Flora of the Hawaiian Islands
Dicotyledon Literature for Trema orientalis
Florence, 1997; Soepadmo, 1977; Wagner et al., 1990, 1999; Lorence & Wagner, 2020.
   Cannabaceae -- The Elm, Hemp Family Bibliography
      Trema orientalis

Common name(s): charcoal tree, gunpowder tree
General Information
DistributionNative to tropical Africa, Madagascar, SE Asia, Japan, Malesia, Australia (Queensland), Melanesia, Micronesia, and Polynesia.In the Hawaiian Islands, naturalized on Kaua`i, O`ahu, Moloka`i, Lana`i, Maui, Hawai`i.

Cannabaceae - Trema orientalis Cannabaceae - Trema orientalis

Tree, 3‒36 m tall, trunk becoming more or less buttressed; branchlets densely pubescent with appressed to erect, silvery, glaucous, or grayish hairs and short, multicellular, glandular hairs.
Leaves distichous, petiolate; blade ovate to narrowly elliptic or lanceolate, 6‒19 cm long, 1.5‒7(‒10) cm wide, thin to thick, coriaceous, often rigid and brittle, adaxial surface sparsely to strongly scabrid with pustulate-based hairs, abaxial surface strigose or densely tomentose with silvery, appressed, unicellular hairs and shorter, multicellular, glandular hairs, margin serrate to denticulate, apex acute to acuminate-caudate, base asymmetrical, cordate, rounded, or occasionally truncate; petiole 0.7‒1.8 cm long; stipules linear-lanceolate, ca. 5‒7 mm long.
Flowers of different sexes borne on separate branches in a branched panicle or thyrse; bracts ovate, 2‒3 mm long, sepals 5; staminate flowers 20‒100, in inflorescences to 2.5‒5 cm long, sepals ca. 1.5‒2 mm long, pistillode present; pistillate flowers 5‒15, in inflorescences 1‒2.5 cm long, sepals ca. 1‒1.5 mm long, staminodes absent.
Fruit red-orange to black at maturity, 3‒5 mm long and wide, 1-seeded.
Seed ovoid, to 1.8 mm long, 1.6 mm wide, 1 mm thick.
In the treatment of Trema for Flora Malesiana, Soepadmo (1977) placed a number of Pacific Island taxa in synonymy under Trema orientalis, recognizing three species in the Pacific region: T. cannabina, T. orientalis, and T. tomentosa. Although Florence (1997a) recognized T. discolor (Brongn.) Blume as a French Polynesian endemic, Soepadmo (1977) included it as a synonym of T. orientalis. The collections of Trema from Ua Pou have relatively sparse, strigose pubescence on the abaxial blade surface with the epidermis clearly visible and thus correspond to T. tomentosa sensu Soepadmo. However, Wagner et al. (1999, pp. 1296–1297) discussed the possible differences between T. orientalis and T. tomentosa and concluded that "since these entities are exceedingly similar and may represent forms of one species, we have treated them together here using the older name, T. orientalis." We adopt this same concept for the Marquesas material.
David Lorence