Xylopia Linnaeus, Syst. nat., ed. 10, 2: 1250 [+1378]. 1759, nom. conserv.

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 24-25

Xylopia Linnaeus, Syst. nat., ed. 10, 2: 1250 [+1378]. 1759, nom. conserv.

Xylopicrum P. Browne, Hist. Jamaic. 250-251 + t. 5, fig. 2. 1756. Xylopicron , orth. mut., Adanson, Fam. 2: 365. 1763. Type: Xylopia muricata Linnaeus, typ. conserv. (lectotype designated by Setten and Maas, Regnum Vegetabile 127: 99, 1993: Browne s. n., Herb. Linn. No. 1077.1 (LINN)).

Unona Linnaeus f., Suppl. pl. 270. Apr 1782. Bulliarda Necker, Elem. bot. 2: 321. 1790, nom. superfl., non Candolle, 1801. Type: Unona discreta Linnaeus f.

Krockeria Necker, Elem. bot. 2: 317-318. 1790. Type: Unona concolor Willdenow (lectotype, here designated).

Coelocline A. de Candolle, Mém. Soc. Phys. Genève 5: 208-209. 1832. Type: Coelocline acutiflora (Dunal) A. de Candolle.

Parartabotrys Miquel, Fl. Ned. Ind., Eerste bijv. 3: 374. 1860. Type: Parartabotrys sumatranus Miquel. Note: Name only appears as a nomen nudum in Fl. Ned. Ind., Eerste bijv. 1: 154, 1860.

Pseudanona (Baillon) Safford, J. Wash. Acad. Sci. 3: 17. 1913, as " Pseudannona ." Xylopia Section Pseudanona Baillon, Adansonia 4: 141-142. Jan. 1864. Type: Pseudanona amplexicaulis (Lamarck) Safford (lectotype, designated by Safford, J. Wash. Acad. Sci. 3: 18. 1913).

Description.

Trees up to 50 m tall with a straight bole rising to a small conical to rounded crown, with narrow buttresses or, in a few species, stilt roots at the base of the trunk, or shrubs, the branches, in a few species, lianescent; bark smooth to scaly, variable in color. Indument of simple hairs. Twigs persistently pubescent to glabrate, usually sparsely lenticellate, longitudinally wrinkled; nodes in many African species with two axillary branches. Leaf with blades chartaceous to coriaceous, lanceolate, oblong, elliptic, ovate, oblanceolate, or obovate, apex rounded to acuminate, base cuneate to rounded, sometimes decurrent on petiole, midrib impressed to slightly raised adaxially, raised abaxially, secondary veins brochidodromous to weakly brochidodromous, petiole short, usually shallowly canaliculate. Inflorescences axillary, occasionally arising from the leafless portions of branches, 1-32-flowered; peduncles 1 to several per axil or absent, pedicels 1-several per peduncle, with 1-6 small caducous to persistent bracts; buds ovoid to linear, apex obtuse to acute. Flowers bisexual. Sepals 3, usually connate at the base and forming a cuplike calyx, in a few species free and imbricate at base. Petals 6, in 2 series of three, free, white, cream-colored, pale yellow, pale orange, or, in a few species, red in vivo; outer petals erect, slightly spreading, or curved outward at anthesis, ovate to linear, flattened to a concave base adaxially, flat, often with a faint ridge, abaxially; inner petals slightly shorter and narrower (much shorter in X. rubescens ) than outer petals, ovate to linear, keeled on both surfaces but becoming concave at the base adaxially and flat at the base abaxially, often narrowed into a short claw; in a few species, the margins of the basal concavity are differentiated from the tissue of the rest of the petal. Stamens 40-200; fertile stamens clavate to oblong, apex of connective shieldlike, conical, globose, or rudimentary, often overhanging anther thecae, pubescent or papillate, rarely glabrous, anthers transversely septate, 4-24-locellate, filament much shorter than anther, articulated with the staminal cone; outer staminodes oblong to clavate, apex obtuse to obliquely truncate, rarely absent; inner staminodes often adhering to the bases of the stigmas, usually shorter than outer staminodes, clavate to oblong, apex rounded, rarely absent; filament bases connate into a staminal cone that partially or completely encloses the ovaries, the rim even or sometimes laciniate, or staminal cone absent. Carpels 2-50; ovaries oblong or ovoid, usually hairy, stigmas free or loosely connivent with tips spreading, linear, falciform, narrowly oblong, or clavate, smooth or studded with round tubercles in some species, often hairy at the apex. Torus flat or slightly concave. Fruit of up to 36 glabrate to pubescent dehiscent monocarps borne on a short woody pedicel and slightly expanded torus. Monocarps with green, red, or purple exterior and a green or pink to scarlet endocarp in vivo, linear, oblong, ovoid, or globose, often somewhat falcate, occasionally weakly torulose, apex rounded or with a curved beak or mucro, base contracted into a stipe or sessile, smooth, longitudinally ridged, finely wrinkled, or verrucose; pericarp leathery to woody when dried. Seeds up to 20 per monocarp, attached laterally in one or two rows, lying parallel, oblique, or perpendicular to long axis, oblong to ellipsoid, oblong, elliptic, or ovate in cross section, flattened at micropylar end, rounded at chalazal end, brown to black, smooth or rarely slightly pitted, dull or shiny, raphe/antiraphe forming a raised ridge encircling the seed or flat and not evident, micropylar scar elliptic to circular; seeds arillate, the aril attached around the micropyle, white, yellow, orange, red, pink, or violet in vivo, fleshy or papery, or aril absent; seed coat with a fleshy outer layer (sarcotesta) and hard inner layer, or sarcotesta absent.

