144-184 species in six genera. Sebaea is the largest genus.
World tropics, mainly in tropical Africa, Madagascar and India.
Annual herbs to subshrubs up to a few meters tall, or tiny
saprophytic plants (Cotylanthera).
often winged or with four lines. Flowers solitary, or
inflorescences few or many-flowered mono- or dichasial terminal or
axillary cymes. Flowers 4-merous or most commonly 5-merous, rarely
zygomorphic by having fused anthers above a bent style. Calyx
sometimes distinctly winged. Corollas white to blue/violet, or white to
yellow. Corolla tube rather short and funnelshaped to urceolate or
long-cylindric, rarely long and narrowly funnelshaped). Anthers dehiscent
by longitudinal slits or by one or two apical pores (Exacum),
often with apical appendages. Pollen in monads. Ovary usually without a
nectary disc below it, is bilocular with axile placentas or
unilocular but becoming pseudo-bilocular from the
centrally-protruding parietal placentas. Fruit is a thin capsule. Seeds
are usually angular with slightly to much undulated and often star-shaped
testa cell walls.
and related plants:
uses: Exacum affine (persian violet) is commercially
cultivated as a pot plant.
Exacum L. (images)
Sebaea Sol. ex R. Br. (images)
J. 1985. The genus Exacum (Gentianaceae). Opera Bot. 84: 1-144.
J. 1986. The new genus Ornichia (Gentianaceae) from Madagascar. Bull.
Mus. Nat. Hist. Nat.,
Paris, 4 sér., 8, sect. B, Adansonia, 2: 195-206.
J. 1987a. Revision of the genus Tachiadenus
(Gentianaceae). Bull. Mus. Nat.. Hist. Nat. Paris , 4 sér., 9, sect. B,
Adansonia 1: 43-80.
L., J. W. Kadereit, J. Klackenberg, S. Nilsson, M. Thiv, K. B. von Hagen,
& V. A. Albert. 2002. Systematics, character evolution, and
biogeography of Gentianaceae, including a new tribal and subtribal
classification. Pp. 21-309. In: L. Struwe & V. A. Albert (eds.),
Gentianaceae: Systematics and Natural History, Cambridge University Press,
© Lena Struwe, 2003