Atractocarpus Schltr. & K.Krause

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

A genus of 29 species distributed in the Philippines, New Guinea and the Solomon Islands and from northern Australia to the Pacific; four species occur New Guinea (three endemics). The genus now includes Trukia Kaneh. and some species transferred from Gardenia J.Ellis (see Puttock 1999).

Morphology General Habit

Shrubs or small trees to 15 m (rarely epiphytic scandent shrubs); bark sometimes papery and flaking; unarmed. Raphides absent

Morphology Leaves Stipules

Stipules triangular, sheathing or not, sometimes large, prominent ridges present or absent, eventually caducous

Morphology Leaves

Leaves sometimes ternate or 4-nate, occasionally anisophyllous, domatia present or absent. Inflorescences terminal, overtopped (pseudo-axillary) or terminal on lateral branches with reduced leaves, (1–)3–many-flowered dichasial cymes or thyrses. Flowers bisexual or dimorphic and functionally unisexual, plants dioecious or gynodioecious, 5-merous, often fragrant; calyx cylindrical, lobes triangular, linear or spathulate or absent, usually persistent; corolla overlapping to the left in bud, white or cream to light yellow, sometimes hairy on outside, tube strongly to weakly urceolate, lobes ±equal or longer than tube; anthers sessile to subsessile, included, sterile anthers shorter; style included, stigma club-shaped, bi-lobed, lobes connate; ovary 2-locular, ovules many per locule, placentation axile

Morphology Reproductive morphology Fruits

Fruit a fleshy berry or drupe, globular or narrowing at base and apex, often green maturing to orange or red, surface often rough and mealy

Morphology Reproductive morphology Seeds

Seeds few to numerous, laterally compressed, embedded in placental tissue.

Ecology

The genus grows in a variety of habitats including dense primary lowland rain forest, on forest margins, in vine forests and thickets sometimes on swampy ground or on clay overlying limestone.

Recognition

Atractocarpus can be distinguished from Gardenia by its included stamens and styles. Some taxa in the region have very large stipules with three prominent ridges converging at the apex. The inflorescence axis often dries dark but may become straggly and straw-like with age. There are also some similarities to Timonius which has axillary inflorescences and Aidia which flowers at alternate nodes and has smaller fruits.