Xylopia calva D. M. Johnson & N. A. Murray, 2018

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 125-128

27. Xylopia calva D. M. Johnson & N. A. Murray sp. nov. Fig. 35Q-T

Diagnosis.

Species resembling Xylopia phloiodora in the short branched inflorescences and large ellipsoid fruits, but differing in the much broader oblong-lanceolate petals that are glabrous adaxially except for a fringe of hairs on the apices, the leaves sometimes glaucous abaxially, the staminal cone smaller and the rim laciniate, the anthers only 10-13-locellate, and the lack of pronounced reticulum on the adaxial surface of the leaf.

Type.

CAMEROON. South Region, Bipinde, 1903 (fl), G. A. Zenker 4747 (holotype: BM [000511011]; isotypes: G! K! L! [0191105], M! MO! [751089]) .

Description.

Tree of unknown height, d.b.h. 30 cm, bole straight, cylindrical, slender, with buttresses reaching a height of 1 m from the base; bark pinkish gray with white flecks, smooth. Twigs dark brown to gray, pubescent, the hairs 0.3-0.4 mm long, soon glabrate; nodes occasionally with two axillary branches. Leaf with larger blades 10-17.2 cm long, 3.6-6.5 cm wide, chartaceous to subcoriaceous, concolorous but sometimes slightly glaucous abaxially, elliptic to elliptic-oblong, apex acuminate, the acumen (3-) 9-21 mm long, base broadly cuneate to rounded and short-decurrent on the petiole, with a few hairs along the midrib adaxially, sparsely appressed-pubescent abaxially; midrib plane to slightly impressed adaxially, raised abaxially, secondary veins irregularly brochidodromous, 8-15 per side, diverging at 50-65° from the midrib, these and higher-order veins slightly raised on both surfaces; petiole 3-10 mm long, shallowly canaliculate, sparsely pubescent. Inflorescences axillary, 1-10-flowered, rusty-pubescent; peduncle 1 per axil, 1-3 mm long; pedicels 1-10 per peduncle, 5-8 mm long, 1.3-1.5 mm thick; bracts 1-2, evenly spaced on pedicel, the lower caducous and the upper persistent, 2-3 mm long, broadly ovate to semicircular, apex obtuse to acute; buds lanceolate, apex obtuse. Sepals slightly spreading at anthesis, 1/4-1/3 connate, 3.8-4.5 mm long, 4.4-5.1 mm wide, coriaceous, broadly ovate, apex acute to obtuse, densely rusty-pubescent abaxially. Petals pale yellow, inner petals reddish at the base adaxially in vivo; outer petals probably slightly spreading at anthesis, 13-23 mm long, 3.8-6 mm wide at base, 2.8-5.5 mm wide at midpoint, fleshy, oblong-lanceolate, apex obtuse, densely puberulent only on trigonous apex adaxially, appressed-pubescent except for a glabrous patch at the base abaxially; inner petals probably slightly spreading at anthesis, 10-17.5 mm long, 2.5-4 mm wide, 2.2-3.0 mm wide at midpoint, fleshy, oblong-lanceolate, apex acute, base with undifferentiated margin, puberulent at apex but otherwise glabrous adaxially and uniformly puberulent except for the glabrous base abaxially. Stamens ca. 200; fertile stamens 1.4-2.2 mm long, narrowly oblong, apex of connective red in vivo, 0.1-0.3 mm long, dome-shaped to shieldlike, overhanging the anther thecae, papillate, anthers 10-13-locellate, filament 0.7-0.8 mm long; outer staminodes 2.1-2.8 mm long, clavate to oblong, apex obtuse, rounded, or truncate; inner staminodes 1.1-1.2 mm long, oblong, apex truncate; staminal cone 1.6-2.5 mm in diameter, 0.9-1 mm high, partially concealing the ovaries, rim laciniate. Carpels ca. 9; ovaries ca. 1.8 mm long, narrowly oblong, pubescent, stigmas connivent at the base, ca. 2.2 mm long, linear but thickened in the middle, with a tuft of hairs at the apex. Torus flat, 2.5-3.5 mm in diameter. Fruit of up to 8 pubescent monocarps borne on a pedicel 6-6.8 mm long, 2.4-2.5 mm thick, rusty-pubescent; torus 5.8-6 mm in diameter, 3-4.5 mm high, depressed-globose. Monocarps ca. 3.2 cm long, ca. 1.7 cm wide and thick, ellipsoid, not torulose, apex obtuse, base narrowed, contracted into a stipe ca. 3 mm long, ca. 7 mm thick, longitudinally wrinkled, with strips of rusty pubescence; pericarp ca. 2.5 mm thick. Seeds 7-8 per monocarp, in two rows, lying perpendicular to long axis, ca. 9.3 mm long, 6.5-6.8 mm wide, 4.5-6.1 mm thick, oblong, elliptic in cross-section, truncate at micropylar end, rounded at chalazal end, brown, smooth or slightly wrinkled, dull, raphe/antiraphe faintly evident, micropylar scar not observed; sarcotesta in vivo unknown; aril absent.

