Australian Tropical Rainforest Plants - Online edition

Pilidiostigma tetramerum L.S.Sm.

Herb (herbaceous or woody, under 1 m tall)
Shrub (woody or herbaceous, 1-6 m tall)
Click/tap on images to enlarge
Flower. © Barry Jago
Flowers [not vouchered]. © G. Sankowsky
Flowers [not vouchered]. © G. Sankowsky
leaf and flowers [not vouchered]. © G. Sankowsky
Fruit, three views, cross section and seed. © W. T. Cooper
Scale bar 10mm. © CSIRO
Cotyledon stage, hypogeal germination. © CSIRO
10th leaf stage. © CSIRO

Smith, L.S. (1959) Proceedings of the Royal Society of Queensland 70: 30. Type: Queensland, Hugh Nelson Range, ca. 2 miles S. of the Crater, 20 Nov. 1958, L.S. Smith 10505; holo: BRI, Iso: A, BISH, CANB, K, NSW.


Occasionally recorded as a small tree but usually flowers and fruits as a shrub about 2-3 m tall.


Leaf blades about 7-8 x 2-2.5 cm. Venation difficult to discern. Two intramarginal veins visible on the leaf blade, the outer one less obvious, about 0.5-1 mm from the margin, the inner one about 2 mm from the margin. Petiole +/- transversely wrinkled, flattened or channelled on the upper surface. Oil dots quite numerous.


Calyx glabrous, lobes dimorphic, the larger two +/- petaloid. All calyx lobes marked by oil glands. Petals concave, +/- orbicular, about 2.5 mm diam., oil glands less obvious than those on the calyx lobes. Staminal disk flat-topped, stamens arranged in a single row with only occasional overlaps. Stigma terminal, peltate, significantly wider than the style.


Fruits depressed globular, about 15 mm diam., +/- triangular in transverse section, calyx lobes persistent at the apex. Seeds angular, about 7-8 mm diam., cotyledons fused together, the radicle transversely oriented in the seed. Testa +/- smooth.


Cataphylls about 2 or 3 pairs, produced between the cotyledons and the first pair of true leaves. At the tenth leaf stage: leaf blade elliptic, apex acute, base cuneate or attenuate, oil dots visible with a lens. Leaf venation difficult to discern. Stipules caducous, small and inconspicuous. Stem glabrous, 4-angled or winged. Seed germination time 134 to 191 days.

Distribution and Ecology

Endemic to NEQ. Altitudinal range from near sea level to 1200 m. Grows as an understory plant in undisturbed lowland, upland and mountain rain forest.

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