This section is from the book "British Wild Flowers - In Their Natural Haunts Vol5-6", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Wood Calamint (Satureia (Calamintha) sylva-tica, Bromf. = 5. grandiflora, Sch. = C. officinalis, Moench). - The habitat of this plant is bushy places and chalk banks. The habit is somewhat creeping. The branches are long, ascending (or not). The stem is nearly simple, wavy. The leaves are broadly egg-shaped, scalloped, toothed, large. The flowers are large, in loose, many-flowered cymes, the common stalk as long as the primary partial stalk. The calyx is tubular, 2-lipped, the upper teeth turned back, fringed with hairs, purple-tinged, bent on the stalk. The lower lip of the large purple corolla has touching or overlapping lobes, long, nearly equal, the middle lobe short and broad, nearly equalling the lateral, the tube projecting far, and twice as long as the calyx. The plant is 1-2 ft. high, flowering in August and September, and is a herbaceous perennial.
The habitat of this plant is dry gravelly banks, sandy coasts. The plant has the rosette habit. It is more slender than 5. Verbenaca. The leaves are stalked, narrower, heart-shaped, oblong, wavy-toothed, the upper oblong, acute. The calyx-teeth are stalkless, the upper are less spiny, small, the corolla longer than the calyx, more purple or pale-blue, the upper lip longer, arched. The plant is 1 ft. high, flowering in July, and is a herbaceous perennial.