Xylopia odoratissima Welwitsch ex Oliver, Fl. trop. Afr. 1: 31. 1868.

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 104-108

20. Xylopia odoratissima Welwitsch ex Oliver, Fl. trop. Afr. 1: 31. 1868. Fig. 3G

Xylopicrum odoratissimum (Welwitsch ex Oliver) Kuntze, Revis. gen. pl. 1: 8. 1891. Type. ANGOLA. Huíla Province, [Morro de Lopollo, 1859-60, ex Hiern (1896, p. 10)], F. Welwitsch distrib. no. 757 (lectotype: BM! [000511059, flowering specimen on lower half of sheet], photos GH! NY!).

Xylopia antunesii Engler & Diels, Notizbl. Königl. Bot. Gart. Berlin 2: 299. 1899.

Xylopicrum antunesii (Engler & Diels) Kuntze, Deutsch. Bot. Monatsschr. 21: 173-174. 1903. Type. ANGOLA. Benguella, Huíla, J. M. Antunes 64 (holotype: B! [100153150]).

Description.

Shrub or tree up to 9 m tall, d.b.h. up to 15 cm, with wide-spreading crown; bark light gray to brown, smooth or flaking. Twigs brown to dark brown, densely pubescent, the hairs 0.2-0.6 mm long, eventually light gray, reddish brown or brownish gray, glabrate; nodes occasionally with two axillary branches. Leaf with larger blades 4.7-6.9 cm long, 2.2-3.3 cm wide, subcoriaceous to chartaceous, concolorous, oblong, lanceolate-oblong, or elliptic, occasionally ovate, oblanceolate, or obovate, apex obtuse or rounded, occasionally broadly acute, base broadly cuneate to rounded, sparsely pubescent (usually denser on the midrib) adaxially, pubescent abaxially; midrib raised to plane adaxially, raised abaxially, secondary veins weakly brochidodromous to camptodromous, 6-11 per side, diverging at 45-70° from the midrib, slightly raised on both surfaces, higher-order veins raised on both surfaces; petiole 3.5-8 mm long, shallowly canaliculate, densely pubescent. Inflorescences axillary, 1-3-flowered, the pedicels arising separately from axil, only rarely 2 from a short common peduncle, pubescent; pedicels 3.5-7 mm long, 1.3-1.5 mm thick, pubescent; bracts 1-2, attached near the midpoint, caducous, 1.1-2 mm long, semicircular, apex obtuse to rounded, pubescent abaxially; buds linear, often falciform, apex acute, base bulbous. Sepals somewhat spreading at anthesis, 1/4-2/5-connate, 2.0-3.0 mm long, 2.3-4.5 mm wide, coriaceous, broadly triangular to semicircular, apex acute to obtuse, pubescent abaxially. Petals creamy yellow, greenish yellow, or dull yellow in vivo; outer petals spreading to recurved at anthesis, 17.2-33.5 mm long, 3.4-3.9 mm wide at base, 1.0-1.7 mm wide at midpoint, coriaceous, linear, often somewhat falcate, apex acute to obtuse, keeled on abaxial surface, gray-puberulent adaxially, yellow-brown sericeous abaxially; inner petals spreading to recurved at anthesis, 12.8-24.6 mm long, 2.1-3.0 mm wide at base, 0.6-1.0 mm wide at midpoint, coriaceous, linear, apex acute, base with undifferentiated margin, longitudinally ridged on both surfaces, densely puberulent on both surfaces except for glabrous base. Stamens 160-200; fertile stamens 1.1-1.6 mm long, narrowly oblong to clavate, apex of connective 0.1-0.3 mm long, shieldlike, overhanging anther thecae, glabrous or minutely papillate, anthers 9-12-locellate, filament 0.3-0.5 mm long; outer staminodes 1.6-1.8 mm long, quadrate or broadly clavate, apex obtuse to truncate; inner staminodes 0.9 mm long, broadly clavate, apex truncate; staminal cone 1.7-2.4 mm in diameter, 1.0-1.4 mm high, completely concealing the ovaries, rim even. Carpels 7-10; ovaries ca. 0.8 mm long, stigmas more or less connivent, 2.5-2.6 mm long, linear, apices acute, with a tuft of yellow to rusty hairs. Torus slightly concave beneath the ovaries, otherwise flat, 1.9-2.8 mm in diameter. Fruit of up to 7 glabrate monocarps borne on a pedicel 7-8 mm long, 1.9-2.5 mm thick, sparsely pubescent; torus of fruit ca. 3 mm in diameter, ca. 2.5 mm high, ovoid to globose. Monocarps with green to red exterior in vivo, endocarp color unknown, 1.8-2.6 cm long, 1.0-1.3 cm wide, ca. 0.8 cm thick, oblong, sometimes weakly torulose, apex obtuse with a short beak 1-2 mm long, base subsessile or contracted into a stipe 2.5-7 mm long, 2.5 mm thick, strongly rugose, occasionally pruinose; pericarp 0.2-0.4 mm thick. Seeds up to 4 per monocarp, in a single row, lying oblique to perpendicular to long axis, 10.3-12.2 mm long, 6.7-7.7 mm wide, 5.1-6.1 mm thick, ellipsoid, semicircular in cross-section, narrowed and truncate at micropylar end, rounded at chalazal end, brown, smooth, dull, raphe/antiraphe not evident, micropylar scar 1.5 mm long, 1.0-1.5 mm wide; sarcotesta red in vivo; aril absent.

