Aralia L.

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

Distribution

A genus of approximately 40 species throughout North America and east Asia with several species in Malesia but only a single species reaching western New Guinea (Aralia bipinnata Blanco).

Recognition

The genus is quite variable, especially with regard to the vegetative morphology, and the description below is adapted to emphasise characters found in the New Guinea taxon. It can be recognised as being a small poorly branched tree with prickles throughout (on the stems, leaf rachis and inflorescence axis), the large, bipinnate leaves and the large terminal inflorescence with flowers with imbricate petals.

Morphology General Habit

Sparingly branched shrubs or small trees (to 7 m in New Guinea), rarely herbaceous, unarmed or prickly throughout (in New Guinea)

Morphology Leaves

Leaves pinnate to tripinnate (bipinnate to 1.5 m long in New Guinea), rachis swollen and articulated at the nodes, usually with leaflets at the insertion of the lateral pinnae, leaflets crenate to serrate; petiole with a sheathing base

Morphology Reproductive morphology Inflorescences

Inflorescences terminal, paniculate with branches ending in umbellules

Morphology Reproductive morphology Flowers

Flowers 5-merous, sessile or pedicellate with an articulation below the flower; calyx with 5 teeth; petals 5, imbricate; stamens 5; ovary (2–)5–6-celled; styles (2–)6, connate at the base or free (in New Guinea)

Morphology Reproductive morphology Fruits

Fruit a fleshy drupe; pyrenes cartilaginous, compressed, spherical when fresh and 5-angular when dry

Morphology Reproductive morphology Seeds

Seeds laterally compressed; endosperm uniform.

Ecology

In New Guinea, Aralia is found in the western part of the island from the Bird’s Head Peninsula to Tembagapura, in open forest and secondary habitats to c. 2500 m.