Xylopia acutiflora (Dunal) A. Richard, Hist. phys. Cuba, Pl. vasc. 1: 55. 1841 [ "1845" ].

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 122-124

26. Xylopia acutiflora (Dunal) A. Richard, Hist. phys. Cuba, Pl. vasc. 1: 55. 1841 [ "1845"]. Fig. 33E-G

Unona acutiflora Dunal, Monogr. Anonac. 98, 116, t. 22. Aug-Nov 1817.

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

Xylopicrum acutiflorum (Dunal) Kuntze, Revis. gen. pl. 1: 8. 1891. Type. SIERRA LEONE ["Hab. in Americâ meridionali"]. Without definite locality, H. Smeathman s. n. (holotype: G-DC! [00201442]; isotypes: BM! [000510953, 000510954, 000511060, right-hand side of sheet], FI [004821]).

Unona oxypetala Candolle ex Dunal, Monogr. Anonac., Aug-Nov 1817.

Coelocline ? Xylopia oxypetala (Candolle ex Dunal) A. de Candolle, Mém. Soc. Phys. Genève 5: 209. 1832.

Xylopia oxypetala (Candolle ex Dunal) Engler & Diels, Monogr. afrik. Pflanzen-Fam. 6: 63. 1901. Type. SIERRA LEONE. Without definite locality, A. Afzelius s. n. (lectotype: B! [100249555], as to the material with flowers; isotypes: BM! [000511060, left-hand side of sheet], FI! [005602]).

Description.

Tree up to 15 m tall, d.b.h. up to 15 cm; bark smooth, pale brown to gray-brown. Twigs brown, pubescent, with erect hairs 0.7-1.5 mm long mixed with shorter (0.2-0.3 mm) hairs, eventually light gray to gray-brown, glabrate; nodes occasionally with two axillary branches. Leaf with larger blades 5.3-11.7 cm long, 2.3-4.3 cm wide, chartaceous, concolorous to slightly discolorous, elliptic to elliptic-lanceolate, apex acute to acuminate, the acumen (2.5-) 5-11 mm long, base cuneate to broadly cuneate, sparsely pubescent on the midrib but otherwise glabrous adaxially, sparsely appressed-pubescent with longer hairs on the midrib and margin to glabrate abaxially; midrib plane to slightly impressed adaxially, raised abaxially, secondary veins weakly brochidodromous, 9-14 per side, diverging at 60-70° from the midrib, these and higher order veins slightly raised adaxially, raised and forming a reticulum abaxially; petiole 3.2-5 mm long, canaliculate, pubescent to glabrate. Inflorescences axillary, 1-flowered, pubescent; pedicels 3.0-5.5 mm long, 1.2-1.5 mm thick; bracts imbricate on proximal half of pedicel, 3-6, persistent, 1.6-2.6 mm long, obovate, ovate, or orbicular, apex rounded and sometimes apiculate; buds linear-lanceolate, slightly falciform, apex acute to obtuse. Sepals slightly spreading to spreading at anthesis, 1/5-1/4-connate, 2.2-3.7 mm long, ca. 3 mm wide, coriaceous to fleshy, ovate to triangular, apex acute to occasionally acuminate, sericeous abaxially. Petals white to pale yellow, with a patch of red at the base in vivo; outer petals erect to somewhat spreading at anthesis, 19.6-37 mm long, (2.3-) 3.0-3.3 mm wide at base, 1.6-2.0 mm wide at midpoint, coriaceous, linear, apex obtuse, longitudinally ridged abaxially, puberulent but becoming glabrous in the basal third adaxially, sericeous abaxially; inner petals somewhat spreading at anthesis, 16-33 mm long, 2.4-3.2 mm wide at base, 1-1.2 mm wide at midpoint, coriaceous, linear, apex acute, base with undifferentiated margin, longitudinally ridged on both surfaces, pubescent on both surfaces except for the glabrous base. Stamens numerous; fertile stamens 1.4-1.6 mm long, narrowly oblong to clavate, apex of connective red in vivo, 0.2-0.3 mm long, shieldlike, glabrous, anthers 9-12-locellate, filament 0.4-0.5 mm long; outer staminodes 1.5-1.6 mm long, clavate to narrowly oblong, apex rounded to truncate; inner staminodes 0.9-1.1 mm long, rectangular, apex truncate; staminal cone 1.8-2.2 mm in diameter, 1.0-1.6 mm high, concealing lower half of the ovaries, rim laciniate. Carpels 7-13; ovaries ca. 1.2 mm long, oblong, densely pubescent, stigmas connivent, 2.7-3.0 mm long, filiform, glabrous except for an apical tuft of hairs. Torus concave beneath ovaries but otherwise flat, 1.8-2.5 mm in diameter. Fruit of up to 10 glabrate monocarps borne on a pedicel 5-9 mm long, 2.3-5.6 mm thick, sparsely pubescent to glabrate, often with short dead branch attached and bracts and sepals persistent; torus 5.9-11.5 mm in diameter, 4.2-7.5 mm high, depressed-globose, sunken where monocarps attached. Monocarps with a green, sometimes reddish-tinged, exterior and a scarlet endocarp in vivo, 2.5-5.1 cm long, 1.1-1.5 cm wide, 1.2-1.3 cm thick, oblong, sometimes weakly torulose, apex obtuse or with an oblique truncate beak 1.5-2 mm long, base contracted into a stipe 3-7 mm long, 2.9-4.5 mm thick, longitudinally ridged or wrinkled, verrucose; pericarp 0.7-1.2 mm thick. Seeds up to 20 per monocarp, in two rows, lying perpendicular to long axis, 11-12 mm long, 6.5-7.9 mm wide, 5.8-5.9 mm thick, ovoid to ellipsoid, wedge-shaped in cross-section, truncate at micropylar end, rounded at chalazal end, brown, smooth, dull, raphe/antiraphe not evident, micropylar scar ca. 3.5 mm long, ca. 1.5 mm wide, oblong-ovate; sarcotesta color unknown in vivo, forming a waxy crust on dried seeds; aril absent.

