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Balanopaceae


This is a very small family, with a few species in Australia, New Caledonia and Fiji. One or two species of Balanops (the only genus in the family) occur in rain forests in north-east Queensland.

Characteristic features of the family Balanopaceae in Australia include:

  • rain forest trees or shrubs with elliptic, oblong or obovate, alternate leaves
  • plants dioecious (with male and female flowers borne on different plants)
  • flowers in leaf axils, female flowers solitary, male flowers in catkins, lacking a perianth but subtended by one (in males) or numerous (in females) scales
  • fruit acorn-like

Description

Evergreen trees or shrubs. Internal secretions not obvious. Plants glabrous or with simple, non-glandular, unicellular hairs. Leaves alternate and spiral, petiolate. Stipules present or absent. Lamina simple, symmetric, elliptic, oblanceolate or obovate; base cuneate or rarely attenuate; margins entire or obscurely crenate, revolute or recurved; one-veined, or the venation pinnate, with the midrib conspicuous, and the tertiary venation not reticulate; surfaces not punctate; leathery. Male and female flowers occurring on separate plants. Inflorescences terminal, axillary, cauliflorous or ramiflorous, consisting of catkins or solitary flowers. Bracts and bracteoles present. Pollination by wind. Flowers odourless; sessile. Floral disc absent; nectaries absent. Perianth vestigial or absent. Fertile stamens 110 (12), free of the ovary and style, distinct from each other, all ±equal. Staminal filaments apparently absent. Anthers basifixed, not versatile, opening sideways by longitudinal slits; 2-celled. Ovary superior and sessile. Carpels 2, fused; ovary with 12 locules. Style terminal, single and 2-branched above or from the base, penicillate. Ovules 1 per locule, sessile; placentation basal. Fruit dry or fleshy, an indehiscent nut. Disseminule micro-surface ±smooth, orange, dull. Seeds 12 per fruit. Aril absent. Cotyledons 2. Embryo straight.
(Note: this description has been generated from the coded data compiled for the key. Any errors in the key data will be reflected in the descriptions.)

A treatment of the family Balanopaceae has been published in:
Flora of Australia 3: 93-95.

Australian genera of Balanopaceae (as recognised for the Flora of Australia)

Balanops


Balanops australiana (fruits)
Photo: S.Pearson S.Pearson