Elaeodendron Jacq.

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

Distribution

This genus has traditionally been included within Cassine (e.g. see Fl. Males., and Kostermans in Gard. Bull. Sing. 39: 177–191, 1986). Cassine has recently been more narrowly defined to include species in southern Africa (e.g. see Archer & Van Wyk in S. Afr. J. Bot. 63: 146–157, 1997). A single species is found in the Lesser Sunda Islands and reaches the Kei Islands (Elaeodendron glaucum (Rottb.) Pers.), and another species is found in Queensland (E. melanocarpum F.Muell.), and the genus is included here as it may be found in the southern areas of New Guinea.

Morphology General Habit

Shrubs or trees to 25 m

Morphology Leaves Stipules

Stipules small, caducous

Morphology Leaves

Leaves usually decussate (in New Guinea), subopposite or alternate, margins entire to dentate

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, cymose

Morphology Reproductive morphology Flowers

Flowers bisexual (in New Guinea) or unisexual (plants dioecious, polygamous or monoecious), 4–5-merous; calyx lobes imbricate; petals imbricate; stamens inserted inserted on the outer margins of the disk, anthers longitudinally dehiscent, introrse or extrorse; disk fleshy, annular, entire, 4–5-angled, or lobed, intrastaminal or stamens inserted on disk; ovary 2–4-locular, the base sometimes united with the disk; ovules 2 per locule, erect

Morphology Reproductive morphology Fruits

Fruit a drupe, spheroid or ellipsoid, fleshy or coriaceous, 1–2 celled

Morphology Reproductive morphology Seeds

Seeds 1–2, ellipsoid, or ovoid, flattened or triangular, aril lacking.

Ecology

The two species are both found in lowland monsoon forest in Queensland and the Lesser Sunda Islands (Java, Timor, Kei Islands) below 300 m, and if present in mainland New Guinea, is most likely to occur in the southern monsoon habitats.

Recognition

The genus can be recognised by the decussate leaves (rarely with some alternate leaves), the 4–5-merous flowers with free petals and 4–5 stamens, and the 2-celled ovary, and the drupaceous fruit, which usually has a single seed lacking an aril.

Celastraceae, N.K.B. Robson, N. Hallé, B. Mathew and R. Blakelock†. Flora of Tropical East Africa. 1994

Morphology General Habit

Trees or shrubs, without latex, glabrous; branches terete to lined, unarmed, not forming short shoots

Morphology Leaves

Leaves all opposite or subopposite to alternate towards the base of the shoot, rarely heteromorphic, petiolate; stipules free, small, caducous

Morphology Reproductive morphology Inflorescences

Inflorescence pedunculate to sessile, regularly dichasial, few–many-flowered, single or on specialised shoots forming “panicles” in axils of foliage leaves or prophylls; bracts persistent

Morphology Reproductive morphology Flowers

Flowers bisexual or unisexual, sometimes polygamous or dioecious, with or without staminodes and well-developed pistillodes, pedicellate, with pedicels articulated at or above the base

Morphology Reproductive morphology Flowers Calyx

Sepals 4–5, unequal or equal, imbricate, united at the base, with margin entire or rarely finely serrulate

Morphology Reproductive morphology Flowers Corolla

Petals 4–5, green to white or yellow, imbricate in bud, spreading

Morphology Reproductive morphology Flowers Disc

Disc intrastaminal, single, thick, convex to concave, entire or shallowly 4–5-angled or -lobed

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4–5, with filaments thin, united with the base of the disc; anthers versatile, introrse, with separate thecae dehiscing longitudinally

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary superior, sessile, ± deeply immersed in the disc, 2–3(–?4)-locular, with (1–)2 erect collateral ovules in each locule; style short, pyramidal, simple; stigma small, entire or slightly 2–3-lobed

Morphology Reproductive morphology Fruits

Fruit drupaceous, hard or ± fleshy

Morphology Reproductive morphology Seeds

Seeds 1–2(–3), exarillate, not winged, without endosperm.

Celastraceae, N. K. Robson. Flora Zambesiaca 2:2. 1966

Morphology General Habit

Trees or shrubs, without latex, glabrous.