A pantropical genus of ca. 180 species, in tropical Africa represented by 45 species. The only other African Annonaceae genus with elongate flower buds such as those commonly seen in Xylopia is Greenwayodendron Verdc., and the latter genus is sometimes mistaken for Xylopia on this basis; Greenwayodendron species, however, always have terminal inflorescences, which appear supra-axillary or leaf-opposed ( Verdcourt 1969). The dehiscent monocarps set Xylopia apart from all other African Annonaceae genera except the East African Mkilua Verdc. ( Verdcourt 1970) and Ophrypetalum Diels, neither of which has a brightly colored endocarp or seeds.

Patonia Wight ( Wight 1838) is usually treated as a generic synonym of Xylopia (van Setten and Maas 1990, Turner 2011). In his generic description, however, Wight explicitly described and mentioned an apical ovule and seed, and a calyx that grows up to cover the maturing fruit. These are characters of Diospyros , not of Annonaceae . We suggest that Hiern was correct in adopting the name Patonia as a synonym of Diospyros and that Patonia walkeri Wight should be its type, as the lectotype designated is in conflict with the generic protologue. Patonia parvifolia , the other species placed in the genus when it was proposed, is a Xylopia , now re-named Xylopia patoniae I. M. Turner for nomenclatural reasons ( Turner 2011).