Phenology.

Specimens with flowers have been collected from January to May and those with fruits from December to February.

Distribution

(Fig. 26 ). Southern Angola and northeastern Namibia, east to western Zambia and south to northern Botswana and west-central Zimbabwe; most fre quently reported from woodlands on Kalahari sands dominated by Baikiaea plurijuga (mukusi, Rhodesian teak), occasionally in miombo woodland dominated by Brachystegia spiciformis , or occasionally from the edges of riverbanks; 900-2000 m.

Local names.

Mtjibi wenduna (Sindebele, Goldsmith 51/56), omuriandele (Antunes & Dekindt 3142), setundewanga (Sik, Pardy 4805), situndu bawanga (Lozi, White 2062), situnduboanga (Barotze, Jenkins 1), situndubwanga ( “Bantu,” McFerren 30), umtshibi omduna (Ndebele, Mashasha 169). On the label of White 2062, it is explained that the name situndu bawanga is translated as "That which cannot be left," attesting to the medicinal properties attributed to the plant by local people.

Additional specimens examined.

ANGOLA. Huíla, clairieres de la montagne de Lopolo, 1800 m, Dec 1900 (fr), Antunes & Dekindt 3142 (P-3 sheets); Huíla, Polygonal Florestal da Humpata, ca. 5 km NE of Humpata, ca. 8 km SW of Lubongo, 14°58'54.9"S, 13°26'01.6"E, 2018 m, 26 Jan 2009 (fl), Bester 9279 (MO); Humber A bords du Cunene, Tyipelongo-Mucope-Danguena, 1910-1920 (fl, fr), Bonnefousc & Villain 92°2 (P); at Kubango near the forte Princeza Amelia, s. d. (fl), Gossweiler 3940 (BM, K); Bié, Kubango, 1905 (fr), Gossweiler 4043 (BM); Huíla, Mannyino, 1760 m, Jan 1901 (fl), Herbar. Huíla 276 (A); Huíla [or Bié], Ganguelas, Vila Artur de Paiva, margens do Cubango, 1450 m, 12 Jan 1960 (fl), Mendes 2086 (MO); Huíla, Huíla, próx. da M. Catolica do Mennhino , 6 Feb 1955 (fl), Santos 92 (MO, WAG); Huíla, Quilengues, Lucondo, ca. 1500 m, 28 Oct 1959 (st), Teixeira & Andrade 358 (PRE); Huíla, prope Lopolo, Jan 1860 (fr), Welwitsch 92 (BM) . NAMIBIA. Eastern Caprivi, Katima Mulilo District, Katima Mulilo , 17 Feb 1971 (fl), Breitenbach 1312 (PRE); Kavango Andara at camp of