Van-royena

Van-royena is a genus of the plant family Sapotaceae described as a genus in 1963.

There is only one known species, Van-royena castanosperma, which is endemic to the Cook region in northern Queensland. It grows at elevations of 0 - 1200 m above sea level, in rainforests.

Description
It is a tree that can grow up to 30 m tall, with a stem that's bark exudates (fluid emitted by an organism through pores or a wound) quite conspicuous. The narrow, yellowish, vertical stripes in the blaze shaded bark layer is thin, about 2-3 mm. It has simple leaves, that are 40 - 110 mm long and 15 - 50 mm wide. The petioles (leaf stalks) and twigs produce a milky exudate. It has a corolla (the collective term for the petals) is about 7 - 12 mm long, usually glabrous (lacking surface ornamentation) on both surfaces but the margins of the lobes are minutely ciliate (has small hairs). The stamens are attached well below the throat of the flower tube. The staminodes (sterile stamen) are subulate, about 2 mm long. The ovary is about 1.5 - 2.5 mm in diam., densely ferruginously (ruddy or rust-colored) and villous (covered with long, soft, straight hairs). The style is about 7.5 - 11 mm long. Between October and February, it produces ovoid shaped fruit (or seed capsules), which are 40 - 72 mm long and 30 - 40 mm wide. It has 1-3 seeds per fruit, which are 25 - 40 mm long and 25 - 30 mm wide. The testa (seed coat) is thick, hard and woody. The hilum (scar on a seed coat where it separates from its stalk) is 15 - 35 mm long and 12 mm wide.

Taxonomy
It has several common names including; milky plum, yellow plum, saffron boxwood and poison plum.

Under the Nature Conservation Act 1992 (NCA) of Australia, its status is least concern.

The genus name of Van-royena is in honour of Pieter van Royen (1923–2002), a Dutch botanist. He was an author of many papers on the flora of New Guinea. The Latin specific epithet of castanosperma refers to the evergreen tree of Castanospermum (in the family Fabaceae), also from Queensland.

Both the genus and the species were first described and published in Adansonia, n.s., Vol.3 on page 329 in 1963.

The genus is recognized by the United States Department of Agriculture and the Agricultural Research Service, but they do not list any known species.

Other sources

 * Swenson, U. et al. 2007. Phylogeny, diagnostic characters, and generic limitation of Australasian Chrysophylloideae (Sapotaceae, Ericales): evidence from ITS sequence data and morphology. Cladistics 23:201-228.