Alphitonia Endl.

Reference
Gen.Pl. 1098 (1838)
Name Status
Current

Scientific Description

Common name. Red Ash. Family Rhamnaceae.

Habit and leaf form. Trees, or shrubs. ‘Normal’ plants. Leaves well developed. Plants with roots; non-succulent; unarmed; autotrophic. To 20 m high (in Australia). Self supporting. Not heterophyllous. Leaves medium-sized; not fasciculate; alternate; with blades; petiolate, or subsessile; with ‘normal’ orientation; simple; not peltate. Leaf blades entire; elliptic; pinnately veined. Mature leaf blades adaxially glabrous, or pilose, or pubescent; abaxially glabrous, or pilose, or pubescent. Leaves with stipules. Stipules scaly. Leaf blade margins entire; flat. Leaf anatomy. Hairs present (densely pilose, ferruginous).

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

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in racemes. Inflorescences compound. The terminal inflorescence unit cymose. Inflorescences axillary. Flowers shortly pedicellate; minute; regular; 5 merous; cyclic; tetracyclic. Free hypanthium present. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed; hairy (outside), or glabrous; valvate; regular. Calyx lobes ovate to triangular. Epicalyx absent. Corolla present; 5; 1 -whorled; alternating with the calyx; polypetalous; regular; glabrous abaxially; glabrous adaxially; white to cream. Petals hooded. Androecium present. Fertile stamens present. Androecial members definite in number. Androecium 5. Androecial members adnate (to the base of the sepals); free of the gynoecium; free of one another; 1 -whorled. Stamens 5; all more or less similar in shape; isomerous with the perianth; alternisepalous; filantherous. Anthers separate from one another; dehiscing via longitudinal slits; bilocular; tetrasporangiate. Fertile gynoecium present. Gynoecium 3 carpelled. The pistil 1 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious; inferior. Ovary plurilocular; 3 locular. Gynoecium stylate. Styles 1; apical. Stigmas 3 - lobed. Ovules 1 per locule (in WA); ascending; anatropous.

Fruit and seed features. Fruit aerial; 6–11 mm long; indehiscent; a drupe. Dispersal unit the seed, or the fruit. Seeds 1 per locule.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia, Northern Territory, Queensland, and New South Wales. Northern Botanical Province. A genus of ca 20 species; 1 species in Western Australia, or 2 species in Western Australia (possibly); 0 endemic to Western Australia.

Etymology. From the Greek for pearl-barley, as the seeds resemble pearl-barley.

B. Richardson, 8 September 2016

Taxonomic Literature

  • 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.