General description:- Shrubs or herbs, with translucent glands containing essential oils and sometimes red or black glands containing hypericin.
Leaves:- Simple, opposite, or rarely in whorls of 3-4.
Flowers:- Actinomorphic. Sepals (imbricate) in bud. Petals free, contorted in bud. Stamens in fascicles or apparently indefinite. Ovary superior. Placentation axile or parietal.
Fruit:- Seeds without endosperm.
HYPERICUM
Flowers:- Hermaphrodite. Sepals (4-)5. Petals (4-)5, yellow, sometimes tinged with red. Stamens in 3 or 5 fascicles (cluster of similar organs) of (1-)3 to c. 125, sometimes alternating with sterile fascicles (fasciclodes), or in 5 irregular groups; fascicles, if 5, opposite to a petal (antepetalous); if 3, one antepetalous and two (larger) opposite to a sepal (antesepalous). Ovary (2-)3- to 5-celled (5-locular) or partly or completely 1-locular; ovules numerous. Styles (2-)3-5, free, slender.
Fruit:- A septicidal capsule (the ripe capsule splits along the lines of junction of the carpels, i.e. along the septa, the fruit valves remaining attached and not falling off.), rarely fleshy and more or less indehiscent (fruits that do not split open to release their seeds).
Glands are designated marginal if they protrude sufficiently to interrupt the line of the margin of a leaf, sepal or petal, intramarginal if they abut on the margin but do not interrupt its line, superficial if they are quite clear of the margin.
In many species the ovary and capsule have glandular streaks or patches on the wall. These are referred to as vittae if flat or slightly swollen, and as vesicles if conspicuously swollen. vittae on or near the midrib of a carpel are described as dorsal.
Sect. ANDROSAEMUM
General description:- Glabrous shrubs, without black glands.
Stems:- 2-lined or 4-angled.
Leaves:- Opposite.
Flowers:- In few-flowered, terminal cymes. Sepals entire. Petals and stamens deciduous. Stamen-fascicles 5. Styles 3(-4).
Fruit:- More or less fleshy at first, tardily dehiscent. Seeds reticulate, winged.
Sect. CORIDIUM
General description:- Shrubs or perennial herbs, glabrous or with papillose leaves. Black glands confined to sepals, or rarely absent.
Leaves:- Whorled, usually linear; margins revolute.
Flowers:- In cymes, rarely solitary. Sepals usually with glandular margin. Stamen-fascicles 3. Styles 3.
Fruit:- Capsule with longitudinal vittae or oblique vesicles. Seeds papillose or rugulose.
Sect. DROSOCARPIUM
General description:- Perennial herbs, usually glabrous and somewhat glaucous. Black glands present on leaves, sepals, petals, anthers, and sometimes ovary.
Leaves:- Usually with intramarginal and often superficial black glands.
Flowers:- In subcorymbose or broadly pyramidal panicles, rarely solitary. Petals and stamens persistent. Stamen-fascicles 3(-5). Styles 3(-5).
Fruit:- Capsule with interrupted lateral vittae or vesicles, sometimes with dorsal vittae. Seeds longitudinally ribbed, with transverse striation.
Sect. TRIADENIA
General description:- Dwarf, glabrous, microphyllous shrubs, without black glands.
Leaves:- Opposite
Flowers:- Terminating long or short shoots, heterostylous. Sepals entire. Petals with entire, ligulate, nectariferous appendage. Stamen fascicles 3, with filaments united for more than ½ their length, alternating with 3 fleshy fasciclodes
Fruit:- Dry. Seeds slightly carinate, with fleshy caruncle.