Name: Tetracarpaea refers to the four conspicuous and separate carpels.
Region: Tasmania.
Habitat: subalpine areas.
BotanyEvergreen, glabrous, erect, bushy, beautiful, little shrub; from 15 to 100 cm.
Leaves: shiny; small; with prominent veins and end near the margin; elliptic to oblanceolate; ± 25 mm long and 8 mm wide; petiole about 2 mm long; margins are serrate or crenate; epidermis is covered by a thick cuticle.
Inflorescences: dense, erect, terminal racemes, up to 5 cm long.
Flowers: small, white; bisexual, actinomorphic, and 5 to 10 mm wide; crowded at the ends of the branches; blooming in autumn; 4 sepals persist to the maturity of the fruit; 4 petals are white and spatulate in shape; stamens are 4 and opposite or 8; anthers are basifixed; ovary is superior, with 4 large carpels, usually separate, occasionally 2 or 3 fused at the base, or rarely halfway up, erect and stipitate, with a suture along the ventral side; placenta runs along each side of the suture and bears 1 to 3 rows of numerous, tiny ovules; ovules have one integument or two; ovary hardly enlarges after anthesis.
Fruit: of 4 follicles; joined at the base.
Seeds: numerous; ±.5 mm long.
TaxonomyTetracarpaea has an odd mix of characters, and its affinities remained obscure. It is the only genus in the flowering plant family
Tetracarpaeaceae. William Jackson Hooker placed it near
Cunoniaceae. George Bentham also placed it in the
Cunoniaceae, but later
moved it to
Escalloniaceae. Adolf Engler put Tetracarpaea in
Saxifragaceae, including
Escalloniaceae.Later most authors put Tetracarpaea in
Cunoniaceae,
Escalloniaceae, or
Saxifragaceae. Takenoshin Nakai put Tetracarpaea in its own family
Tetracarpaeaceae. Arthur Cronquist put Tetracarpaea in
Grossulariaceae. Armen Takhtajan has at different times put Tetracarpaea in
Escalloniaceae and in
Tetracarpaeaceae. Matthew H. Hils concluded that Tetracarpaea was much closer to
Saxifragaceae than to
Cunoniaceae or
Escalloniaceae. Phylogenetic analysis of DNA sequences has shown that Tetracarpaea is a member of the
Haloragaceae alliance, an informal group composed of the families
Aphanopetalaceae,
Tetracarpaeaceae,
Penthoraceae, and
Haloragaceae in the order
Saxifragales.
TaxonomyHooker named Tetracarpaea and placed it in
Cunoniaceae. George Bentham moved Tetracarpaea from
Cunoniaceae to
Escalloniaceae. Adolf Engler put Tetracarpaea in
Saxifragaceae. Takenoshin Nakai put Tetracarpaea in its own family
Tetracarpaeaceae. John Hutchinson placed it in
Escalloniaceae. Arthur Cronquist put Tetracarpaea in
Grossulariaceae. Armen Takhtajan has at different times put Tetracarpaea in
Escalloniaceae and in
Tetracarpaeaceae.