Hancea Seem.

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

Distribution

A small genus of c. 18 species from Madagascar (subgen. Cordemoya) and southern China and through Malesia (subgen. Hancea). Species of Hancea were previously treated in Mallotus, but pollen and leaf anatomical characters distinguish the two (see below). Two species are found in New Guinea: Hancea papuana (J.J.Sm.) S.E.C.Sierra, Kulju & Welzen from the environs of Jayapura, and H. penangensis (Müll.Arg.) S.E.C.Sierra, Kulju & Welzen scattered throughout New Guinea (though poorly known from Indonesian New Guinea).

Morphology General Habit

Small trees to 15(–25) m; branches with slender or conspicuously swollen nodes Plants monoecious and/or dioecious

Morphology General Indumentum

Indumentum composed of simple hairs and sometimes capitate glandular hairs with multicellular stalks

Morphology General

Latex absent. Stipules axillary or interpetiolar

Morphology Leaves

Leaves simple, opposite and strongly unequal in size (leaves appearing like stipules); non-reduced leaves with entire or wavy margins, venation pinnate (in New Guinea)

Morphology Reproductive morphology Inflorescences

Inflorescences ramiflorous, axillary, or terminal-Flowers actinomorphic; sepals persistent; petals and disk absent

Morphology Reproductive morphology Flowers

Staminate flowers: sepals 3–4, valvate, free to basally connate; stamens numerous (up to c. 100), thecae 2, parallel, opening extrorsely and lengthwise; pistillode absent

Morphology Reproductive morphology Flowers Gynoecium Pistil

Pistillate flowers: sepals 4–5, valvate or imbricate, free; staminodes rarely present; style short, stigmas erect, inner surface densely covered with short papillae, outer surface hairy

Morphology Reproductive morphology Fruits

Fruits dehiscent capsules, opening loculicidally-septicidally or septicidally-loculicidally, spiny, spines sometimes with terminal glands

Morphology Reproductive morphology Seeds

Seeds (sub)globose, somewhat trigonous in transverse section; caruncle or aril absent.

Ecology

Hancea are usually found in the understorey of primary forests where they can be common, but are also found in secondary/disturbed habitats including scrub, river banks and roadsides understorey; to c. 1650 m.

Recognition

Hancea species are very similar in appearance to Mallotus, but technically differ in the morphology of the hairs: Hancea species in New Guinea have capitate glandular hairs with multicellular stalks, while Mallotus is recognised by the presence of spherical to disc-shaped multicellular glandular hairs. Both H. papuana and H. penangensis have opposite leaves but one of each pair is ‘stipuliform’, i.e. appearing like a stipule; note that the true stipules of both species are early caducous.