Alphitonia Endl.
Gen.Pl. 1098 (1838)

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

Scientific Description
B. Richardson, Thursday 8 September 2016

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.

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.