Xylopia lokobensis 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 : 72-73

28. Xylopia lokobensis D.M.Johnson & N.A.Murray , sp. nov. ( Fig. 23A-E )

In the relatively broad flowers with sepals exceeding 4 mm in length and the short obliquely oblong monocarps, Xylopia lokobensis , sp. nov., is most similar to X. capuronii , but it is distinguishable by the sparse yellowish brown indument on the twigs, leaves, and monocarps, the oblong leaf blades with flat margins, the broad leaf acumen 4-10 mm long, and the outer petals 13-19 mm long. Xylopia capuronii , in contrast, has dense dull red indument on the twigs, leaves, and monocarps, narrowly oblong to elliptic leaf blades with strongly revolute margins, a narrow leaf acumen 5-9 mm long, and outer petals 11-13 mm long.

TYPE. — Madagascar. Prov. Antsiranana, Fivondronana Nosy-Be, Lokobe Réserve intégrale , Ampasindava , 13°24’44”S, 48°18’53”E, 300 m, 7.XII.1996 (fl., fr.), Antilahimena 340 (holo-, P [ P01986965 ]!; iso-, MO!).

PARATYPES. — Madagascar. Prov. Antsiranana, Réserve naturelle intégrale No. 6 – Lokobe, south side of the reserve (“Study Site” for the Black Lemur Forestry Project), 5 km SE of Hell Ville, Nossi Be , 13°25’S, 48°18’E, 50 m, 24.XI.1992 (fl., fr.), Birkinshaw 186 ( MO n. v., OWU, P[P01986963]) ; région Diana, Ampasindava , forêt de Bongomihirahavavy, 13°45’34”S, 48°05’54”E, 400 m, 2.XII.2012 (fr.), Gautier LG 6068 (G, n. v., P[P00982774]) .

DISTRIBUTION, ECOLOGY AND CONSERVATION STATUS. — Xylopia lokobensis , sp. nov., occurs in northwestern Madagascar, on Nosy-Be island and the nearby Ampasindava peninsula, in humid forest at elevations from 50 to 400 m ( Fig. 29 ). Specimens with both flowers and fruits were collected in November and December. With an EOO value of 144 km 2 and an AOO of 8 km 2 the species is given a preliminary conservation assessment of Endangered. One of its known populations, however, lies within the protected Lokobe Reserve.

LOCAL NAMES. — Hazoabo, moranga (Antilahimena 340).

DESCRIPTION Tree up to 18 m tall; d.b.h. up to 8 cm.

Twigs densely yellowish brown-pubescent, the hairs 0.2-0.5 mm long, eventually glabrate; nodes with one axillary branch.

Leaves with larger blades 8.0- 13.4 cm long, 2.7-4.8 cm wide, subcoriaceous, discolorous, dark brown to olive-gray adaxially, brown abaxially, oblong, apex obtuse to short-acuminate, the acumen 4-10 mm long, base broadly cuneate to rounded, short-decurrent on petiole, margin flat, not revolute, glabrous except for the pubescent midrib adaxially, appressed-pubescent abaxially; midrib often darkened adaxially, secondary veins irregularly brochidodromous, 14-20 per side, diverging at 60-80° from midrib, these and higher-order veins slightly raised on both surfaces; petiole 5-10 mm long, shallowly canaliculate, smooth, pubescent.

Inflorescences axillary, 1-flowered, not pedunculate, yellowish brown-pubescent; pedicels 6-8.3 mm long, 1.2-1.4 mm thick; bracts 2, one near midpoint, one just proximal to the sepals, caducous or somewhat persistent, 3-3.8 mm long, semicircular; buds broadly lanceolate, apex obtuse, slightly falciform.

Sepals somewhat spreading at anthesis, ¼-1/3-connate, 4.2- 4.6 mm long, 5.0- 5.2 mm wide, coriaceous to slightly fleshy, broadly ovate to triangular, apex broadly acute to obtuse, pubescent abaxially.