Key to the African species of Xylopia

1	Seeds arillate, sarcotesta absent; nodes with either one or two axillary branches; staminal cone rudimentary or absent, if well developed then rim of cone even and carpels and monocarps more than 22	2
-	Seeds not arillate, but a fleshy sarcotesta present on the seed (waxy layer that scratches off); some nodes with two axillary branches; staminal cone well developed but usually with an irregular laciniate rim, carpels and monocarps never more than 22, often many fewer (sect. Stenoxylopia )	12
2	Aril white (seed unknown for X. lukei ); apex of anther connective rudimentary, not overhanging anther thecae; inner petals completely glabrous (sect. Verdcourtia )	3
-	Aril yellow, orange, red, or purple; apex of anther connective evident, overhanging anther thecae; inner petals with some hairs on both surfaces, especially toward the apex	5
3	Larger leaf blades 8.2-11.9 cm long, 4.1-5.8 cm wide	X. lukei
-	Larger leaf blades 4.6-8.7 cm long, 2.3-4.3 cm wide	4
4	Pedicels 2.4-3.5 mm long; leaf abruptly blunt-acuminate, the acumen 4-8 mm long, occasionally emarginate or obtuse; petals coriaceous to slightly fleshy	X. mwasumbii
-	Pedicels 6.7-7.2 mm long; leaf gradually acuminate, the acumen 4-11 mm long; petals membranous	X. tenuipetala
5	Aril bilobed, monocarps up to 36 per fruit; staminal cone well developed, completely enclosing the ovaries; leaf gradually long-acuminate, the acumen 6-20 mm long (sect. Xylopia )	X. aethiopica
-	Aril not bilobed, monocarps up to 15 per fruit; staminal cone absent or rudimentary in the form of a ring only covering the bases of the ovaries; leaves short-acuminate (up to 6 mm long) or, if longer, then sharply cuspidate, not gradually acuminate	6
6	Arils membranous, fimbriate, covering at least half and often the entire seed; stigmas usually discrete; inner petals with differentiated fleshy margins around basal concavity; apex of anther connective conical to capitate and papillate to long-papillate, giving a bumpy rather than flat surface to the androecium (sect. Ancistropetala )	7
-	Arils brushlike, covering only base of seed; stigmas more or less connivent; inner petals with margins undifferentiated; apex of anther connective flat or with a slight bump in the center and often pubescent, but forming a flat surface to the androecium (sect. Neoxylopia )	9
7	Leaves narrowly elliptic, acute to obtuse at the apex; pubescence of outer petals buff-brown; inner petal with a distinct truncate tooth overhanging basal concavity; stigma subequal in length to ovary; seeds 13.5-21 mm long, pointed at the chalazal end	X. aurantiiodora
-	Leaves oblanceolate to obovate, short-acuminate at the apex; pubescence of outer petals silvery to brownish gray; inner petal lacking tooth overhanging basal concavity; stigma distinctly shorter than ovary; seeds 10-12.5 mm long, rounded at chalazal end	8
8	Inflorescences usually 2-flowered, rarely up to 4, pedicels all arising independently from the axil, often recurved; outer petals chartaceous, up to 21 mm long; leaf flush white; leaf blades glabrous abaxially	X. congolensis
-	Inflorescences up to 7-flowered, some pedicels attached to a common peduncle arising from the axil; pedicels straight or sinuous; outer petals more or less fleshy, up to 13 mm long; leaf flush red to purple; leaf blades usually appressed-pubescent abaxially, sometimes glabrate	X. quintasii
9	Outer petals much longer than inner petals; monocarps strongly torulose, often moniliform	X. rubescens
-	Outer and inner petals subequal in length; monocarps torulose or not, but not moniliform (fruit of X. globosa unknown)	10
10	Leaves oblong or elliptic, widest near midpoint, 15.7-23.5 cm long, 8.3-11.7 cm wide	X. globosa
-	Leaves oblanceolate to obovate, widest distal to midpoint, 5.1-15.4 cm long, 2.0-7.9 cm wide	11
11	Sepals 2.6-3.5 mm wide; outer petals 5.8-9.6 mm long; aril usually yellow to orange in vivo; monocarps at most weakly torulose	X. staudtii
-	Sepals 4.6-5.5 mm wide; outer petals 8.2-13.5 mm long; aril blood-red in vivo; monocarps distinctly torulose	X. africana
