Noronhia insularis (Labat, M. Pignal & O. Pascal)

Hong-Wa, Cynthia, 2016, A taxonomic revision of the genus Noronhia Stadtm. ex Thouars (Oleaceae) in Madagascar and the Comoro Islands, Boissiera 70, pp. 1-292 : 129-130

36. Noronhia insularis (Labat, M. Pignal & O. Pascal) Hong-Wa & Besnard in Mol. Phylogenet. Evol. 67: 376. 2013.

≡ Chionanthus insularis Labat, M. Pignal & O. Pascal in Novon 9: 69. 1999.

Typus: M AYOTTE: Bénara, 12°53’S 45°10’E, 350 m, 11.X.1996, Pascal 713 (holo-: P [ P00075020 ]!; iso-: B [100150948] image seen, G [ G00014072 ] image seen, K [ K000691511 ] image seen, MA [ MA 631208] image seen, MO [ MO 176472]!, NY [ NY00277616 ] image seen, P [ P00075017 , P00075018 ]!, WAG [ WAG0004664 ] image seen) .

Description

Trees to 15 m tall, trunk to 15 cm diameter; young twigs cylindrical, 1.5-2 mm diameter, glabrous; bark medium to light gray, slightly rugose, sometimes lenticellate. Leaves opposite, persistent; bud scales rarely persistent; blades dark green above, lighter below, lanceolate, 12.5-20 3 3-6 cm, chartaceous, glabrous, domatia rare, base acute, margin flat to slightly undulate, apex acuminate, the acumen 10-18 mm long, midrib flat above, raised below, secondary veins conspicuous, 11-14 per side, 13-22 mm apart, looping 2-4 mm from the margin; petiole light gray, 7-13 3 1.5-2 mm, entirely woody, glabrous. Thyrses geminate, pauciflorous, compact; peduncle 4 mm long, moderately pubescent; pedicel 6 mm long, moderately pubescent; calyx moderately pubescent outside, glabrous inside, lobes triangular, 1.5 3 2 mm; corolla yellow, subrotate, 6 mm long, glabrous on both sides, the tube 1 mm long, lobes deltate, apex acute; corona absent; stamens 2.3-2.6 mm long, anthers suborbicular, 1.3-1.6 mm long; pistil 2.7 mm long, stigma bilobed. Fruiting pedicel 12 3 2.2 mm; young fruits green, brownish when mature, ellipsoid, 42 3 20 mm, surface ribbed, apex rostrate, the rostrum flattened, ridged, truncate; dry pericarp 0.8 mm thick; endocarp woody; seed 33 3 16 mm.

Distribution, ecology and phenology

Noronhia insularis occurs in low- to mid-elevation humid forests on Mayotte and Grande Comore in the Comoro Islands ( Fig. 19 ). It produces flowers and fruits from August to November.

Conservation status

Noronhia insularis is currently known from five collections representing five localities. The estimates provided an EOO of 1,535 km 2, an AOO of 20 km 2, and four subpopulations representing four locations, two of which occur within protected areas (Réserves forestières de Tchaourembo et de Bénara). The subpopulations in Grande Comore and those that are outside of protected areas in Mayotte are heavily impacted by habitat degradation and habitat loss resulting from land conversion, thereby reducing the number of mature individuals. Therefore, N. insularis is assigned a preliminary status of “Endangered” [EN B1ab(ii,iii,v)+2ab(ii,iii,v)].

130 Boissiera 70

Notes

Noronhia insularis can be recognized by its lanceolate leaf blades, subrotate, yellow flowers lacking a corona, and elongate, ribbed and rostrate fruits. It differs from N. aminae by its rugose (vs. smooth) bark, lanceolate (vs. oblong) leaf blades, the absence (vs. presence) of a corona, and its ribbed (vs. rugose) fruits.

Additional specimens examinated

COMOROS: Grande Comore (Ngazidja), Nioumbadjou, chemin du capitaine Dubois en direction de N’Kourani , 9.X.1984, Loup 71 ( P) . MAYOTTE: Grande Terre, Tsararano , RF des crêtes du centre Mont Bénara, 5.II.2006, Barthelat et al. 1571 ( BR, G, K, MO); Tchaourembo, Réserve Forestière de Tchaourembo , 113. XI.2002, Barthelat et al. 1069 ( G, K, MO, P); Bénara , 12°50’S 45°10’E, 575 m, 1.VIII.1996, Pascal 617 ( G, K, MO, P) .

Figures

Fig.19. Distribution maps of species of Noronhia Stadtm.ex Thouars.N.edentata (H.Perrier) Hong-Wa to N.insularis (Labat,M.PignaL & O. PascaL) Hong-Wa & Besnard.