Dept. Agriculture, Grid Ref. 1821 AB, 10 Feb 1958 (fl), Hilbert 158 (K); Eastern Caprivi, Katima Mulilo District , Katima Mulilo, 11 Feb 1968 (fl), McFerren 30 (PRE); Andara, R. C. Miss. Station , on Island near camp on bank of river, 24 Apr 1977 (fl), Müller & Giess 533 (PRE); Okavango Territory, Andara Camp, Okavango River banks, 18 Mar 1966 (fl), Tinley 1414 (PRE, WAG); O Caprivi, Katima Mulilo, 30 Jan 1975 (fl), Vahrmeijer & du Preez 2508 (PRE) . ZAMBIA. Southern: Livingstone District, Livingstone , 12 Feb 1956 (fl), Gilges 586 (K, PRE); Livingstone , 12 Feb 1930 (fl), Jenkins 1 (BM); Livingstone , 22 Feb 1963 (fl), Lawton 1041 (K).- Western : Mongu District , Makapaela Pan , 25 km N of Mongu, 15°02'S, 23°14'E, 1020 m, 15 Feb 1999 (fl, Bingham & Luwiika 11893 (K); Mongu District , Kataba local forest, 20 km [ “mm”] SE of Mongu, 15°27'S, 23°16'E, 1030 m, 16 Feb 1999 (fr), Bingham & Luwiika 11905 (K); Shisheke District 103 km SE of Senanga on road to Sesheke, 1050 m, 1 Feb 1975 (fl), Brummitt et al. 14224 (EA, MO, RSA, WAG); Kalabo District ["Barotse Province"], near Kalabo Boma, 13 Feb 1952 (fl), White 2062 (BM, K); Kalabo District , 5.6 km W of Kama Health Center, 5.5 km E of Lukona Secondary School in Kalamaba L. F. No. 379, 15°22'36.9"S, 22°53'44.5"E, 930 m, 21 Mar 1996 (fl), Zimba et al. 829 (MO, PRE).- Province unknown: Baikiaea forest region, Kalahari sand, S. N. Western Rhodesia , 1937 (st), Martin 786 (BM) . BOTSWANA. Kazungula , Apr 1936 (fl), Miller B 132 (BM) . ZIMBABWE. Wankie District, Fuller Forest Reserve, Mar 1960 (fl), Armitage 102/60 (MO); Victoria Falls , 10-15 Mar 1932 (fl), Brain 8875 (K, MO); Shangani / Bubi District , Gwampa Forest Reserve , 3000 ft, Feb 1956 (fl), Goldsmith 51/56 (K, PRE); Wankie District , Victoria Falls National Park , 14 Feb 1980 (fl), Kandanda 11 ([= s. n. at B?], MO); Wankie District , Victoria Falls village , 24 Jan 1979 (fl), Mshasha 169 (K, MO, WAG); Nyamanahlovu Dist. , Jan 1929 (fr ped), Pardy 4502 (MO); Nyamanahlovu Dist. , Jan 1931 (fl), Pardy 4805 (B, BM, K); Bulawayo, May 1898 (st), Rand 422 (BM) .