12	Inner petals thickened and knobby on margins toward base; sarcotesta orange to red in vivo	13
-	Inner petals undifferentiated on the margins; sarcotesta orange to red or white to pale green in vivo	15
13	Leaves glabrous adaxially, veins forming a conspicuous reticulum on both surfaces; monocarps linear, glabrate, up to 22 per fruit	X. flamignii
-	Leaves pubescent adaxially, veins at most only slightly raised on either surface; monocarps oblong, sparsely pubescent, up to 10 per fruit	14
14	Sepals 2.8-4.2 mm wide; outer petals lanceolate to ovate, 6.6-11 mm long, 2.4-4.4 mm wide at midpoint; leaves usually pubescent across entire surface, rarely only along midrib adaxially	X. gilbertii
-	Sepals 1.9-2.3 mm wide; outer petals linear-lanceolate, 8.7-11.8 mm long but only 0.6-1.0 mm wide at midpoint; leaves always pubescent only along midrib adaxially	X. toussaintii
15	Leaves persistently appressed-pubescent abaxially, the hairs overlapping and forming a visible indument; seeds in two rows, oblique to perpendicular to long axis of monocarp	16
-	Leaves pubescent to glabrate abaxially, if persistently pubescent then hairs not appressed or hairs small and not overlapping; seeds in one or two rows, usually oblique to long axis of monocarp	19
16	Leaves silvery-sericeous abaxially; monocarps sessile, brown, strongly lenticellate, glabrate	X. hypolampra
-	Leaves with golden, gray, or brown pubescence abaxially; monocarps sessile or stipitate, green to brown, not lenticellate, pubescent or glabrate	17
17	Monocarps clearly stipitate, the stipes 7-24 mm long; leaf base cuneate to broadly cuneate, often oblique; flower pedicels 4.5-12 mm long	X. cupularis
-	Monocarps sessile, narrowing gradually toward base; leaf base truncate, rounded, or at most broadly cuneate, symmetrical; flower pedicels 1.4-6.9 mm long	18
18	Leaf blade truncate at base, obtuse to acute at the apex, hairs appressed but not shiny abaxially; inflorescences with up to 4 flowers	X. letestui
-	Leaf blade broadly cuneate to rounded at base, acute to acuminate at the apex, golden-sericeous abaxially; inflorescences with up to 8 flowers	X. villosa
19	Inflorescences with up to 32 flowers; seeds 15.7-17.3 mm wide	X. paniculata
-	Inflorescences with up to 10 flowers; seeds ≤ 10 mm wide	20
20	Secondary veins arcuate, diverging from the midrib at an angle of ca. 45° but continuously curving toward the apex, these and higher-order veins raised on both surfaces; rim of staminal cone even; monocarps ovoid, oblong, or broadly ellipsoid, 1.7-3.1 cm wide and thick	X. phloiodora
-	Secondary veins diverging straight from the midrib at an angle of 50-70°, these and higher-order veins plane, rarely raised and reticulate abaxially; rim of staminal cone irregularly laciniate; monocarps narrowly oblong to linear, 0.5-1.5 cm wide and thick	21
21	Most pedicels with 3-6 bracts, these often imbricate and more or less persistent, even in fruit; pedicels 1 or rarely 2 per axil	22
-	Most pedicels with 2 bracts, these often separated and with the upper persistent in flower and the lower caducous, not usually present in fruit; pedicels 1-12 per axil (some inflorescences with >1 pedicel)	30
22	Twigs covered with erect hairs uniformly 1.5-2.0 mm long	X. talbotii
-	Twigs covered with appressed hairs 0.1-0.5 mm long or with a mix of short appressed hairs and longer erect hairs up to 1.3 mm long	23
23	Hairs on twigs appressed and of uniform length, 0.1-0.5 mm long	24
-	Hairs on twigs a mix of short appressed hairs 0.1-0.4 mm long and longer erect hairs up to 1.3 mm long	26
24	Outer petals 2.2-4.1 mm wide at midpoint; seeds 12.5-14 mm long; leaf blades 9.5-17.5 cm long, 3.2-5.6 mm wide	X. mildbraedii
-	Outer petals 1.0-2.0 mm wide at midpoint; seeds 9.2-12.3 mm long; leaf blades 6-13.7 cm long, 1.8-4.7 mm wide	25
25	Outer petals 10.5-13 mm long; coastal Liberia	X. dinklagei
-	Outer petals (14.6-) 22-49 mm long; central Africa	X. thomsonii
26	Shrubs scandent on low vegetation, ultimate twigs usually thickened at the base; outer petals 24.3-73 mm long, 0.9-1.5 mm wide at midpoint; coastal Ivory Coast and Ghana	X. piratae
