Perennial. — Flowers from April to November. 
Root white, jointed, creeping. Stems numerous, upright, un- 
branched, about a foot or eighteen inches high, slender at bottom, 
square, hollow, more or less hairy, frequently cf a reddish purple 
colour ; the young shoots weak and ascending. Leaves opposite, 
heart-shaped, pointed, strongly serrated, deep green, unspotted, 
stalked, veiny and hairy, those about the root frequently small, 
round and crenated. Leaf-stalks ( petioles ) broader at the base, 
longer on the leaves next the root. Flowers large, from 10 to 20 in 
a whorl, white, rarely tinged with red, hairy, lip cream coloured. 
Calyx sessile, slightly ten ribbed, hairy, with five bristly pointed 
teeth, marked on the lower side at bottom with dark purple spots, 
and supported by a short strap-shaped floral-leaf. Corolla twice as 
long as the calyx, upper lip arched, hairy, with a slight notch, mouth 
with a small spear-shaped tooth on each side ; lower lip bifid, turned 
back, slightly notched, and spotted at bottom. Anthers black, 
hairy. Pollen yellow. 
The whole plant, when handled, or bruised, has a disagreeable 
smell, and is scarcely ever eaten by cattle, but it is much resorted to 
by bees, for the sake of the honey, which it secretes in considerable 
quantity at the base of the tube of the corolla ; on this account Dr. 
Withering recommends it to be encouraged in the precincts of the 
apiary. 
It is not now used in medicine, though it was formerly considered 
useful in disorders of the lungs. — Boys make whistles of the stalks. 
It increases very fast by its strong creeping roots, but as they run 
horizontally near the surface of the ground, the plant is easily ex- 
tirpated. 
The class and order Didynamia Gymnospermia consists of plants 
which are all either herbaceous or shrubby, with square, branched, 
leafy stems; and opposite, simple, entire or serrated, sometimes 
divided, leaves ; never with any stipulas. The flowers are either 
solitary, or in opposite, nearly sessile, axillary clusters, or dense 
tufts, resembling whorls; their colour reddish, purple, blue, 
white, or yellow. The qualities of these plants are aromatic 
or bitter; and their herbage, especially the leaves and calyx, is 
furnished with round pellucid dots or pores, which are the seat of 
an aromatic essential oil. The pubescence, in many species, exudes 
a similar, or more viscid, or a bitter secretion. Sometimes the 
growing parts are attacked by insects for the lodgement of their 
eggs, and then these secretions are changed to acid or astringent 
ones. The plants of this order (Gymnospermia) are all harmless, 
not a single unwholesome, or even suspicious species having been 
found amongst them. 