Phenology.

Specimens with flowers have been collected from February to June and in September, and with fruits in February and from August to October.

Distribution

(Fig. 34 ). Occurs in Sierra Leone, Guinea, Liberia, and Ivory Coast, in both primary and secondary forests at low to middle elevations.

Local names.

Elo blanc ( Aubréville 90), gbaa (Yallah 51).

Additional specimens examined.

GUINEA. Environs de Forecariah , bosquet de Kankan nara, Jun 1937 (fl), Jacques-Félix 1715 (P) . SIERRA LEONE. Kabala, Mt. Loma, Seisikoro , 6 Dec 1965 (st), Adam 22396 (MO); Falaba, 2 Apr 1914 (fl), Aylmer 29 (MO); Gola Forest , 25 Apr 1952 (buds), Small 639 (B, MO); Gola Forest , 14 May 1952 (fl), Small 664 (MO) . LIBERIA. Yekepa, Mt. Nimba, 13 Oct 1969 (st), Adam 24221 (MO); Yèkèpa, Yekepa , Mt. Nimba ( Mt. Yuelliton ), 25 May 1970 (fl), Adam 25678 (K, MO); Yekepa , Mt. Nimba ( Mt. Gangra ), 21 Oct 1971 (fr), Adam 26395 (MO, P); Yekepa , Nimba, New Camp Grassfield , 14 May 1973 (fl), Adam 27551 (MO, P, PRE, WAG); Eastern Province , Tchien District , Ziah Town [ “Zeahtown”], 1 Aug 1947 (fr), Baldwin 6970 (K, MO); Monserrado Co., Bomi Hills, 3 Feb 1950 (fl), Baldwin 14086 (K, MO, NY, US); Gola-Yoma National Forest , Bomi Hills, 6 Feb 1966 (fl), van Meer 390 (MO, WAG); Nimba area, 10 Apr 1962 (fl), Voorhoeve 1089 (B, M, MO, WAG-2 sheets); Gola National Forest , ca. 15 km NE of Bomi Hills, 17 Apr 1962 (fl), de Wilde & Voorhoeve 3833 (A, B, BR, K, P, WAG-3 sheets); Mt. Bele , 16 Apr 1965 (fl), Yallah 51 (K, P) . IVORY COAST. Taï ( Aubréville 1959), without definite locality, 9 Feb 1957 (fr), Aubréville 90 (P-3 sheets); 10 km ESE of Taï, 05°50'N, 07°22'W, 6 Sep 1975 (fl, fr), Beentje 879 (WAG-2 sheets); vicinibus oppidi Tienkulà, ad occidentem reipublicae, 1 Mar 1962 (fl), Bernardi 8315 (A, G-2 sheets, K, M, MO, US-2 sheets); 80 km S of Soubré, 3 Apr 1968 (fl), Geerling & Bokdam 2478 (K, MO, WAG-2 sheets); Taï, 11 Sep 1975 (fl, fr), de Koning 5996 (MO, WAG-2 sheets); Guiglo, Taï, 05°52'N, 7°27'W, 1 Mar 1982 (fl), Stäuble NS 0460 (MO) .