-	Shrubs or trees, usually upright but sometimes with lianescent branches, ultimate twigs not thickened at the base; outer petals 19.6-52 mm long, 1.0-2.5 mm wide at midpoint	27
27	Outer petals 2.2-2.5 mm wide at midpoint; beak on monocarps up to 5 mm long, narrow and curved; always treelike in habit	X. unguiculata
-	Outer petals 1-2 mm wide at midpoint; beak on monocarps broad, blunt, and up to 4 mm long or often absent; treelike or lianescent shrub habit	28
28	Monocarps with seeds in two rows, 1.1-1.5 cm wide, not torulose, stipes 3-7 mm long; Sierra Leone, Liberia, Guinea, and Ivory Coast	X. acutiflora
-	Monocarps with seeds in a single row, 0.6-1.2 cm wide, torulose, stipes 3-13 mm long; Nigeria eastward	29
29	Montane tree; monocarp stipes 8-13 mm long	X. monticola
-	Lowland lianescent shrub or small tree; monocarp stipes 3-11 mm long	X. thomsonii
30	Larger leaf blades 10-17.2 cm long, 3.6-6.5 cm wide; outer petals 2.8-5.5 mm wide at the midpoint, the adaxial surfaces glabrous except at the apex	X. calva
-	Larger leaf blades 3.6-11.4 cm long, 1.2-5.6 cm wide; outer petals 0.5-2.5 mm wide at the midpoint, the adaxial surfaces mostly pubescent	31
31	Sepals reflexed at anthesis; petals membranous to chartaceous, the apices lax and crinkled when dry; stigmas 3.8-7 mm long; flower pedicels 6.2-12 mm long; monocarps often longitudinally ridged	X. longipetala
-	Sepals erect to slightly spreading at anthesis; petals coriaceous to fleshy, the apices rigid or bent outward when dry; stigmas 1.3-4.4 mm long; flower pedicels 2.8-8.2 mm long; monocarps sometimes obliquely wrinkled but not longitudinally ridged	32
32	Adaxial surface of leaf blades uniformly pubescent to sparsely pubescent, the hairs sometimes denser along the midrib	33
-	Adaxial surface of leaf blades completely glabrous or with hairs confined to the midrib	39
33	Shrubs; outer petals erect, inner petals sharply bent outward at the base at anthesis; endocarp of mature monocarp pink to red	34
-	Small to large trees; outer and inner petals both curved outward from the base, the apices incurved at anthesis; endocarp of mature monocarp green (white, possibly immature, in X. holtzii )	35
34	Hairs on twigs erect, 1-2 mm long, flowers red, monocarps glabrous and somewhat pruinose	X. collina
-	Hairs on twigs matted and twisted, 0.2-0.6 mm long, flowers white to cream-colored, monocarps pubescent, not pruinose	X. tomentosa
35	Most leaves relatively narrow, the larger blades 6.1-11.4 cm long, 1.5-4.4 mm wide; some inflorescences usually branched, (2-) 3 or more flowers in an inflorescence; monocarps either uniformly pubescent or strongly verrucose	36
-	Most leaves relatively broad, the larger blades 3.3-10.2 cm long, 1.7-5.1 cm wide; inflorescences rarely branched, 1-2 (-6)-flowered, the flowers usually arising from the same axil on separate pedicels; monocarps sparsely pubescent to glabrate, smooth to minutely verrucose	37
36	Higher-order veins less prominently raised than the secondary veins, forming only a faint reticulum on the adaxial surface; larger leaf blades 7.4-11.4 cm long; monocarps obliquely wrinkled and minutely verrucose (visible with hand lens), stipe 3-3.5 mm thick at the midpoint; coastal Kenya and Tanzania	X. holtzii
-	Higher-order veins equal in prominence to the secondary veins, forming a conspicuous raised reticulum on the adaxial surface; larger leaf blades 6.5-9.2 cm long; monocarps conspicuously verrucose but not much wrinkled, stipe 3.5-5 mm thick at the midpoint; Sudan to Uganda	X. nilotica
37	Flower buds abruptly narrowed 3-4 mm above the base and then tapering to apex; outer petals usually 21-30 mm long, rarely shorter, and 3.4-3.9 mm wide at the base; monocarps strongly rugose, short-stipitate, 2.5-7 mm long, or sessile	X. odoratissima
-	Flower buds tapering gradually to apex; outer petals at most 21 mm long, usually shorter, and 2.3-3.3 mm wide at base; monocarps obliquely finely wrinkled, distinctly stipitate, the stipe 3.5-11 mm long	38
