Ichnocarpus R.Br.

Scientific Description

Family Apocynaceae.

Habit and leaf form. Lianas, or shrubs (not in Australia); evergreen; laticiferous (white). Plants unarmed. Leaves cauline. Climbing, or epiphytic, or self supporting (not in Australia); scrambling. Mesophytic. Not heterophyllous. Leaves medium-sized; opposite; leathery, or membranous; petiolate (petioles connected by a straight rim around the stem), or subsessile; simple. Leaf blades dorsiventral; entire (or rarely sinuate); ovate, or obovate, or elliptic, or orbicular (i.e. ovate, ovate-elliptic, elliptic or elliptic-obovate); pinnately veined; cuneate at the base. Mature leaf blades adaxially glabrous, or pubescent (with basifixed hairs); abaxially glabrous, or pubescent (with 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, or in panicles. Inflorescences compound; terminal, or axillary; an elongate panicle of small dichasially branched, sessile or short pedunculate cymes. Flowers pedicellate; bracteate; small; fragrant, or odourless; regular; 5 merous; tetracyclic. Hypogynous disk present; of separate members (5-lobed), or annular. 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. Calyx lobes ovate, or triangular. Corolla present; 5; 1 -whorled; gamopetalous; lobed; lobulate. Corolla lobes about the same length as the tube, or markedly longer than the tube. Corolla contorted (dextrorse in bud); hypocrateriform (tube slightly constricted about the stamens and slightly narrower above); regular; hairy abaxially (scattered indumentum towards top), or glabrous abaxially; hairy adaxially (scattered indumentum towards top), or glabrous adaxially; plain; cream. Corolla lobes ovate. Androecial members definite in number. Androecium 5. Androecial members adnate (epipetalous); united with the gynoecium (i.e. stamens adherent to the style-head); all equal; 1 -whorled. Stamens 5. Staminal insertion near the base of the corolla tube, or midway down the corolla tube, or in the throat of the corolla 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. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous (the carpels united only by their styles); eu-syncarpous; superior (adnate to the base of the disc). Ovary plurilocular; 2 locular. Ovary summit hairy, the hairs not confined to radiating bands, or glabrous (rarely). Gynoecium stylate. Styles 1; hairy, or hairless (rarely). Stigmas 1. Placentation axile. Ovules 30–50 per locule (i.e. ‘many’ in 3 or 4 rows).

Fruit and seed features. Fruit 50–250 mm long; non-fleshy; a schizocarp. Mericarps comprising follicles (2). Dispersal unit the seed. Fruit 30–50 seeded (‘many’). Seeds compressed (linear to linear-oblong); small, or medium sized; conspicuously hairy; with a tuft of hairs (brown hairs at micropylar end); wingless.

Geography, cytology, number of species. World distribution: China, western Himalayas, Sri Lanka, Asia, Malesia (including Papuasia), and northern Australia. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, Northern Territory, and Queensland. Northern Botanical Province. A genus of c. 12 species; 1 species in Western Australia; 0 endemic to Western Australia.

Additional comments. Etymology: from the Greek ichnos (a vestige) and karpos (fruit), alluding to the follicles.

Etymology. From the Greek "a vestige" and "fruit", alluding to the slender follicles.