Xylopia marojejyana D. M.Johnson & N. A.Murray, 2020

Johnson, David M. & Murray, Nancy A., 2020, A revision of Xylopia L. (Annonaceae): the species of Madagascar and the Mascarene islands, Adansonia 42 (1), pp. 1-88 : 74

30. Xylopia marojejyana D. M.Johnson & N. A.Murray , sp. nov. ( Fig. 25F-H )

Species resembling Xylopia humbertii in its elliptic subcoriaceous leaves with the blades decurrent on the petiole, but differing in the exfoliating bark of the twigs, the leaf blades 5.8-7.3 cm long and 3.1-3.3 cm wide with a narrow sharp-pointed acumen 7-10 mm long, and the conspicuous reticulum formed by the secondary and higher-order veins on the adaxial blade surface. Xylopia humbertii , in contrast, lacks exfoliating bark on the twigs, has leaves 5.2-6.3 cm long and 2.2-2.8 cm wide with a blunt acumen 3-5 mm long, and the secondary and higher-veins only slightly raised and not conspicuous on the adaxial blade surface. The monocarps of X. marojejyana , sp. nov., which are oblong, short-stipitate, and 4.0- 4.9 cm long and 2.0- 2.3 cm wide with strong oblique wrinkles, will distinguish it from many other Malagasy Xylopia species.

TYPE. — Madagascar. Prov. Antsiranana, Réserve naturelle de Marojejy , western slopes of Mt. Beondroka , 14°27’S, 49°47’E, 660-830 m, 23-24.X.1989 (fr.), Miller & Randrianasolo 4423 (holo-, MO).

DISTRIBUTION, ECOLOGY AND CONSERVATION STATUS. — Xylopia marojejyana , sp. nov., is known only from the Réserve Naturelle de Marojejy, where it was collected from the forested slopes of Mount Beondroka at an elevation of 660-830 meters ( Fig. 29 ). The Marojejy massif area has been documented as a center of plant microendemism, with endemic species from many different families represented. Most of the endemics, however, are typical of higher elevation vegetation, for example Weinmannia in the Cunoniaceae ( Bradford & Miller 2001).The type specimen with fruit only was collected in October. It has not been re-collected in 30 years. We give it a preliminary conservation assessment of Critically Endangered.

DESCRIPTION Tree 10 m tall.

Twigs glabrous, with exfoliating bark; nodes with one axillary branch.

Leaves with larger blades 5.8-7.3 cm long, 3.1-3.3 cm wide, subcoriaceous, slightly discolorous, dark brown adaxially, dull reddish brown abaxially, broadly elliptic, apex acuminate, the acumen 7-10 mm long, base cuneate and long-decurrent on the petiole, margin flat, not revolute, glabrous on both surfaces; midrib concolorous with rest of blade adaxially, secondary veins weakly brochidodromous, 15-16 per side, diverging at c. 60° from midrib, these and higher-order veins raised and forming a conspicuous reticulum adaxially, but only slightly raised and less distinct abaxially; petiole 4-5 mm long, canaliculate, wrinkled, glabrous.

Inflorescences and flowers unknown.

Fruit of 4 monocarps borne on a pedicel c. 10 mm long, c. 4 mm thick, glabrous; torus c. 10 mm in diameter, c. 5 mm high, depressed-globose; monocarps with green exterior in vivo, 4.0- 4.9 cm long, 2.0- 2.3 cm wide, 1.4-1.8 cm thick, oblong to obovoid, not torulose, apex rounded, base contracted into a stipe 3-4 mm long, 4-7 mm thick, finely verrucose, strongly and obliquely wrinkled, with scattered lenticellate patches, slightly shiny, glabrous; pericarp c. 1.7 mm thick.

Seeds c. 6 per monocarp, in a single irregular row, oblique to perpendicular to long axis, c. 12 mm long, 6 mm wide, ellipsoid, wedge-shaped in cross-section, light brown, smooth, dull, perichalazal ring not evident; presence of sarcotesta undeterminable; aril absent.

NOTES

Xylopia marojejyana , sp. nov., is superficially similar to Xylopia lemurica , which occurs in nearby sites, but differs in the completely glabrous twigs with exfoliating bark and glabrous broader leaf blades with a pronounced raised vein reticulum on the adaxial surface. The monocarps differ from those of X. lemurica in being thicker, more strongly wrinkled, and having short broad stipes. It is also similar to X. humbertii , sharing the shiny subcoriaceous glabrous leaves. The type collection of X. humbertii has only flowers and that of X. marojejyana , sp. nov., only fruits, preventing more detailed comparison, but the vegetative features are sufficiently different to separate the two species.

Figures

FIG. 25. — Xylopia longirostra, sp. nov., and X. marojejyana, sp. nov. A-E, X. longirostra, sp. nov.: A, habit; B, close-up of rolled apex of developing leaf; C, immature flower bud, side view; D, monocarp, side view; E, seed, side view. F-H, X. marojejyana, sp. nov.: F, habit; G, monocarp, adaxial view; H, petiole and twig, side view. A, D, E, from Lowry et al. 6064 (OWU); B, from Razakamalala 266 (NY); C, from Andrianjafy et al. 120 (MO); F-H, based on Miller & Randrianasolo 4423 (MO). Scale bars: A, D-G, 1 cm; B, H, 2 mm; C, 1 mm.

FIG. 29. — Distributions of Xylopia galokothamna, sp. nov., X. ghesquiereana Cavaco & Keraudren, X. humbertii Ghesq. ex Cavaco & Keraudren, X. humblotiana Baill., X. kalabenonensis D.M.Johnson, Deroin, & Callmander, X. lamii Cavaco & Keraudren, X. lastelliana Baill., X. lemurica Diels, X. lokobensis, sp. nov., X. longirostra, sp. nov., X. madagascariensis Cavaco & Keraudren, and X. marojejyana, sp. nov., on Madagascar.