Noronhia obcordifolia

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 : 186-188

56. Noronhia obcordifolia Hong-Wa, spec. nova ( Fig. 41 ).

Typus: MADAGASCAR. Prov. Antsiranana: DIANA, Diégo II, Ramena, env. 2 km à l’O d’Andavakoera , près de la grotte et du campement la Casa Aventura, 12°19’57’’S 49°21’19’’E, 172 m, 4.VIII.2007, Hong-Wa et al. 535 (holo-: MO- 6615565 !; iso-: CNARP!, G [ G00341625 ]!, P!, TAN!) .

Diagnosis

Noronhia obcordifolia Hong-Wa can be distinguished from its congeners by its coriaceous, heart-shaped leaves and its apiculate fruits, somewhat covered with a white pellicle.

Description

Shrubs to 4 m tall; young twigs cylindrical, 1-1.3 mm diameter, glabrous; bark dark gray, smooth. Leaves opposite, persistent; bud scales persistent; blades medium gray, cordiform, 3-4 3 2-3 cm, coriaceous, glabrous, domatia absent, base acute, margin slightly revolute, apex obcordate, midrib slightly sunken above, raised below, secondary veins barely visible, 5-6 per side, 5-7 mm apart, looping 1.5-2 mm from the margin; petiole medium gray, 4 3 1.2-1.6 mm, entirely woody, glabrous. Flowers unseen, but fruits solitary. Fruiting pedicel 7-8 3 1-1.2 mm; young fruits green, reddish when mature, ovoid, 12.2-12.6 3 7.4-7.8 mm, smooth, sometimes covered with a white pellicle, apex apiculate, with the persistent style; dry pericarp 0.4 mm thick; endocarp woody.

Etymology

The specific epithet refers to the inverted heart-shaped leaf blade, with its distinctive obcordate apex.

Distribution, ecology and phenology

Noronhia obcordifolia occurs in low-elevation dry forests on limestones on Montagne des Français in the north ( Fig. 36 ). It has been collected in fruits in August.

Conservation status

Noronhia obcordifolia is known only from three collections from the newly established protected area of Montagne des Français. Because of its close proximity to the city of Diégo-Suarez, the forest on Montagne des Français has played an important role in supplying the population with charcoal and other products, providing refuge to fugitive criminals, and favoring other illegal activities such as small-scale cannabis cultivation. This rocky outcrop has also become a favorite destination for rock climbers in recent years. Although its new status as a protected area should gradually reduce the impacts of these threats, habitat degradation as well as habitat alteration resulting from illicit exploitation and invasive species will likely persist. Therefore, N. obcordifolia is assigned a preliminary status of “Critically Endangered” [CR B2ab(iii,v)].

188 Boissiera 70

Notes

Noronhia obcordifolia most closely resembles N. lowryi , from which it differs by its smooth (vs. rugose) bark, woody (vs. non-woody) petioles, cordiform (vs. elliptic) leaf blades, and ovoid (vs. pyriform) fruits with an apiculate (vs. flat) apex. Distinctive features include coriaceous, inverted heart-shaped leaves with an obcordate apex, and apiculate fruits somewhat covered with a white pellicle.

Paratypi

MADAGASCAR. Prov. Antsiranana: Ramena, Andavakoera , 12°19’41”S 49°20’26”E, 76 m, 3.VIII.2007, Hong-Wa et al. 524 ( CNARP, MO, P, TAN); ibid. loc., 12°19’57”S 49°21’19”E, 172 m, 4.VIII.2007, Hong-Wa et al. 544 ( TAN) .

Figures

Fig. 41. Noronhia obcordifolia Hong-Wa.

Fig. 36. Distribution maps of species of Noronhia Stadtm. ex Thouars.N. maculata Hong-Wa to N. perrieriana Hong-Wa.