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.
This plant is not found in seed-bearing beds. It is a plant of the Northern Temperate Zone, found in Arctic Europe, eastwards to Lithuania and Turkey. In Great Britain it is generally common, but does not occur in Hunts, Radnor, Montgomery, Merioneth, Peebles, Selkirk, Stirling, Mull, or West Ross, and ascends to a height of 2200 ft. in the Highlands.
The Pretty St. John's Wort, a plant not belying its name, is an ericetal species, which is found on high ground in copses and along hedges, where the soil is more or less dry, for it is practically xero-philous. But another and more typical habitat is heathland or common-land, where it grows in company with Grassy Stitchwort, Sheep's Bit Scabious, Red Rattle, Common Sylvan Cow-wheat, and Heath Hair Grass.
This is an erect, slender, tall-stemmed plant, smooth, with similar branches, which are few and distant, the stem-leaves heart-shaped to egg-shaped, shining, rigid, clasping, perforate, the upper ones not so long. The plant generally grows in isolated patches. The flowers are in loose cymes, yellow, tinged with red, of a beautiful golden colour, with 5 petals and 5 broad, blunt, entire sepals fringed with black glands or black glandular teeth, half as long as the petals, which are glandular and fringed with black glands. The anthers are red, the styles 3. The filaments (36) are united below in three bundles. The capsule is 3-chambered, subconical.
This plant is often 18 in. high. It flowers in July and August. It is perennial, and a deciduous, herbaceous plant increased by division of the root.
The flowers are more conspicuous than in Perforate St. John's Wort, and cross-pollination is more assured than in the latter. Otherwise the two plants have a very similar floral mechanism adapted to the same end. There is no honey, but much pollen. Seeds are dispersed by the plant's own agency. The capsule is septicidal, and the seeds are dispersed by breaking up of the valves, aided by the wind.
Pretty St. John's Wort is a rock-loving plant and addicted to a rock soil, which is derived from older rocks.
Photo. Flatters & Garnett - Pretty St. John's Wort (Hypericum pulchrum, L.)
The beetles Libia cyanocephala, Cryptocephalus moroei, Chrysomela hyperici feed on St. John's Wort.
The flowers are prettier than those of some of the other species (hence the Latin name pulchrum), and are tinged with red.
Essential Specific Characters: 62. Hypericum pulchrum, L. - Stem erect, single, terete or round in section, glabrous, leaves cordate, clasping, smooth, the upper oblong, flowers golden-red, sepals and petals also obtuse, fringed with stalked glands.