Xylopia kalabenonensis D.M.Johnson, Deroin & Callmander

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 : 65-66

24. Xylopia kalabenonensis D.M.Johnson, Deroin & Callmander ( Figs 1E ; 16H )

Candollea 64 (2): 183-187 (2009). — Type: Madagascar. Prov. Antsiranana, Préfecture d’Ambilobe, commune de Beramanja, Anketrabe, forêt de Kalabenono, chaîne du Galoka, 7 km au SE d’Anketrabe, 13°38’23”S, 48°40’06”E, 854 m, 18.XI.2006 (fl., fr.), Razafitsalama et al. 1041 (holo-, MO!; iso-, G!, OWU!, P n. v.).

DISTRIBUTION, ECOLOGY AND CONSERVATION STATUS. — Xylopia kalabenonensis is only known on the rocky sandstone areas of the Kalabenono massif of northern Madagascar, where it occurs in subhumid to humid forest at c. 850 m. The single specimen, with both flowers and fruits, was collected in November. The previous

conservation assessment of Critically Endangered, based on its AOO of only 9 km 2 encompassing a single known population occurring outside any protected area ( Callmander et al. 2009), has not changed.

DESCRIPTION Shrub 6 m tall; d.b.h. 8 cm.

Twigs densely hispid, with persistent pale brown hairs 1.2-2 mm long; nodes with one or occasionally two axillary branches.

Leaves with larger blades 8.4-9.0 cm long, 2.8-2.9 cm wide, subcoriaceous, discolorous, greenish gray adaxially, light brown abaxially, oblong, apex acuminate, the acumen 6-8 mm long, base rounded, not decurrent, margin slightly revolute, glabrous except for dense erect hairs on the midrib adaxially, erect-hairy abaxially; midrib darker than blade adaxially, secondary veins irregularly brochidodromous, 12-13 per side, diverging at 70-90° from midrib, these and higher-order veins indistinct adaxially, raised and conspicuous abaxially; petiole 3-4 mm long, semi-terete, smooth, densely hispid.

Inflorescences axillary, 1-flowered, not pedunculate, densely hispid; pedicels 7-7.5 mm long, 1.2-1.3 mm thick; bract 1, attached distal to the midpoint, persistent, 3-3.6 mm long, triangular to ovate; buds oblong, apex obtuse.

Sepals slightly spreading at anthesis, 1/2-connate, 4.0- 4.5 mm long, 4.0- 4.7 mm wide, coriaceous, ovate, apex acute, hispid abaxially.

Petals white to cream-colored in vivo; outer petals spreading at anthesis, 11.5-13 mm long, 3.5-4.5 mm wide at the base, 3.3-4 mm wide at midpoint, fleshy, lanceolate-oblong, weakly keeled on apical ¼ adaxially, flat abaxially, apex obtuse, densely puberulent except for the glabrous base adaxially, densely silvery sericeous abaxially; inner petals erect at anthesis, 8-10.1 mm long, 3.3-3.4 mm wide at base, 1.9-2.0 mm wide at midpoint, fleshy, lanceolate, weakly keeled on apical 1/3 adaxially, keeled abaxially, apex acute, base shallowly concave with undifferentiated margin, sparsely puberulent but becoming glabrous toward the base adaxially, pubescent except for the glabrous base abaxially.

Stamens c. 300; fertile stamens c. 2 mm long, clavate to narrowly oblong, anther connective apex 0.2-0.3 mm long, hemispherical, overhanging anther thecae, papillate or with a few hairs, anthers 11-14-locellate, filament 0.4-0.5 mm long; outer staminodes 2-2.2 mm long, clavate to narrowly oblong, apex obtuse; inner staminodes 1.2-1.4 mm long, oblong to clavate, apex obtuse; staminal cone 2.4-2.8 mm in diameter, 1.4-2 mm high, concealing all but the apices of the ovaries, rim irregularly laciniate.

Carpels c. 8; ovaries 1-1.4 mm long, narrowly oblong, sparsely pilose, stigmas connivent, 3.2-3.3 mm long, clavate, pilose at the apices.

Fruit of up to 5 monocarps borne on a pedicel 5-7 mm long, c. 3.5 mm thick, pubescent; torus 5-6 mm in diameter, c. 5 mm high, short-cylindrical; monocarps with red exterior in vivo, 3-3.5 cm long, 1.5-2 cm wide, 1.8-2 cm thick, oblong, slightly torulose, apex rounded to obtuse, base sessile, faintly wrinkled, slightly shiny, hispid; pericarp c. 0.4 mm thick.

