Exocarpos Labill.
Voy.Rech.Pérouse p155, t. 14. (1800)

Name Status: Current
Browse to the list of specimens for Exocarpos Labill.

Scientific Description
J. Gathe and Leslie Watson, Thursday 8 September 2016

Common name. Ballarts. Family Santalaceae.

Habit and leaf form. Trees, or shrubs. More or less ‘normal’ plants, or switch-plants; sometimes with the principal photosynthesizing function transferred to stems. Leaves well developed, or much reduced (often). Plants with roots, or rootless; partially parasitic. On roots of the host. Stem internodes solid. Mesophytic, or xerophytic. Leaves alternate (usually), or opposite (rarely); ‘herbaceous’, or membranous (persistent or caducous); sessile; gland-dotted, or not gland-dotted; aromatic, or without marked odour (? — E. odoratus); simple; pulvinate. Leaf blades entire; scale-like; one-veined, or pinnately veined. Leaves without stipules. Leaf blade margins entire. Leaf anatomy. Hairs present. Extra-floral nectaries absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite, or hermaphrodite and functionally male. Unisexual flowers present, or absent. Plants hermaphrodite, or andromonoecious. Male flowers with pistillodes.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in fascicles (or clusters). The terminal inflorescence unit cymose, or racemose. Inflorescences axillary; racemes often small and spike-like or contracted to a cluster, 1 only or rarely 2 or 3 flowers in the spike fertile with the pedicel rapidly enlarged, the others falling off without any enlargement of the semi-abortive ovary. Flowers pedicellate, or sessile (sessile or almost so); bracteate (minute, subtends flowers); ebracteolate; small; regular; (4–)5 merous; cyclic; tricyclic. Free hypanthium present, or absent; KPB describe a floral tube in the Santalaceae but without reference to Exocarpos. Perianth sepaline; (4–)5; 1 -whorled; free, or joined (the lobes valvate); sepaloid; greenish yellow, or green; fleshy, or non-fleshy; persistent, or deciduous. Calyx (‘calycode’) (4–)5; 1 -whorled; polysepalous; valvate; regular; greenish yellow, or green; fleshy, or non-fleshy; persistent, or not persistent. Androecial members definite in number. Androecium (4–)5. Androecial members free of the perianth, or adnate; all equal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens (4–)5; all more or less similar in shape; isomerous with the perianth; oppositisepalous (opposite the perianth segments, near their bases). Anthers basifixed; dehiscing via longitudinal slits; introrse; bilocular; tetrasporangiate. Fertile gynoecium present, or absent (male flowers). Gynoecium (2–)3(–5) carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth to isomerous with the perianth. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; superior. Ovary unilocular; 1 locular; sessile. Gynoecium non-stylate, or stylate. Styles 1; apical. Stigmas 1; capitate (or lobed). Placentation free central. Ovules differentiated to not differentiated; in the single cavity 1; pendulous; hemianatropous to anatropous.

Fruit and seed features. Fruit fleshy; indehiscent; a drupe; 1 celled; 1 seeded. Seeds endospermic. Endosperm oily, or not oily. Seeds without a testa. Cotyledons 2.

Etymology. From the Greek for "on the outside, outside of" and "fruit"; refers to the fleshy pedicel which resembles a fruit.

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.
  • Wheeler, J. R.; Rye, B. L.; Koch, B. L.; Wilson, A. J. G.; Western Australian Herbarium (1992). Flora of the Kimberley region. Western Australian Herbarium. Como, 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.