Australian Tropical Rainforest Plants - Online edition

Syzygium armstrongii (Benth.) B.Hyland

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10th leaf stage. © CSIRO
Scale bar 10mm. © CSIRO

Hyland, B.P.M. (1983) Australian Journal of Botany Supplementary Series 9: 54.


Sections of bark included in the wood.


Oil dots variable, usually rather sparse but sometimes quite numerous. Leaf blades about 5.5-14.5 x 1.7-4 cm. Midrib grooved or shallowly channelled towards the base on the upper surface. Lateral veins about 12-25 on each side of the midrib. Twigs pale, bark finely flaky.


Bracts sometimes present at anthesis, subulate, about 0.8-1.1 mm long. Flowers conspicuously pedicellate, calyx tube (hypanthium) + pedicel about 4-7.5 mm long, calyx tube (hypanthium) about 2-4 mm diam., calyx lobes dimorphic, rounded, larger lobes about 1-1.5 mm long. Petals orbicular, about 4 mm diam., oil dots numerous, conspicuous, more than 30 per petal. Outer staminal filaments about 3-7 mm long, anthers about 0.5 x 0.5 mm, gland terminal, near the back of the anther. Ovules about 5-9 per locule, placentas axile, central, ovules radiating, ascending. Style about 5.5-9.5 mm long, equal to or exceeding the stamens.


Fruits depressed globular, wider than long, attaining about 15 x 22 mm, surface conspicuously rugose, pericarp succulent-spongy, containing many large oil glands, particularly near the epidermis, calyx lobes persistent, inconspicuous, about 1 mm long. Seed solitary, about 8-10 x 12-14 mm, testa attached to the pericarp but much more strongly attached to the outer surface of the cotyledons by short, dark, tanniferous, root-like protrusions, cotyledons uniformly textured except for the peripheral layer. Radicle basal, cotyledonary stipules present.


Cataphylls about 4 pairs. Cotyledons distinctly petiolate. At the tenth leaf stage: leaf blade elliptic, apex acuminate, base cuneate or attenuate, glabrous; oil dots sparse, large, often visible to the naked eye; stems somewhat flattened at the nodes.

Distribution and Ecology

Endemic to NT. Altitudinal range from sea level to 200 m. Usually grows as a rheophyte in gallery forest along creeks and rivers.

Natural History & Notes

Cultivated to a small degree around Darwin where it makes a fine shady street tree or for parks and gardens.

Wood specific gravity 0.67. Hyland (1983).

Eugenia armstrongii Benth., Fl. Austr. 3: 286(1867), Type: Port Essington, Armstrong 621; lecto: K.
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