Noronhia disjuncta

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 : 97-98

24. Noronhia disjuncta Hong-Wa, spec. nova ( Fig. 16 ).

Typus : MADAGASCAR. Prov. Antsiranana: DIANA, RNI No 4 Tsaratanana, Antsahamanara , Beangona , 14°02’06”S 48°47’08”E, 1400 m, 28.XI.2000, Randria et al. 16 (holo-: MO-6615569!; iso-: G [ G00341628 ]!, K!, P [ P00641023 ]!, TAN!) .

Diagnosis

Noronhia disjuncta Hong-Wa can be distinguished from its congeners by its light gray to whitish bark, its ovate leaf blades and its compact inflorescences with red flowers.

Description

Trees to 12 m tall, trunk to 17 cm diameter; young twigs cylindrical, 1.3-2.3 mm diameter, glabrous; bark light gray to whitish, smooth to somewhat rugose, with scattered lenticels. Leaves opposite, persistent; bud scales persistent; blades medium green above, lighter below, ovate to broadly elliptic, 8.5-13.5 3 3-5.5 cm, coriaceous, glabrous, domatia absent, base rounded to acute, margin flat to slightly undulate, apex acuminate, the acumen 4-9 mm long, midrib slightly sunken above, distinctly raised below, secondary veins mostly conspicuous below, 9-13 per side, 11-17 mm apart, looping 2.5-4.5 mm from the margin; petiole medium gray, 7-13 3 1.8-2.7 mm, entirely woody, glabrous. Thyrses geminate, multiflorous, compact; peduncle 6 mm long, moderately pubescent; pedicel 4-9 mm long, sparsely pubescent; calyx sparsely pubescent outside, glabrous inside, lobes triangular, 1.5 3 1-2 mm; corolla red outside, whitish inside, urceolate, 3-4.5 mm long, glabrous on both sides, the tube 1.5-2.7 mm long, lobes deltate, apex acute; corona present, 1.5-2.6 mm long, undivided; stamens 2-2.5 mm long, anthers obovate, 1.6 mm long; pistil 2.5-2.6 mm long, stigma capitate to slightly bilobed. Fruiting pedicel 4-13 3 1-2 mm; young fruits green, black when mature, subglobose to ovoid, 12.9-18.8 3 11.1-14.4 mm, surface smooth, apex flat to rostellate, the rostellum circular, obtuse, with the persistent style; dry pericarp 0.5-1.1 mm thick; endocarp woody; seed 7.6-12.2 3 6.4-8.7 mm.

Etymology

The specific epithet refers to the somewhat disjunct distribution of this species.

Distribution, ecology and phenology

Noronhia disjuncta occurs in mid- to high-elevation humid forests on basement rocks from Tsaratanana and Antalaha, in the north, to Ranomafana, in the south ( Fig. 9 ). It produces flowers and fruits from November to January.

Conservation status

Although Noronhia disjuncta is currently known only from nine collections representing nine localities, it has an EOO of 41,247 km 2, an AOO of 36 km 2, and six subpopulations representing six locations, all of which occur within protected areas (Anjanaharibe-Sud, Marojejy, Ranomafana, Tsaratanana, and Tsaratanana-Ambohi-mirahavavy-Corridor Marojejy). With all the collections made at high elevations within these protected areas, little to no threat is expected to affect this species in the near future. Therefore, N. disjuncta is assigned a preliminary status of “Least Concern”.

98 Boissiera 70

Notes

Noronhia disjuncta resembles both N. humblotiana (H. Perrier) Hong-Wa and N. mangorensis H. Perrier , but can be distinguished by its thyrsoid inflorescences (vs. fasciculate flowers in both of the other species), smooth (vs. rugose) fruit surface, and flat to rostellate (vs. apiculate) fruit apex. The new species can be recognized by its light gray to whitish bark, ovate leaf blades, and compact inflorescences with red flowers.

Paratypi

MADAGASCAR. Prov. Antsiranana: Marojejy PN , 14°28’57”S 49°38’12”E, 1100- 1600 m, 19-24. I .1994, Malcomber et al. 2701bis ( MO, TAN); Andapa, Ambodisatrana , 14°32’S 49°26’E, 1000-1100 m, 2.VIII.1997, McPherson 17165 ( MO, TAN); Bealampona , Anjanaharibe-Sud RS , 14°44’45”S 49°29’40”E, 890-1041 m, 14.IX.1994, Ravelonarivo et al. 377 ( MO, P, TAN); ibid. loc ., 14°43’42”S 49°27’57”E, 1570 m, 1.XII.2003, Schmidt 4377 ( MO). Prov. Fianarantsoa: Ranomafana PN , 21°15’S 47°27’E, 1100 m, 11-15.XI.1991, Malcomber et al. 1077 ( G, MO, P, TAN); ibid. loc ., 21°16’S 47°26’E, 1000-1100 m, 18-31. I .1993, Malcomber et al. 2034 ( MO, P); ibid. loc ., 21°15’30”S 47°25’00”E, 950-1150 m, 21. I .1993, Turk & Randrianasolo 255 ( G, MO, P, TAN). Prov. Mahajanga: Tsaratanana Massif , 1800-2000 m, 11. V .1974, Gentry 11688 ( MO, P, TAN) .

Figures

Fig. 16. Noronhia disjuncta Hong-Wa.

Fig. 9. Distribution maps of species of Noronhia Stadtm.ex Thouars. N. christenseniana Dubard to N. domatifera Bosser.