Noronhia christenseniana

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 : 65-67

12. Noronhia christenseniana Hong-Wa, spec. nova ( Fig. 7A , 8 ).

Typus : MADAGASCAR. Prov. Antsiranana: DIANA, Diégo II, Ramena, env. 2 km à l’W d’Andavakoera, près de la grotte et du campement la Casa Aventura, 12°19’41’’S 49°20’26’’E, 76 m, 3.VIII.2007, Hong-Wa et al. 517 (holo-: MO-6615555!; iso-: CNARP!, G [ G00341618 ]!, K!, P!, TAN!) .

Diagnosis

Noronhia christenseniana Hong-Wa can be distinguished from other members of the genus by its widely obovate to rhombic leaf blades, distinctly terminated by a long cusp and its diffuse inflorescences with red flowers.

Description

Shrubs or trees to 10 m tall, trunk to 15 cm diameter; young twigs cylindrical, 0.7-1.2 mm diameter, glabrous; bark medium gray, smooth. Leaves opposite, persistent; bud scales deciduous; blades medium green above, lighter below, broadly obovate to rhombic, 3.5-7.5 3 1.5-4.5 cm, coriaceous, glabrous, domatia casual, base attenuate, margin flat to undulate, slightly revolute, apex cuspidate, the cusp 10-20 mm long, midrib slightly sunken above, distinctly raised below, secondary veins conspicuous only below, 6-10 per side, 4-9 mm apart, looping 1-3.2 mm from the margin; petiole light gray, 4-6 3 0.6-1.3 mm, entirely woody, glabrous. Thyrses solitary to geminate, pauciflorous, diffuse; peduncle 12-20 mm long, glabrous; pedicel 4-8 mm long, glabrous; calyx glabrous on both sides, lobes triangular, 1 3 1-2 mm; corolla red, urceolate, 2.5-4 mm long, glabrous on both sides, the tube 1.8-2 mm long, lobes deltate, apex acute; corona present, 0.8-1.5 mm long, slightly lobed; stamens 1.5-1.8 mm long, anthers oblong, 1.2 mm long; pistil 1.8-2 mm long, stigma bilobed. Fruiting pedicel 8-18 3 0.5-1 mm; young fruits green, purplish brown when mature, ovoid, 9-15.5 3 7.5-9 mm, surface smooth, apex apiculate to rostellate, the rostellum flattened, truncate, with the persistent style; dry pericarp 0.4-0.8 mm thick; endocarp crustaceous; seed 8-10 3 4-5.5 mm.

Etymology

This name honors the founders of the Christensen Fund Graduate Fellowship Program in Plant Conservation, which provided me with support during my graduate studies at the University of Missouri-St. Louis, thus allowing me to carry out a comprehensive study of Noronhia .

Distribution, ecology and phenology

Noronhia christenseniana occurs in low-elevation semi-deciduous forests in the north, from Montagne des Français to Ankarana ( Fig. 9 ). It produces flowers and fruits from August to March.

Conservation status

Based on 18 collections representing 13 localities, the assessment resulted in an EOO of 4,069 km 2, an AOO of 48 km 2, and seven subpopulations representing six locations, of which three occurs within the network of protected areas (Ankarana, Loky-Manam-bato, and Montagne des Français). Noronhia christenseniana is narrowly distributed (although with an actual AOO that is likely larger than estimated here) in an area that is affected by deforestation, wood harvesting, charcoal production, and illegal and/or artisanal mining, resulting in habitat degradation and loss. It is therefore assigned a preliminary status of “Vulnerable” [VU B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)].

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Notes

Noronhia christenseniana is in some ways similar to N. clarinerva Hong-Wa and N. intermedia Hong-Wa, but can be distinguished by its thyrsoid inflorescences (vs. fasciculate flowers), red corolla (vs. pinkish in N. clarinerva and pale green in N. intermedia ) and crustaceous (vs. woody) endocarp. Distinctive features such as the widely obovate to rhombic leaf blades with a long cuspidate apex and diffuse inflorescences with red flowers make it easy to recognize N. christenseniana .

Paratypi

MADAGASCAR. Prov. Antsiranana: Mahamasina, Ankarana RS, 12°56’56”S 49°07’39”E, 22.III.2007, Bardot-Vaucoulon & Toly 1528 ( K, MO, P, TAN) ; Ramena, Andavakoera , 12°19’57”S 49°21’19”E, 172 m, 4.VIII.2007, Hong-Wa et al. 538 ( TAN) ; ibid. loc., Hong-Wa et al. 539 ( TAN) ; Ankarana RS, [12°49’S 49°01’E], I.1969, Morat 3046 ( P) ; Daraina, forêt d’Antsaharaingy , 12°54’52”S 49°39’25”E, 75-660 m, 3.III.2004, Nusbaumer & Ranirison 1533 (Daraina, G, K, MO, P) ; Antafiankoroka, Montagne des Français , 12°22’27”S 49°21’27”E, 204 m, 4.II.2005, Rabefarihy 46 ( MO, P, TAN) ; Ampitiliantsambo, Montagne des Français , 12°22’55”S 49°23’05”E, 359 m, 25.I.2005, Randrianarivelo et al. 167 ( MO, P, TAN) ; Daraina , forêt de Binara, 13°14’16”S 49°37’32”E, 250 m, 27.III.2004, Ranirison 500 (Daraina, G, K, MO, P, TEF) ; ibid. loc., forêt d’Antsaharaingy , 12°54’34”S 49°39’57”E, 90 m, 18.IV.2004, Ranirison 691 (Daraina, G, K, MO, TEF) ; Andrafiabe, Mont Andrahona, 3 km au NE d’Andrafiabe , 12°28’49”S 49°26’56”E, 400 m, 31.I.2005, Ratovoson et al. 830 ( CNARP, MO, P, TAN) ; Montagne des Français, forêt d’Antaolanaomby , 12°22’25”S 49°21’11”E, 385 m, 22.III.2007, Ratovoson 1280 ( CNARP, G, MO, P, TAN) ; Mosorolava, Ampombiantambo, forêt d’Antsoroby , 12°42’13”S 48°58’12”E, 75 m, 23.IX.2007, Ratovoson et al. 1331 ( CNARP, G, MO, P, TAN) ; Montagne des Français, Andavakoera , 12°21’10”S 49°21’06”E, 94 m, 12.VIII.2004, Razafitsalama et al. 606 ( CNARP, MO, P, TAN) ; Ankarana RS, [12°49’S 49°01’E], 8.VIII.1952, Service Forestier 5419 ( P, TEF) ; Montagne des Français , [12°22’S 49°21’E], 7.VIII.1978, Service Forestier 29260 ( TEF) ; ibid. loc., 12.XI.1979, Service Forestier 29597 ( TEF) ; ibid. loc., Service Forestier 29600 ( TEF) ; ibid. loc., 24.IX.1980, Service Forestier 29969 ( TEF) .

Figures

Fig. 7. Photographs of Noronhia Stadtm.ex Thouars. A. Noronhia christenseniana Hong-Wa [Ratovoson 1280]; B. Noronhia clarinerva Hong-Wa [Nusbaumer 821]; C. Noronhia cochleata Labat, M. PignaL & O. PascaL [Labat 3258]; D. Noronhia comorensis S. Moore [Barthelat 537]; E. Noronhia cordifolia (Labat, M. PignaL & O. PascaL) Hong-Wa & Besnard [Barthelat 788].

Fig. 8. Noronhia christenseniana Hong-Wa.

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