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.
The habitat of this plant is bogs. The habit is the rosette habit. Regarded formerly as a subspecies of P. vulgaris, it has broader, larger leaves, and more oblong, inversely egg-shaped, rounded, contiguous calyx-lobes, with a rounded tip. The flowers are larger (hence grandifiora), violet-veined, the lobes of the lower lip very broad, overlapping. The spur is often divided into two nearly to the base, awl-like, conical to cylindrical, shorter than the corolla, as long as the calyx-lobes. The spur varies in length. The capsule is egg-shaped or rounded, rounded at the extremity. The plant is 4-6 in. high, flowering in May and June, and is a herbaceous perennial.
The habitat of this plant is bogs. The plant has the rosette habit, and is devoid of hairs except the scape. The radical leaves are oblong, shortly stalked, succulent, thin, blunt. The flowers are pale-pink or lilac, pale-yellowish in the throat, borne on slender, downy scapes. The short broad lobes of the corolla are equal, the lower pouched. The spur is broad, blunt, short, and conical or cylindrical, bent inwards, not so long as the corolla. The calyx-lobes are rounded. The capsule is more or less round. There are 2 cotyledons (1 in P. vulgaris). The plant is 2-4 in. high, flowering between June and October, and is a herbaceous perennial.
The habitat of this species is bogs. The plant has the rosette habit. It resembles the last, but is larger, and the scapes are not so long. The flowers are small, white, with a hairy, yellow throat, and the lobes of the corolla are unequal, the lower lip longer than the upper. The spur is conical, not so long as the corolla, broader and blunter, curved towards the lower lip. The calyx-lobes are broadly egg-shaped, blunt. The capsule is egg-shaped, acute. The plant is 2-4 in. high, flowering in May and June, and is a herbaceous perennial.