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.
Orchis ericeforum, W. R. Linton (= O. prcecox, Webst.). - This is more slender than O. maculata, of which it was regarded at first as a sub-species only (but see below. It is Linnasus's type). The stem is purple above. The leaves are narrower, more or less bent-back, the lower stem-leaves more or less long and narrow-pointed, keeled, and folded. The spike is 1-2 in., broadly pyramidal, at length oblong. The bracts are purple. The flowers are pale, not scented, with dark-purple markings, the ground colour commonly white or tinged with pink, but sometimes of deeper colour. The outer line of markings is nearly or quite complete. The honey-gland is slender, slightly enlarged (or not at all) upwards, and the throat is narrow. The lower lip is suborbicular, rounded in outline, rather spreading. The mid-lobe is much smaller than the broad, obliquely blunt or scalloped, lateral lobes, not exceeding them in length, and usually shorter or somewhat bent-back. This is true O. maculata, L., as recently defined by Mr. G. C. Druce.
This plant is found on wet heaths and marshy places. It differs from O. maculata (see Vol. II), from which it has recently been separated, in having a longer spike, not pyramidal, and in the form and markings of the lower lip. The leaves are narrower and also less spotted. The plant is taller, 1-1 1/2 ft. high, flowering from June to August, and is a herbaceous perennial.
Orchis O'Kellyi, Druce, has an oblong cylindrical spike. The lip consists of 3 narrow oblong segments. The middle segment is longer than the lateral ones, and becomes gradually narrow-pointed. The leaves are narrow, acute, keeled, unspotted. The flowers are white. The plant is 8-10 in. high, flowering from June to August, and is a herbaceous perennial.