Xylopia acutiflora is one of six species belonging to a geographically widespread complex of species that vary in habit, indument, and flower and fruit morphology, but all formerly considered as representing a single species. Xylopia acutiflora s. s. is a small tree, with a mix of short and long hairs on the twigs, petals reaching 37 mm in length, and short broad monocarps with two rows of seeds. It is restricted to a relatively small area of West Africa in lowland and lower montane forests. It overlaps in Liberia with X. dinklagei , but that species is a shrub or liana with uniform short hairs on the twigs, petals reaching only 13 mm in length, and longer and narrower monocarps with a single row of seeds. Xylopia piratae from the Ivory Coast and Ghana likewise differs in being a liana with narrow monocarps, but has variable twig indument like X. acutiflora and much longer petals, reaching 73 mm in length.

Information about Xylopia acutiflora pertaining to plants from areas east of Ivory Coast probably applies to other species. In most cases, these refer to segregate species of the larger X. acutiflora complex, but the report of X. acutiflora for the Flora Zambesiaca area ( Robson 1960) is based on the specimen Holmes H.1273 (K), which is not a member of this group at all. It is most similar to X. elliotii and is discussed under that species.

The ecology of X. acutiflora is largely unknown. In Taï National Park in western Ivory Coast, the seeds of Xylopia acutiflora were eaten and spat out by the monkey, Colobus polykomo , which fed on the seeds of other Xylopia species as well ( Koné et al. 2008). A new rust species, Sphaerophragmium xylopiae Beenken & R. Berndt, was recently described from teliospores found attached to the specimen Bernardi 8315 ( Beenken and Berndt 2010). This rust genus seems to be confined to Fabaceae and Annonaceae .

Historically, there has been confusion over the application of the name Xylopia acutiflora . Bentham (1862) accepted three African species of Xylopia , X. aethiopica , X. acutiflora , and X. parviflora , the latter being a new combination based on the Uvaria parviflora Rich. Bentham expressed doubt, however, about the distinctness of the latter two species, and even whether the plant described as Unona oxypetala Dun. was distinct from them. The specimens cited by Bentham under both X. acutiflora (Barter from the confluence of the Quorra and Chadda Rivers, Chr. Smith from the Congo) and X. parviflora (Vogel and Barter from the Niger, G. Mann from the Bagroo River) are all Xylopia longipetala . Oliver (1868) maintained Bentham’s concept, and it is not surprising that Vallot (1882) found it necessary to argue that there were two distinct species, and that Bentham had confused them. Vallot proposed Xylopia dunaliana Vallot as a replacement name for X. acutiflora (under which he placed Unona oxypetala in synonymy), and he retained the name X. parviflora for the second species, but X. dunaliana Vallot is a superfluous name and illegitimate.

The type material of Unona acutiflora in G-DC comprises 4 sheets of a collection made by Smeathman, each sheet with slightly different labeling but all seeming to contribute to the description and illustration in Dunal (1817) and so here regarded as the holotype. There are three sheets of a Smeathman collection at BM that are considered to be isotypes. As with the combination Xylopia aethiopica made by Richard, we follow the conclusion of Brizicky (1962) in accepting the year of publication of the combination Xylopia acutiflora as 1841, rather than the printed date of 1845. Dunal published Candolle’s manuscript name Unona oxypetala in the same publication as Unona acutiflora ( Dunal 1817), which was based on a specimen collected by Afzelius and seen by Candolle in the Lambert Herbarium. The two names therefore have equal priority, but the name X. acutiflora has historically been used for the species. According to Miller (1970), the specimens of Afzelius in the Lambert Herbarium were purchased by William Pamplin, working on commission for Wilhelm Friedrich Klotzsch, who acquired the specimens for the Berlin herbarium. An Afzelius specimen, identifiable as this species, survives at B, but the specimen has both flowers and fruits, and only flowers are mentioned in the protologue. The fruits and seeds are not attached to the twigs, and it is possible that they became associated with the specimen later. We initially labeled the B sheet as an isotype, pending a better understanding of the distribution of the Lambert Herbarium collections, but it is now clear that this specimen, and specifically the branches with flowers attached, is more appropriately designated as a lectotype.

Figures

Figure 33. Xylopia unguiculata, X. acutiflora, and X. piratae. A-D, L-O X. unguiculata A Monocarp, lateral view B Seed C Leaves D Flower, lateral view L, M Staminodes, abaxial view N Stamen, abaxial view O Carpel, lateral view with ovary wall cut away to show arrangement of ovules E-G X. acutiflora E Monocarp, lateral view, attached to pedicel F Leaves G Flower, lateral view H-K X. piratae H Flower bud, lateral view I Leaves J Flower, lateral view K Fruit. A-B from Le Testu 1179 (BM) C-D from Reitsma & Reitsma 1923 (NY) E-G from Beentje 879 (WAG) H-J from de Koning 4999 (WAG) K from de Wilde 356 (P) L-O from McPherson 16960 A (MO).

Figure 34. Distributions of Xylopia acutiflora, X. dinklagei, X. monticola, X. piratae, X. thomsonii, and X. unguiculata. Bolder lines represent country borders, fainter lines lakes and major rivers.