Ochna sambiranensis Callm. &Phillipson, 2012

Callmander, Martin, W. & Phillipson, Peter B., 2012, Notes on the genus Ochna L. (Ochnaceae) in Madagascar, Candollea 67 (1), pp. 142-144 : 143-144

Ochna sambiranensis Callm. &Phillipson , nom. nov.

Ξ Polythecium macranthum Tiegh. in Ann. Sci. Nat. Bot. ser 8, 16: 370. 1902.

Typus: MADAGASCAR. Prov. Antsiranana: Nosy Be , meeresstrand, VII.1879, fl., Hildebrandt 3192 (holo-: P [ P00568727 ]!; iso-: G [ G00353496 ]!, P [ P00568728 , P005 68729]!) .

Observations. – This species was first described as Polythecium macranthum Tiegh. , based on a single collection (Hildebrandt 3192) from Nosy Be. The species was placed in synonymy by PERRIER DE LA BATHIE (1941), along with seven other species of Polythecium described by Van Tieghem, under a very broadly-circumscribed Diporidium ciliatum (Lam.) Kuntze (= Ochna ciliata Lam. ). We have found a number of additional collections also from lowland forests in the Sambirano region of NW Madagascar that are an excellent match for the type collection, mostly modern collections that were not availabletoPerrier de laBâthie. The specimens all possess a distinct suite of characters, and we believe they represent a well-marked species that should now be recognised in the genus Ochna . A new combination in Ochna based on the existing epithet is not possible, because this name already exists for adifferent species ( O. macrantha Baker ,also from Madagascar). We therefore propose the new name O. sambiranensis for this species. VAN TIEGHEM (1902b: 370) noted the following diagnostic characters for the species: its relatively large leaves with their conspicuously ciliate margins and mucronate apices and itslarge flowersinafew-flowered racemewithahighlycontracted axis, resembling an umbel ( Fig. 1 ).Inaddition we add that O. sambiranensis can be distinguished from O. ciliata to which it is probably most closely related, by its coriaceous, narrowly elliptic to lanceolate leaves, with a rather obscure tertiary venation (vs. membranous, obovate to oblanceolate leaves, with conspicuous tertiary venation); with its flowers borne on much longer pedicels (usually> 20 mm long), often developing before the leaves (vs. shorter pedicels and with flowers concurrent with the leaves).

Etymology. – The species epithet refers to the Sambirano biogeographicregion towhich Ochna sambiranensis appears to be restricted.

Figures

Fig. 1. – Living plant of OCHna sambiranensis Callm. & Phillipson at Kalabenono corresponding to Callmander & al. 703. [Photo: M. W. Callmander]