Introduction
Ruizia is a monotypic, endangered, genus, from Reunion. It belongs to subfamily Dombeyoideae of Malvaceae sensu APG, and probably to the core of the subfamily, being related to genera such as Dombeya, Trochetia, Astiria, Helmiopsis and Helmiopsiella.
Classification and Synonymy
The foliage of Ruizia is variable. This has resulted in the existence of several synonyms for the single species, including Ruizia lobata Cav., Ruizia laciniata Cav. and Ruizia variabilis Jacq.
Ruizia fragrans Ruiz & Pav. is a synomym for the lauraceous plant Boldea fragrans.
Ruizia cordata Cav. bois de chanteur, Bois de senteur, Bois de senteur blanc
Ruizia cordata is a small tree, which reaches a height of 10m. It is endemic to Reunion, where the number of plants known to remain in the wild is in single figures, the wild populations have been decimated by habitat description, and collection of the bark by local herbalists. It is now protected by law, and a reintroduction program is in progress, managed by the Conservatoire Botanique des Mascarins. It is xerophilous, growing the dryer, lower, areas of the island.
The foliage is alternate, stipulate and petiolate, with the leaves cordate at the base, and roughly triangular in outline. The foliage is also heterophyllous; the juvenile leaves being much palmately dissected with each lobe deeply pinnate, whereas the adult leaves are less so, the adult foliage also being prominently silvery in colour.
The bark is black, and rough.
The species is dioecious. The flowers are borne in clusters of 7 to 15 in leaf axils. They are involucellate, with an deciduous tripartite epicalyx. The calyx is five-lobed, and persistent. The corolla consists of 5 salmon-pink petals, with darker eyes. The male flowers possess 30-40 stamens joined at their bases to form an urn-shape, all of which are antheriferous. The female flowers possess 10, short, styles and 10 carpels, each with two ovules.There are partially covered by a spreading, star-shaped structure presumably homologous to the styles.
The fruit is a small globular capsule. The seeds are weakly three-angled, and unwinged.
Synonyms:of Ruizia cordata include Ruizia diversifolia Jacq., Ruizia laciniata Cav., Ruizia lobata Cav., Ruizia palmata Cav. and Ruizia variabilis Jacq..
Propagation: Seed is available commercially. Germination takes place at 80°F, after 25 to 30 days, and continues for some weeks afterwards.
Images
© 2003, 2007 Stewart R. Hinsley
