Noronhia populifolia H. Perrier

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 : 218

67. Noronhia populifolia H. Perrier in Mém. Inst. Sci. Madagascar, Sér. B, Biol. Vég. 2: 298. 1949 ( Fig. 51 ).

Typus: M ADAGASCAR. Prov. Antsiranana: Sambirano , bord de l’Andranomalaza, [14°19’00’’S 48°17’30’’E], VIII.1907, Perrier de la Bâthie 8825 (holo-: P [ P00418101 ]!) .

Description

Trees to 16 m tall; young twigs cylindrical, 2-2.5 mm diameter, glabrous; bark medium to light gray, smooth to slightly rugose. Leaves opposite, persistent; bud scales persistent; blades light green, oblong to ovate, 10.5-22 3 5.5-8 cm, subcoriaceous, glabrous, domatia absent, base rounded, margin flat to undulate, apex acuminate, the acumen 13-36 mm long, midrib slightly sunken above, raised below, secondary veins conspicuous, 9-14 per side, 13-16 mm apart, looping 3-4 mm from the margin; petiole yellowish to brown, 10-16 3 1.9-2.6 mm, not woody, glabrous. Thyrses geminate to fasciculate, pauciflorous, compact; peduncle 8-11 mm long, moderately pubescent; pedicel 4-8 mm long, moderately pubescent; calyx moderately pubescent outside, glabrous inside, lobes triangular, 1-2.5 3 1.4-2 mm; corolla pink, cupuliform, 5-5.5 mm long, glabrous on both sides, the tube 2.5-3 mm long, lobes widely ovate; corona present, 1.7-2 mm long, undivided; stamens 2-2.5 mm long, stamens widely obovate, 1.5-1.6 mm long; pistil 2.2-2.5 mm long, stigma capitate. Fruiting pedicel 5 3 3 mm; young fruits green, blackish when mature, oblong to subglobose, 28.5-35 3 24-30 mm, surface verrucose, apex apiculate; dry pericarp 1.7-2.2 mm thick; endocarp woody; seed 25 3 23 mm.

Distribution, ecology and phenology

Noronhia populifolia occurs in mid-elevation humid forests and sandstones in the Sambirano region in the northwest ( Fig. 49 ). It has been collected in flowers and fruits in October.

Conservation status

With just a single collection made in 1907 from an area that is not protected and that has been gradually degraded as a result of agriculture and wood harvesting, N. populifolia is assigned a preliminary status of “Critically Endangered”, and could possibly be extinct [CR(PE) B2(iii)].

Notes

Noronhia populifolia can be recognized by its non-woody petiole, broadly ovate leaf blades with a long apex, somewhat compact inflorescences bearing pink flowers, and large, verrucose fruits with a thick pericarp. It differs from N. pervilleana by its nonwoody (vs. woody) petioles, cupuliform (vs. rotate), pink (vs. white) flowers, and oblong to subglobose (vs. ovoid), verrucose (vs. smooth to punctate) fruits. This species is known only from the type specimen, collected over a century ago close to a current protected area (Manongarivo). Despite numerous botanical explorations in the surrounding areas over the last five decades, no other material is available, suggesting perhaps a very small and restricted population or that the species is now extinct.

Figures

Fig. 51. HoLotype of Noronhia populifolia H. Perrier.

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