CLUSIACEAE (GUTTIFERAE) (St.
John’s Wort Family)
Plants annual or
perennial herbs or shrubs (trees and lianas elsewhere), sometimes more or less
evergreen, sometimes with rhizomes, usually glabrous, the tissues with clear to
yellowish to dark green or black resinous secretory cavities, these appearing
as dots, lines, or streaks on stems, leaves, and often also floral parts.
Leaves opposite, simple, sessile or short-petiolate. Leaf blades simple, the
margins entire. Stipules absent. Inflorescences terminal and/or axillary,
consisting of clusters of flowers, these often grouped into panicles, sometimes
reduced to single flowers, the branch points and flowers often subtended by
small, leaflike bracts. Flowers actinomorphic (except in a few Hypericum),
perfect, hypogynous. Calyces of 4 or 5 free sepals, usually persistent at
fruiting. Corollas of 4 or 5 free petals, these mostly spreading, sometimes
withered but persistent at fruiting. Stamens 5 to numerous, often in groups by
basal fusion of the filaments, the long, slender filaments occasionally fused
to the petal bases, sometimes fused into a short ring around the ovary base,
the anthers attached toward the base or more or less medially, yellow or
occasionally orange. Staminodes absent (in Hypericum) or glandular (in Triadenum).
Pistils of usually 2–5 fused carpels. Ovary superior, with 1–5
locules, with axile (when 2–5-locular) or parietal (when 1-locular)
placentation. Styles 1–5, persistent at fruiting, the stigmas capitate
or minute. Ovules numerous. Fruits capsules, the body narrowly to broadly ovoid
or nearly globose, usually tapered to a stylar beak(s), sometimes appearing
somewhat woody at maturity, dehiscing longitudinally. Forty-five to 50 genera,
900–1,350 species, nearly worldwide.
have treated the group of mostly temperate, herbaceous to shrubby species with
perfect flowers, relatively short secretory cavities, glandular-punctate
leaves, and seeds lacking arils as a separate family, Hypericaceae, restricting
the Clusiaceae to a mostly tropical group of shrubs and trees with usually
imperfect flowers, long secretory canals, leaves lacking glandular punctations,
and seeds often enclosed in fleshy arils. Studies of comparative anatomy,
especially of flower vascular patterns, have offered evidence that the entire
set of genera is best treated as a single family (summarized by Wood and Adams,
1976) comprising two or three subfamilies. There is general agreement, however,
that Hypericum and Triadenum are closely related and form a
natural group within this family.