Australian Tropical Rainforest Plants - Online edition

Denhamia bilocularis (F.Muell.) M.P.Simmons


Shrub (woody or herbaceous, 1-6 m tall)
Tree
Click/tap on images to enlarge
Leaves and fruit. © CSIRO
Shoot with inflorescence [not vouchered]. CC-BY: S. & A. Pearson.
Cotyledon stage, epigeal germination. © CSIRO
10th leaf stage. © CSIRO
Family

McKenna, M.J., Simmons, M.P., Bacon, C.D. & Lombardi, J.A. (2011) Systematic Botany 36(4): 929.

Common name

Orangebark

Stem

Shrub or small tree to 10 m tall. Inner bark orange or orange-brown. Stems hairless with fine longitudinal ridges.

Leaves

New growth often reddish, twig bark orange when scraped gently with a knife. Leaves simple, alternate. Stipules 2, free, lanceolate, usually 0.5-2 mm long. Petiole 2-7 mm long, articulation visible where petiole attaches to stem. Leaf blade elliptic to narrow-elliptic, oblong, 3-11 cm long, 1.5-7 cm wide, base cuneate or attenuate, margins toothed, apex acute, acuminate or rarely obtuse. Lateral veins 5-8 pairs. Surfaces hairless. Midrib raised on the upper surface. Lateral veins forming loops inside the blade margin. Twigs angled or longitudinally ribbed.

Flowers

Inflorescence axillary, racemose. Pedicels 1.8-2.5 mm long. Flowers bisexual, actinomorphic, 4 or 5 merous. Sepals ± free, broadly ovate, c. 0.8 mm long. Petals free, oblong-ovate, 1.5-2.5 mm long, white to cream. Stamens inserted beneath disc, alternating with petals, anther filaments about 0.8-2 mm long, anthers globose, small. Disc prominent, about 1.2 mm diam.; ovary superior, 2(-4) locular; style elongate, stigma ± 2-lobed.

Fruit

Fruit a capsule, 2 valved, globular or obovoid, ellipsoid or obcordate, 5-8 mm long, 4-7 mm diam., style persistent at apex, yellow. Seeds 1 or 2, black or brown, ellipsoid, 4 x 3 mm; aril thinly fleshy, smooth, orange, completely or partly covering seed. Embryo green. Cotyledons about 2.5 x 2 mm, radicle about 0.6 mm long.

Seedlings

Seed germination time 45 days. Seedling glabrous. Cotyledons elliptical, about 13 x 7-9 mm. Hypocotyl 4-angled, square in transverse section. First leaves oblanceolate, apex mucronate, base attenuate.  Leaf blade margins toothed with 3-7 teeth on each side particularly towards the apex. Midrib raised on the upper surface. At the tenth leaf stage: leaf  blades elliptic, apex apiculate, base attenuate, margins with 10-16 serrate teeth on each side. Midrib raised on the upper surface. Stipules lanceolate, about 1 mm long, base lacinate with an extension or lobe pointing backwards. Stems 4-5-angled with lines running down from the decurrent leaf bases. Roots orange.

Distribution and Ecology

Occurs in NEQ, CEQ, and southwards to north eastern NSW. Grows in dry rainforest, vine thickets and open forest.

Natural History & Notes

This profile information and associated coding has been adapted from Hyland (2010); Cooper & Cooper (2004), McKenna et al. (2011), Simmons (2004) and Harden et al. (2014).

Synonyms

Maytenus bilocularis (F.Muell.) Loes., Die Naturlichen Pflanzenfamilien Edn. 2, 20 b: 135 (1942).  Celastrus bilocularis F.Muell., Transactions of the Philosophical Institute of Victoria 3: 31 (1859), Type: "On the shrubby banks of the rivers Dawson and Burnett.".  Maytenus sp. Windsor Tableland (B.Hyland 3416RFK).

RFK Code
1028
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