Annona L.

Scientific Description

Family Annonaceae.

Habit and leaf form. Trees (in Australia). ‘Normal’ plants. Leaves well developed. Plants with roots; unarmed; autotrophic. To 3–7 m high (in Australia). Self supporting. Mesophytic. Not heterophyllous. Leaves medium-sized; alternate; distichous (in Australia); with blades; leathery; petiolate; simple; not peltate; epulvinate. Leaf blades neither inverted nor twisted through 90 degrees; entire; flat; ovate, or oblong (in Australia); attenuate at the base (‘acute’ or ‘obtuse’). Mature leaf blades adaxially sparsely pubescent (on the nerves), or glabrous; abaxially sparsely pubescent (on the nerves), or glabrous. Leaves without stipules. Leaf blade margins entire; flat. Leaf anatomy. Hairs present, or absent.

Reproductive type, pollination. Fertile flowers hermaphrodite (in Australia). Unisexual flowers absent (in Australia). Plants hermaphrodite (in Australia). Plants homostylous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; axillary (‘extra-axillary or opposite the leaves’). Inflorescence few-flowered. Inflorescences simple; axillary (‘extra axillary’), or leaf-opposed. Flowers pedicellate; medium-sized; regular; not resupinate; 3 merous; cyclic; pentacyclic (in Australia). Perianth with distinct calyx and corolla; 9; 3 -whorled; isomerous. Calyx present; 3; 1 -whorled; gamosepalous. Calyx lobes markedly longer than the tube. Calyx valvate; regular. Corolla present; 6; 2 -whorled; polypetalous; valvate (in outer whorl), or imbricate (in inner whorl). Androecium present. Fertile stamens present. Androecial members indefinite in number. Androecium 100 (‘very numerous’). Androecial members free of one another; 1 -whorled. Stamens 100 (‘very numerous’); polystemonous; filantherous. Anthers separate from one another; dehiscing via longitudinal slits; tetrasporangiate. Fertile gynoecium present. Gynoecium 100 carpelled (‘numerous’). Carpels increased in number relative to the perianth. Gynoecium apocarpous; eu-apocarpous; partly inferior. Carpel stylate; apically stigmatic; 1 ovuled. Placentation basal.

Fruit and seed features. Fruit 50–120 mm long (in Australia). The fruiting carpel indehiscent. Dispersal unit the seed. Fruit 50 seeded (‘many’).

Geography, cytology, number of species. Adventive. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province. A genus of ca 110 species; 1 species in Western Australia; A. reticulata L.; 0 endemic to Western Australia.