Tripterococcus Endl.
Enum.Pl. p17 (1837)

Name Status: Current
Browse to the list of specimens for Tripterococcus Endl.

Scientific Description
J. Gathe, Thursday 8 September 2016

Family Stackhousiaceae.

Habit and leaf form. Herbs. ‘Normal’ plants, or switch-plants. Leaves well developed, or much reduced (scale-like). Plants succulent, or non-succulent. Perennial. Young stems ribbed. Stem internodes solid. Rhizomatous (usually forming a perennial stock). Mesophytic, or xerophytic. Leaves alternate; spiral; ‘herbaceous’, or leathery, or fleshy, or membranous; petiolate to sessile; non-sheathing; simple; epulvinate. Leaf blades entire; solid; terete; linear, or lanceolate, or oblanceolate; ovate (broadly ovate to narrowly linear), or linear; one-veined, or pinnately veined. Leaves with stipules. Stipules interpetiolar; tiny, terete; caducous (sometimes), or persistent. Leaf blade margins entire. Leaf anatomy. Hairs absent. Extra-floral nectaries absent.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in spikes (slender, 1-sided). The terminal inflorescence unit cymose, or racemose. Inflorescences terminal. Flowers pedicellate (shortly, to almost sessile); bracteate (entire); bracteolate; regular to somewhat irregular. The floral asymmetry when detectable, involving the androecium. Flowers 5 merous; cyclic; tetracyclic. Free hypanthium present; campanulate (or cup-shaped); somewhat swollen, persistent in fruit. Hypogynous disk present (lining the calyx tube). Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; polysepalous (A), or gamosepalous (connate towards the base); entire, or lobed; when not entire, blunt-lobed; imbricate; regular, or unequal but not bilabiate. Sepals triangular (narrowly), or linear (narrowly), or ovate (to subulate). Calyx lobes triangular, or linear, or ovate (to subulate). Corolla present; 5; 1 -whorled; polypetalous, or gamopetalous; imbricate; tubular; unequal but not bilabiate, or regular; green (green-yellow), or yellow, or brown (brown-black). Petals narrowly triangular, or ovate to linear. Corolla lobes triangular, or ovate to linear. Petals clawed (the claws free, even when gamopetalous above). Androecial members definite in number. Androecium 5. Androecial members free of the perianth; markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 5; all more or less similar in shape; isomerous with the perianth; oppositisepalous (on the margin of the disc). Anthers dehiscing via longitudinal slits; tetrasporangiate; unappendaged. Gynoecium 3 carpelled. The pistil 3 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary plurilocular; 3 locular; sessile. Gynoecium stylate. Styles 1; attenuate from the ovary, or from a depression at the top of the ovary; apical. Stigmas as many as the carpels; 3 - lobed. Placentation axile to basal. Ovules 1 per locule; ascending; apotropous; with ventral raphe; anatropous.

Fruit and seed features. Fruit non-fleshy; a schizocarp (AKP). Mericarps 3; comprising nutlets. Fruit 3 seeded (1 per coccus). Seeds endospermic. Endosperm oily. Cotyledons 2. Embryo straight.

Etymology. From the Greek for "three", "wing", and "seed", alluding to the cocci in this genus.

Taxonomic Literature

  • Wheeler, Judy; Marchant, Neville; Lewington, Margaret; Graham, Lorraine (2002). Flora of the south west, Bunbury, Augusta, Denmark. Volume 2, dicotyledons. Australian Biological Resources Study. Canberra.
  • Grieve, B. J.; Blackall, W. E. (1998). How to know Western Australian wildflowers : a key to the flora of the extratropical regions of Western Australia. Part II, Dicotyledons (Amaranthaceae to Lythraceae). University of W.A. Press. Nedlands, W.A.
  • Marchant, N. G.; Wheeler, J. R.; Rye, B. L.; Bennett, E. M.; Lander, N. S.; Macfarlane, T. D.; Western Australian Herbarium (1987). Flora of the Perth region. Part one. Western Australian Herbarium. Perth.