Turraea sambavensis, J.-F. Leroy & Lescot, 2024

Callmander, Martin W. & Nusbaumer, Louis, 2024, Descriptions of ten new species of Turraea L. (Meliaceae, Turraeeae) from Madagascar with notes on the species described by Buchenau, Adansonia (3) 46 (11), pp. 103-128 : 116

Turraea sambavensis

J.-F. Leroy & Lescot ex Callm. & Nusb., sp. nov.

( Fig. 8 )

DIAGNOSIS. — Turraea sambavensis sp. nov. can be distinguished by its large flowers (5-7.5 cm long), white becoming sulfur yellow with a sweet fragrance, the length of its staminal tube ([3-]5-5.5[- 6] cm long) and appendices (4.5-5 mm long) with a tapering blade, twisted at apex, and by its glabrous capsule.

TYPUS. — Madagascar • Sava Region [Prov. Antsiranana], au Sud de Sambava ; [14°18’00”S, 50°11’30”E]; 30.XI-1.XII.1966; fl., imm. fr.; Service Forestier 27118 (holo-, P [ P05275078 ]!; iso-, G [ G00408541 ]!, MO!, P [ P00580369 ]!, TEF) .

PHENOLOGY. — Flowers in September to December, immature fruits in November-December.

DISTRIBUTION AND ECOLOGY. — The new species is restricted to littoral forests at low elevation.

ETYMOLOGY. — The species epithet refers to the city of Sambava where the new species has been collected.

CONSERVATION STATUS. — The new species has not been collected since 1966 and is restricted to highly threatened littoral forests south of Sambava that are under severe pressure from local communities through logging for construction and firewood, slash-and-burn agriculture and large-scale oil palm plantations ( Consiglio et al. 2006; De Block 2022). The new species has not been collected or observed for more than fifty-five years and could therefore be possibly extinct. With an AOO of 4 km ² and two known localities, none situated within a protected area network, Turraea sambavensis sp. nov. is therefore preliminary assessed as “Critically Endangered (PE)” [CR (PE)] in accordance with IUCN Red List Categories and Criteria ( IUCN 2012).

ADDITIONAL SPECIMENS EXAMINED. — Madagascar • Sava Region [Prov. Antsiranana], env. de Sambava ; [14°15’S, 50°09’E]; 1-5 m; 28.XI-3.XII.1950; Humbert & Capuron 24387 ( P [ P05275077 ]) • Cant. Ambohitalanana, distr. Antalaha ; 19.XII.1956; fl.; Réserves Naturelles 7972 ( P [ P05275076 ]) • Au Sud de Sambava ; [14°18’00”S, 50°11’30”E]; 3.XII.1950; fl.; Service Forestier 899 ( P [ P05275075 ]) • Sambava ; [14°18’00”S, 50°11’30”E]; 29.IX.1954; fl.; Service Forestier 9247 ( G [ G00408545 ], P [ P00853200 , P00800359 ], TEF) .

DESCRIPTION

Small to medium-sized trees, 10-15 m tall, 15-20 cm in diam.; young stems brownish, longitudinally striated, glabrous. Leaves unifoliolate; leaf blade broadly elliptic to suborbicular, chartaceous to subcoriaceous, glabrous, (2.5-)3.5-5(-7) × (1-)1.5-2.5(-3) cm, base acute to obtuse, margin entire, sub-revolute, apex rounded or obtuse to mucronate, adaxial surface dark green, abaxial surface pale green, domatia present, in pockets at the axils of the secondary veins; primary and secondary veins prominent on both surfaces; reticulum slightly distinct; petiole 3 mm long, puberulent to glabrescent. Inflorescences pauciflorous, 1(-2) flowers. Flower buds enlarged and obtuse at the apex. Flowers 5-7.5 cm long; pedicel 6-10 mm long, glabrous to glabrescent. Calyx cupuliform, 4 × 3.5 mm, 5-lobed, each lobe with an apical tooth 2-2.5 × 1.2 mm, glabrous to glabrescent on the outside, tomentose on the inside. Corolla white becoming sulfur yellow with a sweet fragrance (Humbert & Capuron 24387, Service forestier 899) of 5 linear-spathulate petals, longer than the staminal tube, 50-75 mm long, 1 mm wide at base, 2 mm wide in the proximal part, apex acute, puberulent outside, glabrous inside. Staminal tube cylindrical, slightly enlarged distally, (30-)50- 55(-60) mm long, glabrous outside, papillose on the inside; appendices 10 with a tapering blade, twisted at apex, bifid at base, 4.5-5 mm long, glabrous; anthers 10, subsessile, oblong, 1 × 0.3 mm, apiculate, apicule c. 0.5 mm; ovary oblate to globose, 2 × 1 mm, with sparse hairs, locules (8-)10(-14), each with 2 superposed ovules; style exserted 5-10 mm, beyond the staminal tube 0.3 mm in diam. Receptaculum pollinis ellipsoid, 3 × 1.5 mm; stigma capitate, 0.4 × 1.5 mm. Fruit a capsule, globose ovoid, 10-12 mm diam., blackish, dehiscing by 10 valved, glabrous; pericarp 0.2 mm thick; calyx persistent. Seeds centrally grouped, reniform, 3 × 2 mm; testa brownish, smooth, 0.1 mm thick; aril present.

NOTES

Turraea sambavensis sp. nov. ressembles Turraea geayi Danguy in its leaves with domatia and staminal tube bearing 10 long appendices. The latter species also occurs in littoral forests of the east coast. The new species can be distinguised by its larger leaves and flowers, and its ovary with (8-)10(-14) locules (vs 5 in T. geayi ).

We attribute this name to Leroy & Lescot. No new collections have been gathered since their unpublished description.

The recently described Paracephaelis sambavensis De Block ( Rubiaceae ), also “Critically Endangered” and possibly extinct has been collected in the same forest and on the same day as the type of Turraea sambavensis sp. nov. by René Capuron (1921-1971).

Figures

FIG. 8. — Turraea sambavensis J.-F. Leroy & Lescot ex Callm. & Nusb., sp. nov.: A, immature fruit and a flower; B, flowering stem; C, domatia; D, ovary; E, apical view of staminal tube with receptaculum pollinis; F, calyx; G, various views of stamens; H, front side view of petal. A, Service Forestier 24387; B-H, Service Forestier 9247. Drawings: Jacqueline Lemeux. Scale bars: A, H, 1 cm; B, 5 cm; C, D, G, 1 mm; E, 3 mm; F, 40 mm.