the plant difficult of extirpation. 
Stem 2 feet high, upright, branched, 4-angled, hollow ; clothed, 
especially at the angles, with stiffish hairs, which turn downwards ; 
jointed, joints hairy, and often purplish. Leaves opposite, strap- 
spear-shaped, serrated, spreading, somewhat wrinkled, silky above, 
downy beneath, the ribs roughish with reflexed bristles ; sessile, 
and slightly embracing the stem, or on very short leaf stalks. Flowers 
of a pale purple, variegated with violet and white, and arranged in 
whorls of from 6 to 10 flowers, forming a lax spike, each whorl of 
which is accompanied by a pair of small deflexed leaves. Calyx 
of one leaf, somewhat bell-shaped, cut into 5 nearly equal, sharp- 
pointed teeth, hairy, hairs terminating in small globules ; purplish, 
and marked with 10 elevated lines. Corolla of one petal, gaping, 
tube very short, cylindrical, crowned internally with hairs ; mouth 
marked with 2 prominent dots at the base of the upper lip ; lower 
lip beautifully variegated with violet and white. Filaments hairy, 
thickest in the middle. Anthers purplish-black ; Pollen white. 
Germen angular, 4-lobed. Style thread-shaped, the length of the 
stamens. Stigma bifid, pointed. Seeds somewhat triangular, en- 
closed in the permanent calyx. 
A few years ago (about 1818?) the Society of Arts voted the 
silver Ceres medal to Joseph Houlton, Esq. F. L. S., &c. for 
introducing this plant to public notice. The thick tuberous buds 
formed on the roots of this species, and from which the stems of the 
next year are to arise, abound, from the end of autumn to the close 
of winter, in a mild, somewhat sweetish, farinaceous matter ; these 
tubers, it is said, are then fit for domestic use, being crisp, without 
fibre, and of a peculiar, but scarcely perceptible flavour. The Rev. 
Mr. Lightfoot informs us, in his Flora Scotica, v. ii. p. 313, that 
in times of necessity they have been eaten by men, either boiled, or 
dried, and made into bread ; but Mr. Houi.ton has the credit of 
having first suggested its use as an esculent vegetable, and of having 
made some experiments on the best way of cultivating it. This is 
supposed to be the only known instance of a plant belonging to the 
Natural Order of the Labiate, producing farinaceous tubers, capa- 
ble of being applied to human food. See Loud. Gard. Mag. vol. v. 
p. 546. 
On account of its extensively creeping roots it is often a great 
pest to the farmer, especially in cornfields in low moist situations. — 
Hogs are said to be fond of the roots ; and Mr. Curtis thought, 
that when the crop was off they might be turned into those fields 
where the plant abounds, to great advantage. 
