Noronhia obovata (Baker) Hong-Wa & Callm., comb. nova.

Ξ Olea obovata Baker, Fl. Mauritius: 219. 1877.

Ξ Chionanthus ayresii A. J. Scott in Kew Bull. 33: 570. 1979 [non C. obovatus Raf., New Fl. 3: 87. 1838].

Ξ Noronhia ayresii (A. J. Scott) Hong-Wa & Besnard in Mol. Phylogenet. Evol. 67: 375. 2013 [nom. illeg.].

Typus: MAURITIUS: s.loc., 27.II.1864, Ayres s.n. (holo-: K [K000233211]!; iso-: GH [GH00075134] image seen).

Observations. – Noronhia obovata is a small treelet (2-2.5 m) (Fig. 1D), exceptionally a medium-sized tree, that can be distinguished by its grayish bark and its very short inflorescences (3-8 mm) and fruits (10-18 mm) (SCOTT & GREEN, 1981). It is found in drier areas than the two other native species of Noronhia, at sites from 200 to 700 m elevation. In addition to facing the same threats as those described above for N. broomeana var. broomeana, some of the remnant areas of forest where N. obovata occurs are leased for ranching of alien deer in which the understory is regularly cut, browsed and heavily trampled.

Conservation status. – Despite having a somewhat larger EOO (491 km 2) than Noronhia broomeana var. broomeana, the AOO of N. obovata is similar (28 km 2; calculation following GEOCat version ss, see BACHAM & al., 2011). Norhonia obovata may no longer occur at some historically known localities such as Chamarel Hill, and only one of those where it is currently known to occur (Brise Fer) has actively weeded vegetation. As a consequence, this species is undergoing continuous habitat degradation, although some individuals occur within a protected area (Corps de Garde Nature Reserve). The largest population is located on Le Pouce, where most of the plants occur outside of the Nature Reserve in the surrounding State Lands, in areas classified as a Mountain Reserve (Fig. 2C). The other 7 or 8 known localities have few reproductive individuals, hence the total number of reproductive individuals of N. obovata is estimated to be less than 100 plants. This species should therefore be considered as “Endangered” [EN B1ab(ii,iii,iv); C1+2a(i)] according to the IUCN Red List Criteria (IUCN, 2012).

Specimens examined. – MAURITIUS. Dist. Black River: Chamarel Hill, 19.VI.1939, Vaughan s.n. (MAU [MAU 0014549]); Brise Fer, IV.2004, Sevathian s.n. (MAU [MAU 0014562]); Cabinet, 7.III.1958, Vaughan s.n. (MAU [MAU 0014550]); Mt. Corps de Garde, 29.III. 2001, V. Florens & Sevathian s.n. (MAU [MAU 0014558]); Magenta, 26.VIII.1984, Wellings s.n. (MAU [MAU 0014557]); Trois Mamelles, 119 m, 20°18’58’’S 57°26’49’’E, 31.III.2011, Pynee, Byng & d’Argent s.n. (MAU [MAU 0002716]); Sine loc., s.d., Bijoux s.n. (MAU [MAU 0014548]). Dist. Grand Port: Mt. Bambou, IX.2003, Sevathian s.n. (MAU [MAU 0014561]) ; Mt. Brisé, 200 m, 20°20’ 46’’S 57°45’10’’E, 30.III.2007, Pynee & Chitbauhaal s.n. (MAU [MAU 0014563]). Dist. Port Louis: Le Pouce, 1.VI.1969, Guého s.n. (MAU [MAU 0014552]); ibid. loc., 21.V.1971, Guého s.n. (MAU [MAU 0014555]); ibid. loc., 654 m, 20°12’01’’S 57°31’ 33’’E, 28.VIII. 2008, Pynee, Sevathian, Seepaul & Nabee s.n. (MAU [MAU 0014600]); ibid. loc., 613 m, 20°12’58’’S 57°31’49’’E, 29.VII.2011, Baider & V. Florens CB 2461 (MAU [MAU 0015021]).