Petals light green in bud in vivo; outer petals slightly spreading at anthesis, 13-19 mm long, 3.5-6 mm wide at base, 1.8- 3 mm wide at midpoint, fleshy, lanceolate, keeled on apical ¼ but otherwise flat adaxially, slightly keeled abaxially, apex obtuse to acute, densely puberulent except for the glabrous base adaxially, densely appressed-pubescent abaxially; inner petals probably slightly spreading at anthesis, 8.3-13 mm long, c. 2.8 mm wide at base, c. 1.3 mm wide at midpoint, slightly fleshy, lanceolate, keeled except for the concave base adaxially, keeled abaxially, apex acute to obtuse, base concave with undifferentiated margin, densely puberulent except for glabrous base on both surfaces.

Stamens and carpels not examined.

Fruit of up to 5 monocarps borne on a pedicel 9-11 mm long, 4-7 mm thick, glabrate; torus 9-17 mm in diameter, 8-10 mm high, irregularly globose; monocarps with green exterior and red endocarp in vivo, 2.4-3.0 cm long, 1.4-2.3 cm wide, 1.4- 1.6 cm thick, obliquely oblong, occasionally slightly torulose, apex rounded to obtuse, base sessile or contracted into a stipe 2-3 mm long, 4-8 mm thick, finely verrucose, obliquely wrinkled, dull, finely tomentose; pericarp 0.6-1.7 mm thick.

Seeds up to 4 per monocarp, in two rows, oblique to perpendicular to long axis, 9.5-12.6 mm long, 5.6-8 mm wide, 4.5-6.5 mm thick, oblong-ellipsoid to obovoid, wedge-shaped, broadly elliptic, or semicircular in cross-section, brown, smooth to slightly wrinkled and pitted, dull, perichalazal ring not evident; sarcotesta color in vivo not determined; aril absent.

NOTES

Xylopia lokobensis , sp. nov., belongs to the group of sect. Stenoxylopia species with clavate stigmas, and is one of several species with medium-sized leaves, moderately large flowers and subsessile oblong monocarps. The species has a tendency for the midrib and secondary veins to be darkened on the adaxial surface.Two of the three collectors of this species remarked on the strong aroma of the foliage, a characteristic not noted for other Madagascar Xylopia species. Xylopia lokobensis , sp. nov., may distinguished from X. galokothamna , sp. nov., which occurs in the same general region of Madagascar, by the tree rather than shrub habit, the leaf blade short-decurrent on a longer petiole (cf. Fig. 23A, I ), and the absence of both beak and stipe on the monocarps.

Xylopia lokobensis , sp. nov., was identified as Xylopia sp. in Birkinshaw (2001), where it was listed as a minor food source for the Black Lemur (Eulemur macaco macaco). Xylopia lokobensis , sp. nov., is one of the few large-fruited Madagascar Xylopia species for which monocarp dehiscence and red endocarp color have been documented, but color of the sarcotesta covering the seed has not been reported. The specimen Birkinshaw 186 was included in the molecular phylogenetic analysis of Stull et al. (2017), where it was one of four accessions identified as Xylopia sp. aff. fananehanensis , which, although they are recognized in this treatment as four distinct species, formed part of a single subclade in the phylogenetic analysis.

Figures

FIG. 23. — Xylopia lokobensis, sp. nov., and X. galokothamna, sp. nov. A-E, X. lokobensis, sp. nov.: A, petiole and base of leaf blade; B, leaf; C, fruit, side view; D, seed, side view; E, flower, side view. F-N, X. galokothamna, sp. nov.: F, outer petal, adaxial view; G, inner petal, adaxial view; H, habit, with fruit; I, petiole and base of leaf blade; J, outer staminode, abaxial view; K, fertile stamen,abaxial view;L, stigmas with adhering inner staminodes,side view; M, monocarp; N, seed, side view. A, D, E, from Antilahimena 340 (P); B, from Antilahimena 340 (MO); C, from Birkinshaw 186 (OWU); F, G, J, K, L, from Callmander et al. 585 (P); I, from Callmander et al. 585 (MO); H, N, from Callmander et al. 585 (OWU); M, from Buerki et al. 20 (MO). Scale bars: A, E-G, I, 5 mm; B-D, H, M, N, 1 cm; J-L, 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.