38	Base of leaf blade broadly cuneate, occasionally cuneate or rounded; flower pedicels slender, 0.3-1 mm thick	X. gracilipes
-	Base of leaf blades rounded, occasionally broadly cuneate, truncate, or subcordate; flower pedicels 1.2-1.5 mm thick	X. shirensis
39	Pedicel of flower 8.5-21.5 mm long; leaves acuminate to caudate, the acumen 5-16 mm long, rounded at the tip; secondary veins 15-22 per side	X. wilwerthii
-	Pedicel of flower 0.4-9.1 mm long; leaf apex rounded, emarginate, obtuse, or acute, if acuminate the acumen either sharp-pointed or less than 11 mm long; secondary veins 7-14 (-17) per side	40
40	Leaf blades glabrous or only with a few scattered hairs abaxially; inflorescences (1-) 2-12-flowered, with all pedicels usually branching from a single peduncle	X. katangensis
-	Leaf blades with a sparse to dense but uniform covering of hairs abaxially; inflorescences 1-8-flowered, pedicels arising separately from the axils or sometimes with multiple peduncles from the same axil	41
41	Monocarps sessile, with pink to red endocarp; seeds in two rows, with orange sarcotesta; bracts on flower pedicel 2, both attached distal to midpoint of pedicel	X. keniensis
-	Monocarps stipitate, the stipe 1.5-11 mm long, endocarp pink to red or green; seeds in one or two rows, with pale gray to green or orange sarcotesta; bracts on flower pedicel 2-4, attached at various points but at least one attached proximal to midpoint of pedicel (may be caducous but scar will be present)	42
42	Monocarps oblong to ovoid, not torulose, 2.6-5.4 cm long, 1.3-2.0 cm wide and thick	43
-	Monocarps narrowly oblong, sometimes slightly torulose, 1.6-5 cm long, 0.5-1.4 cm wide and thick	44
43	Upper bark red, rough, and scaly; outer petals 15.2-20.5 cm long; petiole 1-2.5 mm long	X. pynaertii
-	Upper bark light gray, finely fissured or scaly; outer petals 28-38 mm long; petiole 2-4 mm long	X. tanganyikensis
44	Some inflorescences with flowers branching from a common peduncle, (1-) 2-8-flowered; monocarps either uniformly pubescent or strongly verrucose	45
-	Inflorescences with the flowers arising from the same axil on separate pedicels, seldom branching from a common peduncle, 1-2-, rarely 4-flowered; monocarps with irregular patches of sparse pubescence or glabrate, smooth to minutely verrucose	47
45	Shrub or sub-shrub 0.4-4 m tall; larger leaf blades 2.5-6 cm long	X. tomentosa
-	Tree up to 25 m tall; larger leaf blades 6.5-11.4 cm long	46
46	Higher-order veins less prominently raised than the secondary veins, forming only a faint reticulum on the adaxial surface; larger leaf blades 7.4-11.4 cm long; monocarps obliquely wrinkled and minutely verrucose (visible with hand lens), stipe 3-3.5 mm thick at the midpoint; coastal Kenya and Tanzania	X. holtzii
-	Higher-order veins equal in prominence to the secondary veins, forming a conspicuous raised reticulum on the adaxial surface; larger leaf blades 6.5-9.2 cm long; monocarps conspicuously verrucose but not much wrinkled, stipe 3.5-5 mm thick at the midpoint; Sudan to Uganda	X. nilotica
47	Twigs densely erect-hairy; seeds in two rows and perpendicular to long axis of monocarp; riparian forests from Sierra Leone to the Central African Republic	X. elliotii
-	Twigs sparsely lax- or appressed-pubescent; seeds in a single row and oblique to long axis of monocarp; forests and open country of eastern and southern Africa	48
48	Flower buds ovoid-conic; outer petals 6.6-10.2 mm long, inner petals 4.7-7.2 mm long; endocarp pink to scarlet	X. arenaria
-	Flower buds linear-lanceolate to linear; outer petals 9.5-30.4 mm long, inner petals 6.1-15.3 mm long; endocarp green	49
49	Pubescence of younger shoots consisting of straight, erect to appressed hairs; petals chartaceous, linear-filiform; monocarps 2.8-3.1 cm long; southern Mozambique in sandy habitats near the coast	X. torrei
-	Pubescence of younger shoots consisting of kinked, bent, and twisted hairs; petals coriaceous, linear-subulate; monocarps 2.8-5.0 cm long; widespread species of southern Tanzania, Mozambique, eastern Zimbabwe, and northeastern South Africa	X. gracilipes