Family Ripogonaceae

Ripogonaceae Conran and Clifford

~ Smilacaceae

Habit and leaf form. Scandent shrubs, or lianas. With neither basal nor terminal aggregations of leaves. Climbing; scrambling (without the leaf tendrils of Smilacaceae sensu stricto). Leaves alternate, or opposite, or whorled; flat; leathery; petiolate, or subsessile; non-sheathing; without marked odour, or foetid (?); simple. Lamina entire; palmately veined (curved-convergent); cross-venulate.

Leaf anatomy. Vessels absent.

Stem anatomy. Secondary thickening absent. Xylem with vessels, or without vessels. Vessel end-walls scalariform.

Root anatomy. Root xylem with vessels.

Reproductive type, pollination. Fertile flowers hermaphrodite. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in racemes, or in spikes, or in panicles (rarely). Inflorescences axillary (usually), or terminal (rarely); axillary racemes or spikes, rarely terminal panicles; espatheate. Flowers regular; 3 merous; cyclic; pentacyclic. Perigone tube absent.

Perianth of ‘tepals’ (inconspicuous); 6; free; 2 whorled; isomerous; petaloid; similar in the two whorls.

Androecium 6. Androecial members free of the perianth; free of one another; 2 whorled. Androecium exclusively of fertile stamens. Stamens 6; isomerous with the perianth. Anthers basifixed; dehiscing via longitudinal slits; latrorse; bilocular; tetrasporangiate. Microsporogenesis successive. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; 1 aperturate; sulcate (reticulate).

Gynoecium 3 carpelled. Carpels isomerous with the perianth. The pistil 3 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 3 locular; sessile. Stigmas wet type. Placentation axile. Ovules 2 per locule; funicled; pendulous; anatropous.

Fruit fleshy; indehiscent; a berry. Seeds endospermic. Endosperm not oily (starchy). Seeds with starch. Embryo well differentiated (‘capitate’). Testa without phytomelan.

Physiology, biochemistry. Saponins/sapogenins present.

Geography, cytology. Paleotropical, Australian, and Antarctic. From New Zealand to New Guinea, mainly eastern Australia. X = 15.

Taxonomy. Subclass Monocotyledonae. Dahlgren et al. Superorder Liliiflorae; Dioscoreales. APG 3 core angiosperms; Superorder Lilianae; non-commelinid Monocot; Order Liliales.

Species 6. Genera 1; Ripogonum.

Conran,J.G. and Clifford, H.T. (1985). The taxonomic affinities of the genus Ripogonum. Nord. J. Bot. 5, 215–219.