Seeds [ex Callmander et al. 2009] up to 5 per monocarp, in two rows, oblique to long axis, 7-7.6 mm long, 4.3-4.8 mm wide, 3.8-4.1 mm thick, ellipsoid, elliptic to somewhat wedge-shaped in cross-section, light brown, smooth, dull, perichalazal ring not evident; presence of sarcotesta undeterminable; aril absent.

NOTES

Xylopia kalabenonensis belongs to the group of Madagascar species with clavate stigmas and relatively broad petals. It resembles Xylopia capuronii in its densely pubescent twigs and pedicels, but the hairs are pale brown and straight instead of dull red and twisted. The leaf blades are only slightly revolute rather than strongly revolute, and the outer petals are longer and narrower. The petal orientation at anthesis, with the outer petals wide spreading and the inner petals erect, is similar to that of X. australis , sp. nov., which is also a member of the species group within sect. Stenoxylopia with clavata stigmas. As noted in Callmander et al. (2009), another specimen collected from the same mountain (Razafitsalama et al. 1055 (MO, OWU), Ambilobe, Beramanja, Anketrabe, forêt de Kalabenono, sur la chaine Galoko, 7 km au Sud-Est d’Anketrabe, 13°88’23”S, 48°40’06”E, 854 m, 18.XI.2006) differs in several ways from the new species: the indument is shorter (hairs 0.5-0.9 mm long) and more lax, the leaf is lanceolate, cuneate at the base, slightly longer, and has flat rather than revolute margins, the inflorescences are sometimes 2-flowered, with slightly shorter (3-5 mm) pedicels, and the staminal cone is smaller (1.7 mm in diameter). As this specimen lacks mature flowers or fruits, additional material will be needed to determine its status.

Figures

FIG. 1. — Aspects of Xylopia L. vegetative and floral morphology: A, shrub habit of X. humblotiana Baill.; B, habit of X. bemarivensis Diels, showing several nodes with both collateral buds forming shoots, creating pseudo-opposite branches; C, flowers of X. lastelliana Baill., showing inner petals bent outward through the gaps between outer petals (Schatz & Modeste 2877); D, flowers of X.perrieri Diels showing conspicuous red coloration at the bases of the outer petals (Schatz & O’Connor 2964); E, spreading outer petals and erect inner petals of X. kalabenonensis D.M.Johnson, Deroin, & Callmander (Razafitsalama et al. 1041); F, flower of X. richardii Boivin ex Baill., with stigmas emerging in the center amidst the inner petals; G, inflorescences of X. beananensis Cavaco & Keraudren, showing a bud, two flowers with petals, stamens, and stigmas fallen so that the staminal cone is visible, and one open flower (Buerki 14); H, open flower of X. lamarckii Baill.; I, open flower of X. lamarckii with one outer petal and one inner petal removed to show interior of flower, including stamens and stigmas. Photos: A, M. C. Andriamahay; B, F. Rakotoarison; C, D, G. E. Schatz; E, J. Razafitsalama; F, H, I, C. Kaiser-Bunbury; G, M. W. Callmander. A, B, used under the terms of the Creative Commons license for iNaturalist; C-E, G, used under the terms of the Creative Commons license for Tropicos, the botanical information system at the Missouri Botanical Garden.

FIG. 16. — A, Fruit of X. australis, sp. nov. (Rakotovao 4575); B, flower of X. bemarivensis Diels (Nusbaumer 8139); C, flower bud of X. galokothamna, sp. nov. (Ratovoson 2065); D, fruit of X. galokothamna, sp. nov. (Ratovoson 2065); E, fruit of plant resembling X. galokothamna, sp. nov., but with different pericarp pattern (see text) (Buerki 20); F, monocarps and leafy shoots of X. lastelliana Baill. (Rakotovao 4603); G, flowers of X. australis, sp. nov. (Schatz 2641); H, monocarps of X. kalabenonensis D.M.Johnson, Deroin, & Callmander (Razafitsalama et al. 1041). Photos: A, F, C. Rakotovao; B, L. Nusbaumer; C, D, F. Ratovoson; E, M. W. Callmander; G, G. E. Schatz; H, J. Razafitsalama. A, C-H, used under the terms of the Creative Commons license for Tropicos, the botanical information system at the Missouri Botanical Garden; B, L. Nusbaumer (© Conservatoire et Jardin botaniques de la Ville de Genève).