Noronhia cordifolia (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 : 76-77

16. Noronhia cordifolia (Labat, M. Pignal & O. Pascal) Hong-Wa & Besnard in Mol. Phylogenet. Evol. 67: 376. 2013 ( Fig. 7E ).

≡ Chionanthus cordifolius Labat, M. Pignal & O. Pascal in Novon 9: 68. 1999.

Typus: M AYOTTE: Mlima Choungi, [12°57’S 45°07’E], 29.XII.1995, Pascal 288 (holo-: P [ P00075021 ]!; iso-: K [ K000691510 ] image seen) .

Description

Trees to 6 m tall; young twigs 1-2.2 mm diameter, glabrous; bark medium gray, slightly rugose. Leaves opposite, persistent; blades dark green above, lighter below, ovate, 4.5-9 3 2-3.5 cm, coriaceous, glabrous, domatia absent, base truncate to cordate, margin flat, apex acuminate, the acumen 3-7 mm long, midrib flat above, flat to slightly raised below, secondary veins conspicuous, 8-10 per side, 6-14 mm apart, looping 1-3 mm from the margin; petiole medium gray to brownish, 0.8-5 3 1-2.3 mm, usually entirely woody, glabrous. Thyrses geminate, pauciflorous, diffuse; peduncle 3-8 mm long, glabrous; pedicel 4-12 mm long, glabrous; calyx lobes ovate, 0.7-0.9 3 0.7-1 mm, glabrous on both sides; corolla yellow, subrotate to cupuliform, 2.2-2.5 mm long, glabrous on both sides, the tube 1.2-1.3 mm long; corona absent; stamens 1.8-1.9 mm long; pistil 1.6-1.8 mm long. Fruiting pedicel 5-7 3 1.5-2 mm; young fruits green, unseen mature, ovoid, 16.5-23 3 13.5-18 mm, surface smooth, apex flat to bluntly pointed, style persistent; dry pericarp 0.8 mm thick; endocarp woody; seed 10.7 3 10.3 mm.

Distribution, ecology and phenology

Noronhia cordifolia occurs in mid-elevation humid forest in northwestern Madagascar and on Mayotte in the Comoro Islands ( Fig. 9 ). It produces flowers and fruits from November to March.

Conservation status

With only four collections representing two localities, the EOO cannot be calculated. However, it was estimated to have an AOO of 8 km 2 and two subpopulations representing two locations, of which only one occurs within a protected area (Réserve forestière des Crêtes du Sud, Mayotte). The subpopulation found in Madagascar is currently known only from three collections made in the 1950s-1960s in an area located between Manongarivo RS and Tsaratanana RNI in heavily degraded habitat. Therefore, N. cordifolia is assigned a preliminary status of “Endangered” [EN B2ab(iii)].

Notes

Noronhia cordifolia can be recognized by its short-petiolate leaves, cordate to truncate leaf base, and diffuse inflorescences. It differs mainly from N. boivinii by its ovate (vs. oblong to elliptic), acuminate (vs. cuspidate to mucronate) leaf blades, thyrsoid inflorescences (vs. fasciculate flowers), and subrotate (vs. urceolate to campanulate), yellowish (vs. pink to reddish) corolla, and by the absence (vs. presence) of a corona. This species was previously known only from the Comoro Islands ( Mayotte). The Malagasy specimens are somewhat different from the type by having slightly shorter petioles that are seldom woody as well as relatively longer inflorescences. They may actually represent a distinct entity but exhaustive comparison with the Comorian specimens is currently unfeasible since the former include only fruits and the latter only flowers. Therefore, a broad N. cordifolia is retained here to accommodate this range of variations, pending additional material, from which molecular data could also be obtained.

Additional specimens examined

MAYOTTE: Grande Terre, sommet du Mt Choungi , [12°57’20”S 45°07’55”E], 21.III.2002, Barthelat & Labarthe 788 ( P) . MADAGASCAR. Prov. Antsiranana: DIANA , Ambanja, Beankany , [14°04’S 48°42’E], 12.XII.1963, Rakotozafy 337 ( P, TAN); ibid. loc., 23. VI .1950, Réserves Naturelles 38 ( TAN); ibid. loc., Saboureau 41 ( P) .

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