Noronhia rostrata Hong-Wa, 2016

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 : 236-238

73. Noronhia rostrata Hong-Wa , spec. nova ( Fig. 56B , 59 ).

Typus: MADAGASCAR. Prov. Antsiranana: DIANA , Ampasindava , forêt de Andranomatavy, 13°41’41”S 47°59’02”E, 150 m, 8.XII.2009, Ammann et al. 484 (holo-: MO- 6410025 !; iso-: G [ G00180614 ], K, P [ P00853026 ], TEF, US) .

Diagnosis

Noronhia rostrata Hong-Wa can be distinguished from its congeners by its non-woody petioles, its lanceolate leaf blades, terminated by a long acumen, and often bearing domatia, and its sharply rostrate fruits.

Description

Trees to 17 m tall, trunk to 25 cm diameter; young twigs cylindrical, 0.7-1.4 mm diameter, glabrous; bark medium gray, smooth. Leaves opposite, persistent; bud scales rarely persistent; blades medium green above, lighter below, lanceolate to oblong, 6.5- 11.5 3 1.5-3.2 cm, subcoriaceous, glabrous, domatia abundant, base acute to attenuate, margin slightly undulate, apex acuminate, the acumen 10-20 mm long, midrib flat to slightly sunken above, raised below, secondary veins conspicuous, 8-14 per side, 6-12 mm apart, looping 1-2.7 mm from the margin; petiole yellow, 6-15 3 0.9-1.5 mm, not woody, glabrous. Thyrses solitary to geminate, pauciflorous, compact; peduncle 4-6 mm long, moderately pubescent; pedicel 2-4 mm long, moderately pubescent; calyx sparsely pubescent outside, glabrous inside, lobes triangular, 0.9-1 3 0.5-1.2 mm; corolla cream white, cupuliform, 3.2-4.5 mm long, glabrous on both sides, the tube 1-2.8 mm long, lobes ovate, apex acute; corona present, 1.2-1.5 mm long, undivided; stamens 1.5-2.2 mm long, anthers obovate, 1-1.5 mm long; pistil 1.5-2 mm long, stigma capitate. Fruiting pedicel 5-19 3 1-1.3 mm; young fruits green, brownish red when mature, ovoid, 17-24 3 10.5-17.5 mm, surface smooth to slightly ribbed, apex rostrate, the rostrum flattened, ridged, apiculate; dry pericarp 0.3-1.2 mm thick; endocarp crustaceous; seed 10.5-12.5 3 6-7 mm.

Etymology

The specific epithet refers to the distinctive rostrum terminating the fruit apex.

Distribution, ecology and phenology

Noronhia rostrata occurs in rupicolous forests from Ampasindava to Analamerana and Daraina in northern Madagascar ( Fig. 49 ). It produces flowers and fruits from November to July.

Conservation status

The assessment was based on six collections representing five localities, and yielded an EOO of 10,926 km 2, an AOO of 20 km 2, and five subpopulations representing five locations, all but one occurring within the network of protected areas (Ampasindava, Andavakoera-Ambohipiraka, Loky-Manambato, and Tsaratanana). Decline in habitat quality resulting from wood harvesting, forest exploitation, and encroachment will likely continue in the areas not benefiting from protection as well as inside some of the protected areas. With an AOO that is likely less than or equal to 500 km 2, five locations, and a projected continuing decline in habitat quality and in the number of mature individuals, N. rostrata is assigned a preliminary status of “Endangered” [EN B2ab(iii,v)].

238 Boissiera 70

Notes

Noronhia rostrata resembles N. incurvifolia , from which it differs by its flat (vs. folded) leaf blades, bearing domatia (vs. none) on the abaxial side, its cupuliform (vs. subrotate) corolla, the presence (vs. absence) of a corona, and its crustaceous (vs. woody) endocarp. Distinctive features include non-woody petioles, lanceolate leaf blades, terminated by a long acumen, and often bearing domatia, and sharply rostrate fruits.

Paratypi

MADAGASCAR. Prov. Antsiranana: Andrafiamena, Anjahankely , 12°54’49”S 49°19’40”E, 433 m, 6.XI.2010, Burivalova et al. 11 ( G, MO) ; Ampasindava, forêt de Betsitsika , 13°46’28”S 47°59’24”E, 161 m, 9.XI.2009, Gautier et al. 5354 ( G, MO, TEF) ; Andrafiamena, Anjahankely , 12°54’46”S 49°19’37”E, 410 m, 10.XI.2010, Gautier & Ranirison 5381 ( G, MO) ; Anivorano-Nord, Andrafiabe, Mont Antsahabe , 12°54’50”S 49°19’41”E, 408 m, 3.VII.2010, Hong-Wa 719 ( MO, P, TAN) ; ibid. loc., Hong-Wa 720 ( MO, TAN) ; Vohémar, Daraina, forêt d’Antsahabe , 13°12’53”S 49°31’50”E, 460 m, 25. I.2006, Ranirison & Nusbaumer 1111 (Daraina, G, K, MO, TEF) ; Ambanja, Marovato , 13°57’S 48°33’E, 12.XII.1952, Réserves Naturelles 4750 ( P) ; Ambahatra (cours inférieur), 13°54’31”S 49°27’56”E, 80 m, 5.VII.2001, Wohlhauser 457 ( G, MO, P) .

Figures

Fig.56.Photographs of Noronhia Stadtm.ex Thouars

Fig. 59. Noronhia rostrata Hong-Wa.

Fig. 49. Distribution maps of species of Noronhia Stadtm.ex Thouars. N. pervilleana (KnobL.) H. Perrier to N. seyrigii H. Perrier.