Phenology.

Specimens with flowers were collected in April, and with young fruits in May.

Distribution

(Fig. 36 ). Known from three localities, two of them in southwestern Cameroon and the other in south-central Nigeria, from low elevation forest.

Local name.

Ohun (Ross R.202).

Additional specimens examined.

NIGERIA. Edo State, Okomu Reserve, near U. A. C. timber camp, Onikaroga , 12 May 1934 (yg fr), Ross R. 202 (K) . CAMEROON. Près des chutes du Ntem ou de Menve’ele près Nyabessan (60 km E de Campo), 8 Apr 1970 (fl), Letouzey 10306 (P) .

Xylopia calva is distinguished by its long broad petals that are glabrous adaxially (L. Xylopia calva , “bald”) except at the apices. It is most similar to X. phloiodora , having the same pedunculate and branched inflorescence found in that species, but may be distinguished by the glaucous tinge to the abaxial surface of the leaves, straight rather than arcuate secondary veins, indistinct higher-order venation, outer petals 2.8-5.5 mm wide at the midpoint, anthers only 10-13-locellate, and laciniate rim of the staminal cone. The only fruit seen was not fully mature.

The type specimen was initially identified as Xylopia aethiopica and filed in herbaria under that name. The other two specimens were only identified as " Xylopia sp." The specimen Ross R.202 is labeled as having been seen for the second edition of Flora of West Tropical Africa ( Keay 1954-1958), but there is no mention of this specimen in the Xylopia treatment of that work. We calculated an EOO of 22,406 km 2 and an AOO of 12 km 2 for this species; the fact that there are only three collections, the most recent one from 1970, suggests that the species should be of conservation concern.

Figures

Figure 35. Xylopia phloiodora, X. paniculata, and X. calva. A-L X. phloiodora A Opening flower, lateral view B Old floral receptacle, showing staminal cone C Leaf, narrow extreme D Habit E Expanding vegetative shoot F, G Stamens, abaxial view to show size variation H Outer petal, adaxial view I Inner petal, adaxial view J Fruit K Seed, view from micropylar end L Seed, lateral view M-P X. paniculata M Inflorescence N Flower with petals and stamens removed, to show staminal cone O Inner petal, adaxial view P Outer petal, adaxial view Q-T X. calva Q Inflorescence R Flower with stamens and petals removed, to show staminal cone S Inner petal, adaxial view T Outer petal, adaxial view. A, B, D, F-I from Louis 13430 (US) C from Louis 7220 (WAG) E from Tisserant 1113 (BM) J from Tisserant 1138 (P) K, L from Fay and Harris 1138 (MO) M-P from Reitsma & Reitsma 1163 (NY) Q-T from Letouzey 10306 (P).

Figure 36. Distributions of Xylopia phloiodora, X. paniculata, and X. calva. Bolder lines represent country borders, fainter lines lakes and major rivers.