This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
1. Perforate St. John's Wort (Hypericum perforatum, L.). 2. Herb Robert (Geranium Robertianum, L.). 3. Spindle Wood (Euonymus europieus, L.). 4. Tufted Vetch (Vicia Cracca, L.). 5. Meadow Vetchling (Lathyrus pratensis, L.). 6. Blackthorn (Prunus spinosa, L.).
Photo. Flatters & Garnett - Perforate St. John's Wort (hypericum Perforatum, L.)
The leaves are small, stalkless, oblong, with scattered semi-transparent dots, perforated. The under side is covered with black dots The dots contain oil, and may protect the plant from cattle. The sepals are erect, acute, and entire, the petals oblong, the flowers yellow, the margins of the sepals entire, without glands, whilst there are black dots on the petals.
The petals are notched. The three styles equal the capsule, and the stigmas are simple. The anthers are crowned with black glands.
The plant is 18 in. in height in many cases. The flowering season is from July to September. It is perennial, and can be increased by division.
The flowers are conspicuous and yet have no honey, and are adapted for self-pollination. They contain plenty of pollen. There are three groups of stamens united below, of different lengths, with anthers directed upwards which open in quick centrifugal succession outwards, and are immersed in pollen, the shortest opening first, the longest last. There are 3 styles, which radiate outwards. The stigmas developed at the same time are terminal, and on a level with the longest anthers between the groups of stamens. The stamens (in bundles) touch or are interwoven at the margin, and the stigmas may touch the pollen-covered anthers. Insects settle on one of the 5 outspread petals, and reach the anthers between two groups of stamens, and bring about either cross-pollination if they touch the stigma first, or self-pollination if they touch the anthers first. The petals and stamens later become erect, and self-pollination follows in the absence of insect visitors.
The visitors are Hymenoptera (Apidae, Tenthredinidae), Diptera (Bombylidae, Empidae, Syrphidae), Lepidoptera (Large Skipper, Hes-peria sylvanus, Meadow Brown, Satyrus Janira), Coleoptera (Chry somelidae).
The seeds of this plant are dispersed by its own mechanism. The capsule is erect, opening at the top, splitting along divisions, and the seeds are dispersed by breaking up of the valves, and to some extent by the wind. The seeds are oblong or elliptic, netted, and dark brown.
It is a humus-loving plant, and requires a humus soil.
The fungus Melampsora hypericorum infests it. The beetles Chrysomela fucata, Cryptocephalus 10-punctatiis, the moths Purple Cloud (Cloantha perspicillaris), Black-veined Moth (Scoria dealbata), Treble-bar (Anaitis plagiata), Nepticula septembrella, Satyr Pug (Eupithecia Satyrata), Grapholite Hypericana, Gracilaria acuoguttella, Ringed Carpet (Boarmia cinctaria), the Homopteron Aphis papaverii, and the gall-fly Cecidomyia serotina feed on it.
Hypericum, Dioscorides, is from the Greek hyper, over, ereike, heath, and perforatum (Latin) refers to the perforate leaves.
Perforate St. John Wort is called Amber, Balm of Warrior's