Allamanda L.

Scientific Description

Family Apocynaceae.

Habit and leaf form. Perennial scandent or scrambling shrubs, or trees (not in Australia); evergreen; laticiferous (white). Plants unarmed. Leaves cauline. To 2–6 m high (in shrubs). Mesophytic. Not heterophyllous. Leaves medium-sized; opposite, or whorled; 3–5 per whorl; ‘herbaceous’ to leathery; petiolate; simple. Leaf blades dorsiventral; entire; ovate, or obovate, or elliptic; pinnately veined; cuneate at the base. Mature leaf blades adaxially glabrous, or pubescent (with scattered basifixed hairs); abaxially glabrous, or pubescent (with scattered basifixed hairs). Leaves without stipules. Leaf blade margins entire. Leaf anatomy. Hairs present; glandular hairs absent. Unicellular hairs absent. Complex hairs present. Branched hairs absent. Complex hairs peltate.

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

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in cymes. Inflorescences compound; extra- axillary, or terminal. Flowers pedicellate; bracteate; large; regular; 5 merous; tetracyclic. Hypogynous disk present; of separate members (cupuliform, 5-lobed or subentire). Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; lobed (lobes are deeply divided); lobulate. Calyx lobes markedly longer than the tube. Calyx erect; hairy; exceeded by the corolla; regular; green. Calyx lobes ovate. Corolla present; 5; 1 -whorled; appendiculate (with corolline corona); gamopetalous; lobed; lobulate. Corolla lobes about the same length as the tube. Corolla contorted (sinistrorse in bud); campanulate to funnel-shaped; regular; hairy abaxially (surmounted by tufts of hair); hairy adaxially (surmounted by tufts of hair); plain; yellow, or purple. Corolla lobes obovate. Androecial members definite in number. Androecium 5. Androecial members adnate (epipetalous); united with the gynoecium (anthers adherent to style-head); all equal; 1 -whorled. Stamens 5 (concealed by scales). Staminal insertion midway down the corolla tube to in the throat of the corolla tube (i.e. in the upper part of the tube). Stamens all inserted at the same level; remaining included; all more or less similar in shape; isomerous with the perianth; oppositisepalous; all alternating with the corolla members. Anthers all alike; dehiscing via longitudinal slits; appendaged; apiculate. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium stylate. Styles 1. Stigmas 1. Placentation axile.

Fruit and seed features. Fruit non-fleshy; a schizocarp. Mericarps comprising follicles (1,with long soft spines). Dispersal unit the seed. Fruit 2–4 seeded. Seeds compressed (ellipsoidal); not conspicuously hairy; wingless.

Geography, cytology, number of species. World distribution: tropical America. Adventive. Australian states and territories: Western Australia and Queensland. Northern Botanical Province (Koolan Island). A genus of 12–15 species; 1 species in Western Australia.

Additional comments. Etymology: named for Frederic Allamand (b. 1736), Swiss botanist and physician, a correspondent of Linnaeus.

Etymology. After Fre'de'ric Allamand (b.1736), Swiss botanist and physician, a correspondent of Linnaeus.