Morphology Leaves

Leaves all opposite, or subopposite to alternate on young shoots, rarely heteromorphic, petiolate; stipules free, small, caducous.

Morphology Reproductive morphology Inflorescences

Inflorescence pedunculate to sessile, regularly dichasial, simple or borne on specialised shoots forming “panicles” in axil of foliage leaves or prophylls; bracts persistent.

Morphology Reproductive morphology Flowers

Flowers bisexual or unisexual, sometimes dioecious, pedicellate.

Morphology Reproductive morphology Flowers Calyx

Sepals 4–5, imbricate, united at the base, with margin entire or rarely finely serrulate.

Morphology Reproductive morphology Flowers Corolla

Petals 4–5, green to white or yellow, imbricate in bud, spreading.

Morphology Reproductive morphology Flowers Disc

Disk intrastaminal, single, convex to flat, thick, entire or shallowly 4–5-lobed.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4–5, with filaments thin, united with base of disk; anthers versatile, introrse, with separate thecae dehiscing longitudinally.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary superior, sessile, ± immersed in disk, 2–3-locular, with (1)2 erect collateral ovules in each loculus; style short, pyramidal, simple; stigma small, entire or slightly 2–3-lobed.

Morphology Reproductive morphology Fruits

Fruit drupaceous, hard or ± fleshy.

Morphology Reproductive morphology Seeds

Seeds 1–2(3), exarillate, with endosperm.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Trees or shrubs, unarmed, without latex, glabrous

Morphology Leaves

Leaves all opposite or sometimes alternate towards base of shoot

Morphology Reproductive morphology Inflorescences

Inflorescences axillary pedunculate to sessile regularly dichasial simple cymes, sometimes aggregated into pseudo-panicles Flowers bisexual or unisexual, plant sometimes dioecious

Morphology Reproductive morphology Flowers Calyx

Sepals 5, imbricate

Morphology Reproductive morphology Flowers Corolla

Petals 4–5, green to white or yellow, imbricate in bud

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 4–5; filaments slender, united with base of disk

Morphology Reproductive morphology Flowers Disc

Disk intrastaminal, single, thick, convex to concave, shallowly 4–5-lobed to entire

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary sessile, deeply immersed in disk, 2–3-celled, with (1–)2 ovules in each cell; style simple with entire or 2–3-lobed stigma

Morphology Reproductive morphology Fruits

Fruit a drupe, hard or fleshy

Morphology Reproductive morphology Seeds

Seeds 1–2(–3), without arils or wings.

Distribution

About 38 species in the Old World tropics, South Africa, the West Indies and Central America.

Celastraceae, N. K. Robson. Flora Zambesiaca 2:2. 1966

Morphology General Habit

Trees or shrubs, without latex, glabrous; branches striate or angular.

Morphology Leaves

Leaves opposite on flowering shoots, spiral or alternate on young shoots, sometimes heteromorphic, petiolate; stipules, free, small, deciduous.

Morphology Reproductive morphology Inflorescences

Inflorescence pedunculate, regularly dichasial, simple, in axil of foliage leaves; bracts persistent.

Morphology Reproductive morphology Flowers

Flowers bisexual, pedicellate, with whorls all isomerous.

Morphology Reproductive morphology Flowers Calyx

Sepals 3–4, imbricate, free, with margin entire.

Morphology Reproductive morphology Flowers Corolla

Petals 3–4; green, imbricate in bud, spreading.

Morphology Reproductive morphology Flowers Disc

Disk extrastaminal or almost so, single, convex, thick, entire.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 3–4, with filaments thin, united with disk; anthers versatile, introrse, persistent, with separate thecae dehiscing longitudinally.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary superior, sessile, ± immersed in disk, 3–4-locular, with 2 erect collateral ovules in each loculus; style short, cylindric or pyramidal, simple; stigma small, entire or slightly 3–4-lobed.

Morphology Reproductive morphology Fruits

Fruit drupaceous, hard or ± fleshy.

Morphology Reproductive morphology Seeds

Seeds solitary, exarillate, with endosperm.