Xylopia paniculata Exell, J. Bot. 64 (Suppl.): 8. 1926.

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 156-159

37. Xylopia paniculata Exell, J. Bot. 64 (Suppl.): 8. 1926. Fig. 35M-P

Type.

ANGOLA ["Portuguese Congo"]. Cabinda Province, Belize, Mayumbe , 22 Feb 1917, J. Gossweiler 6988 (holotype: BM! [photos GH, NY]; isotypes: COI! [00004886], LISC! [000321, 000322, 000323, 000324]) .

Description.

Tree up to 35 m tall, d.b.h. up to 36 cm, bole straight with stilt roots or small buttresses at the base, crown small; bark gray, fissured. Twigs brown, eventually light gray, initially loosely appressed-pubescent, the hairs 0.4-0.9 mm long, eventually glabrate; nodes often with two axillary branches. Leaf with larger blades 7.2-11.5 cm long, 1.8-3.7 cm wide, subcoriaceous or chartaceous, somewhat shining above, and slightly discolorous, narrowly elliptic, oblong-elliptic, lanceolate-oblong, or narrowly oblong, apex acuminate, the acumen 2-7 mm long, base broadly cuneate and short-decurrent on the petiole, glabrous or with a few hairs on the midrib adaxially, sparsely appressed-pubescent abaxially; midrib slightly impressed adaxially, raised abaxially, secondary veins strongly arcuate, indistinctly brochidodromous, 8-16 per side, diverging at 45-50° from the midrib, slightly raised on both surfaces, higher-order veins forming a fine raised reticulum adaxially, indistinct abaxially; petiole 2-3 mm long, canaliculate, pubescent. Inflorescences axillary, up to 32-flowered, spreading-pubescent; peduncles 2-3 per axil, highly branched, 1.0-4.5 mm long, sometimes with a longer floriferous axis emerging from among the cluster of flowers in an axil; pedicels 2 per ultimate peduncle branch, subtended by a basal bract 1.5-2 mm long, individual pedicels 2.2-5.7 mm long, 0.6-0.9 mm thick; bracts 1 or 2, attached at or distal to the pedicel midpoint, persistent, 1.5-3.0 mm long, ovate to broadly ovate, apex acute to rounded; flower buds lanceolate, apex acute. Sepals slightly spreading at anthesis, 1/8-1/3-connate, 2.1-3.0 mm long, 2.4-2.5 mm wide, coriaceous, ovate to semicircular, apex acute to obtuse, pubescent abaxially. Petals yellow-green to yellow, red at the base in vivo; outer petals slightly spreading at anthesis, 10-19.7 mm long, 2.3-3.6 mm wide at base, 1.0-1.7 mm wide at midpoint, slightly fleshy, linear, apex obtuse, glabrous medially in the proximal half but otherwise densely pubescent adaxially, densely pubescent abaxially; inner petals connivent at widest point of base with tips spreading at anthesis, 9.7-13.1 mm long, 2.2 -2.5 mm wide at base, 0.7-1.0 mm wide at midpoint, slightly fleshy, linear, apex acute, base with undifferentiated margin, sparsely pubescent above widest point, densely pubescent in a corrugated band across the widest point, and glabrous at the very base adaxially, densely pubescent except for the glabrous base abaxially. Stamens 120-130; fertile stamens 1-1.7 mm long, capitate, apex of connective red in vivo, 0.3-0.4 mm long, depressed-globose, overhanging anther thecae, papillate, anthers 6-9-locellate, filament 0.3-0.5 mm long; outer staminodes 1.0-1.3 mm long, clavate, apex obtuse to rounded; inner staminodes ca. 1.1 mm long, clavate, apex rounded; staminal cone 1.1-1.5 mm in diameter, 0.3-0.6 mm high, concealing the bases of the ovaries, rim laciniate. Carpels 3-6; ovaries 0.9-1.1 mm long, narrowly oblong, densely pubescent, stigmas connivent, 2.5-2.7 mm long, filiform, sparsely pubescent along entire length. Torus flat, 1.5-2.0 mm in diameter. Fruit pedicels and torus unknown. Monocarps with green exterior [silvery brown ex Letouzey] and carmine, red, or pink-red endocarp in vivo, 5.6-8.5 cm long, 3.1-4 cm wide, ca. 2.7 cm thick, oblong or obovoid, not torulose, apex rounded, base sessile, longitudinally ridged and wrinkled, transversely pleated and grainy, glabrate; pericarp ca. 3 mm thick. Seeds 3-4 per monocarp, in a single row, perpendicular to long axis, 21-21.6 mm long, 15.7-17.3 mm wide, 9.5-11.0 mm thick, flattened-ellipsoid, elliptic in cross-section, truncate at micropylar end, rounded at chalazal end, brown to black, smooth, dull, raphe/antriraphe visible as a flat band encircling the seed, micropylar scar 6-8 mm long, 4.5-6 mm wide, elliptic to circular; sarcotesta grayish blue or greenish blue, waxy in vivo; aril absent.

Phenology.

Specimens with flowers have been collected in February and from June to August, and with fruit in June.

Distribution

(Fig. 36 ). Occurs from southern Cameroon south to the Cabinda Province of Angola, in low elevation primary rainforest.

Local name.

Boëso (Bakota, Hallé & Le Thomas 379).

Additional specimens examined.

CAMEROON. East: A 23 km a l'Ouest de Masea (village situé à 50 km au SSW de Yokadouma), 4 Jul 1963 (fl), Letouzey 5402 (P-4 sheets) . GABON. Ogooué-Ivindo: 25 km SE de Mekambo 25 km SE, 7 Aug 1966 (fl), Hallé & Le Thomas 379 (P) .- Nyanga: Chantier CEB, Inventory , ca. 50 km SW of Doussala, 2°36'S, 10°35'E, 14 Jun 1985 (fl, fr), Reitsma & Reitsma 1163 (BISH, MO, NY, RSA, WAG).

Xylopia paniculata , as its specific epithet suggests, has highly branched inflorescences of up to 32 flowers, a characteristic unique among African species. It also has one of the largest monocarps of any African Xylopia species, and the largest seeds. The other species tending to have large numbers of flowers per inflorescence are X. calva , X. katangensis , X. phloiodora , and X. villosa , but all of these species have 12 flowers or fewer. In addition, X. calva has much larger leaves and broader petals, X. phloiodora usually has larger leaves with pinkish-red coloration on the secondary veins, longer petioles, longer petals, a larger and more conspicuous staminal cone, and smooth but lenticellate monocarps, and X. villosa has leaves that are densely sericeous abaxially.

Xylopia paniculata was included in Le Thomas (1969) as " Xylopia sp. B," on the basis of Hallé & Le Thomas 379, which is fragmentary although with abundant disarticulated flower material. The single leaf is at the small end of the range of variation for this species, and the petals are slightly larger than those of the other collections, but nonetheless match in qualitative features, such as the shape of the inner petals.

We calculated Xylopia paniculata to have an EOO of 105,473 km 2 and an AOO of 16 km 2, a wide disparity between the two measurements seen for several Congo Subregion lowland forest species. The most recent collection is from 1985. The label of the collection from Cameroon describes that plant as rare in ombrophilous forest of Baillonella toxisperma and Pentaclethra macrophylla .

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.