Xylopia dielsii Cavaco & Keraudren, 1956

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 : 56-58

publication ID	https://doi.org/ 10.5252/adansonia2020v42a1
persistent identifier	https://treatment.plazi.org/id/417D87A4-FFC4-FFD7-FF31-550C313FF8AC
treatment provided by	Tatiana
scientific name	Xylopia dielsii Cavaco & Keraudren
status

Treatment

19. Xylopia dielsii Cavaco & Keraudren View in CoL ( Fig. 21G-K View FIG )

Bulletin de la Société botanique de France 103: 277 (1956). — Type: Madagascar. Prov. Toamasina [“ Domaine de l’Est ”], forêt de Tampolo, au nord de Fénérive, XI.1953 (fl.), Capuron 8627 (holo-, P[P030383]!; iso-, OWU!, P[P030384, P030385]!, TEF[photo]!).

MATERIAL EXAMINED. — Madagascar. Prov. Toamasina. Atsinanana Region, Mahavelona/Foulpointe, Morarano, Analalava, 17°42’35”S, 49°27’02”E, 24 m, 14.II.2008 (fr.), Andriamiarinoro 124 ( OWU, P[P00847930]); Soanierana Ivongo, 27.XII.1949 (fl.), Service Forestier 2380 (P[P01986980]).

DISTRIBUTION, ECOLOGY AND CONSERVATION STATUS. — Xylopia dielsii is restricted to the coast of a small area of northeastern Madagascar ( Fig. 28 View FIG ). It seems to be yet another microendemic species of the littoral and sublittoral humid forest on sand that occurs along the eastern Madagascar coast. Specimens with flowers have been collected in November and December, and with fruits in February. Known from only three localities, and with an EOO and AOO of 461 km 2 and 12 km 2, respectively, X. dielsii is given a preliminary conservation assessment of Endangered ( Table 2 View TABLE ).

LOCAL NAME. — Hazoambo (Andriamiarinoro 124, Service Forestier 2380).

DESCRIPTION Tree up to 15 m tall.

Twigs glabrous or with a few fine hairs <0.1 mm long; nodes with one or often two axillary branches.

Leaves with larger blades 5.9-10.9 cm long, 2.8-4.3 cm wide, chartaceous, drying gray to black on both surfaces, shiny adaxially, dull abaxially, obovate, oblanceolate, or oblongobovate, apex cuspidate to acuminate, the acumen 4-6 mm long, base rounded to broadly cuneate, short-decurrent on petiole, margin flat, not revolute, glabrous on both surfaces; midrib paler toward base adaxially, secondary veins weakly brochidodromous and somewhat arcuate, 11-16 per side, diverging at 50-90° from midrib, these and higher-order veins strongly raised and forming a conspicuous reticulum on both surfaces; petiole 8-14 mm long, narrowly but deeply canaliculate, slightly wrinkled, glabrous or with a few hairs.

Inflorescences axillary, 1-2-flowered, not pedunculate, glabrous; pedicels arising separately from the axil, 5.7-10.5 mm long, 0.9-1.2 mm thick; bracts 3, one near the pedicel base, one just proximal to the pedicel midpoint, and one just distal to the pedicel midpoint, usually persistent or sometimes the lower bracts caducous, 0.8-1.7 mm long, ovate to triangular; buds linear-lanceolate, apex obtuse.

Sepals spreading at anthesis, c. ¼-connate, 1.4-1.8 mm long, 1.9-2.1 mm wide, coriaceous, semicircular, apex acute to rounded, ciliate near margin but otherwise glabrous abaxially.

Petals with color in vivo unknown; outer petals with position at anthesis unknown, 14.5-20 mm long, 2.7-3.7 mm wide at base, 1.2-1.5 mm wide at midpoint, slightly fleshy, lanceolate, flat adaxially, weakly keeled abaxially, apex obtuse, densely puberulent except for the glabrous base adaxially, densely pubescent abaxially; inner petals with position at anthesis unknown, 11.8-18.4 mm long, 1.8-2.5 mm wide at base, 0.5-0.7 mm wide at midpoint, slightly fleshy, linear, slightly keeled on apical 1/2 adaxially, slightly keeled abaxially, apex acute, base concave with undifferentiated margin, densely puberulent except for glabrous base on both surfaces.

Stamens 80-160; fertile stamens 1.1-1.3 mm long, narrowly oblong, anther connective apex c. 0.2 mm long, hemispherical, overhanging anther thecae, long-papillate, anthers 7-9-locellate, filament 0.4-0.5 mm long; outer staminodes 1.3-1.6 mm long, clavate, apex obtuse; inner staminodes sometimes with reduced anther thecae, 1.1-1.2 mm long, oblong, apex rounded to truncate; staminal cone 1.3-1.5 mm in diameter, 0.6-1.1 mm high, concealing all but the apices of the ovaries, rim irregularly laciniate.

Carpels 5-6; ovaries c. 1 mm long, oblong, densely pubescent, stigmas loosely connivent, 2.3-2.5 mm long, clavate to narrowly oblong, glabrous or with a few hairs at the tips.

Fruit of up to 7 monocarps borne on a pedicel 13-20 mm long, c. 2 mm thick, glabrous; torus c. 4.6 mm in diameter, c. 4.1 mm high, globose; monocarps with yellowish violet exterior in vivo, endocarp color unknown, 4.3-4.6 cm long, c. 1.1 cm wide, c. 0.8 cm thick, narrowly oblong, slightly falciform and torulose, apex obtuse, formed into beak 2-3 mm long, base contracted into a stipe 11-15 mm long, 3.7-4 mm thick, strongly and obliquely wrinkled, shiny, glabrate; pericarp c. 0.5 mm thick.

Seeds up to 3 per monocarp, in a single row, oblique to long axis, 8.8-11.8 mm long, c. 5.2 mm wide and thick, narrowly ellipsoid, circular in cross-section, light brown, smooth, dull, perichalazal ring not evident; presence of sarcotesta undeterminable; aril absent.

NOTES

Xylopia dielsii is a distinctive species, standing apart from others in Madagascar in its virtual lack of hairs on the vegetative parts, the long deeply canaliculate petioles, and the relatively long pedicels.

The vegetative features of Andriamiarinoro 124 accord well with the type collection, but its fruit, which is narrowly oblong and over 4 cm in length but only about 1 cm wide and glabrous, does not agree with the protologue description of the fruit of X. dielsii , which is given as “Fructus obovoideus 3 cm. longus 2 cm. latus pilosus.” A fruit of the latter description has not been found among the herbarium material of this species. Neither does the fruit of Andriamiarinoro 124 match the fruit description of X. dielsii given by Cavaco & Keraudren (1958): “Fruit volumineux, oblong-ovoïde, de 9.5 cm. de long et de 6 cm. de large, noir à l’état sec”, which seems to be based on the separate fruit collection of the paratype Capuron 8860 from “Haut bassin de la Sahafihitra (massif du Beanjada, au nord de la presqu’île Masoala) vers 800 m d’alt.” We have determined, however, that this latter specimen is an Isolona, possibly I. perrieri Diels (see Couvreur 2008).