Australian Tropical Rainforest Plants - Online edition

Xanthostemon youngii C.T.White & W.D.Francis


Shrub (woody or herbaceous, 1-6 m tall)
Tree
Click/tap on images to enlarge
Flowers. © G. Sankowsky
Leaves and Flowers. © CSIRO
Leaves and Flowers. © CSIRO
Scale bar 10mm. © CSIRO
Cotyledon stage, epigeal germination. © CSIRO
10th leaf stage. © CSIRO
Trunk. © G. Sankowsky
Family

White, C.T. & Francis, W.D. (1926) Proceedings of the Royal Society of Queensland 37: 159. Type: Qld, Temple Bay, Cape York Peninsula, July 1923, J.E.Young; holo: BRI.

Common name

Penda, Crimson; Penda, Red; Crimson Penda; Red Penda

Stem

Usually grows into a tree but in windswept situations flowers and fruits as a shrub. Cream or pale brown stripes in both the inner and outer blazes.

Leaves

Oil dots visible with a lens, about 1-4 oil dots per reticulation, frequently one, sometimes many reticulations are found without an enclosed oil dot. Leaf blades about 3.5-7 x 1.5-3.5 cm, margins recurved. Lateral veins curving inside the blade margin sometimes forming loops. Terminal buds, young leaf-bearing twigs and new leaves clothed in pale, prostrate hairs. Young leaves bright red.

Flowers

Calyx tube (hypanthium) glabrous, about 4 x 15 mm, divided into five saccate, nectariferous lobes. Calyx lobes glabrous or puberulent, about 3-4 mm long. Petals pubescent, broadly spathulate, about 9-10 x 7 mm. Stamens +/- arranged in bundles of about 14 or 15 opposite each calyx lobe nectary. Staminal filaments red, pubescent towards the base, about 20-25 mm long, each inserted in an orifice in the base of the anther, anthers about 2 mm long, terminal gland +/- apiculate. Pollen white. Ovary hirsute, about 5-5.5 mm diam., projecting above the calyx tube (hypanthium), placentas peltate. Style red, pubescent towards the base, about 17-20 mm long. Stigma small and terminal.

Fruit

Fruits +/- globular, about 15 mm diam. (excluding the persistent calyx at the base). Seeds flat, about 5 mm long. Embryo +/- orbicular, about 4 mm long. Radicle curved.

Seedlings

Cotyledons orbicular, about 6-9 mm diam. First pair of leaves elliptic, both the upper and lower surfaces hairy. Stem clothed in long erect hairs. At the tenth leaf stage: leaf blade elliptic to obovate, about 25 x 15 mm, apex acute to apiculate, base cuneate. Oil dots large and numerous. Petiole about 2.5 mm long. Stipules filiform, about 0.5 mm long. Stem, petiole and both the upper and lower surfaces of the leaf blade clothed in simple, erect, fine hairs. Seed germination time 50 days.

Distribution and Ecology

Endemic to Queensland, occurs in CYP. Altitudinal range quite small, from near sea level to 30 m. Grows in beach forest on sand dunes.

Natural History & Notes

A spectacular tree that produces large bunches of bright red flowers. It is unfortunate that it is difficult to grow except in deep sand.

RFK Code
680
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