Xylopia odoratissima is a shrub or spreading treelet with uniformly small leaves and with an inflorescence consisting of 1-3 flowers. The petals are long and often falcate at the apices, even in bud. The outer petals are widened abruptly at the base, such that the flower buds appear bulbous. The monocarps are reported to be red at maturity, and are prominently rugose when dried. Purple coloration at the bases of the inner petals is apparently absent (Fig. 3G ). Xylopia odoratissima is a species restricted to the Baikiaea and Brachystegia woodlands on Kalahari sands from Angola to western Zimbabwe, where it occurs with Pseudolachnostylis and Parinari mobola as associates. It seems not to occur north or east of the Zambezi River, where it is replaced by Xylopia shirensis , which, while similar, can grow to be a tree up to 14 m tall and has larger leaves that are more variable in shape. The petals of X. shirensis are shorter and seldom falcate, and the inner petals have purple coloration at the base. The outer petals narrow gradually, and the widening of the base of the buds is therefore gradual as well. The monocarps are reported to be green at maturity, and are smooth or at most weakly wrinkled when dried.

Collectors frequently remark on the fragrance of the flowers. Welwitsch (as translated by Hiern 1896) wrote "flowers very fragrant, exceeded in the pleasantness of the aroma only by the species of Schrebera but their fragrance is far more intense." The label of Jenkins 1, from southern Zambia, states "scent much resembling a sweet pea. Only noticeable after sunset. Then the tree → v. fragrant."

Typification of names based on Welwitsch collections is problematic because Welwitsch held his specimens privately, and they were not distributed to herbaria until after his death. As explained by Albuquerque et al. (2009), the bulk of the collection was returned to LISU during the period 1876 to 1879. The second-best set remained at BM, and duplicates were distributed from LISU to other herbaria later on.

In this particular case, Welwitsch must have shown his collections to Daniel Oliver for use in preparing the first volume of the Flora of Tropical Africa, published in 1868, that is, while they were still in Welwitsch’s private collection and had not been divided up into sets. Oliver’s protologue gives a detailed description of the plant, in particular of the flowers. The fruits are described briefly and the seeds not at all. One of the specimens with flowers therefore seems to be the most appropriate choice as a lectotype.

According to Hiern (1896), Xylopia odoratissima was found by Welwitsch in flower in December of 1859 and in January and February of 1860. Welwitsch numbered his collections as he curated them, grouping together all collections thought to represent the same species under the same collection number ( Albuquerque et al. 2009). All of the collections seem to have come from the same locality, so the only piece of information that can separate them is the date. Unfortunately, most of the duplicates seen lack a specific date.

A branch with flowers in the lower half of sheet 000511059 at BM is chosen as the lectotype. It is accompanied by a handwritten label that specifies Lopollo Dec. 1859. Photographs of this specimen have been distributed to a number of herbaria. In the absence of information about the date of collection, however, other specimens with flowers are not considered isolectotypes, although with better information, they may be identifiable as such in the future. For example, some of the specimens with flowers have leaves that have dried a darker color than those of the BM specimen. A specimen at LISU, which we viewed through JSTOR Global Plants, has been annotated as the “holotype,” but it cannot be so, given that the original description was based upon multiple gatherings. In addition, the date given on the specimen is April 1860, which does not accord with the flowering times for the species given in Hiern (1896), and we cannot see the specimen well enough to tell if it has flowers or fruits on it. For the record, we have seen Welwitsch 757 specimens from B (single sheet, flowering specimen, printed ticket without date, only information written on the label is 757 Xylopia odoratissima Welw.), BM (non-lectotype material on sheet 000511059), C (two sheets, seen via JSTOR), G (single sheet, specimen with flowers but leaves are darker than on BM sheet), K, LD, LISU (2 sheets), M, P (2 sheets, one ex herb. Pierre), and PRE.

The syntype Smith s. n., from the Congo River, is Xylopia longipetala and does not seem to have contributed significantly, if at all, to the protologue of Xylopia odoratissima and is therefore excluded as a possible lectotype .

Figures

Figure 3. Flowers of representative Xylopia species. A Flower from type collection of Xylopia globosa from Gabon B Xylopia tenuipetala from Mozambique C Xylopia quintasii from Gabon D Xylopia aethiopica from Gabon E Xylopia longipetala from Mali, representing a record for the country not otherwise documented F Xylopia piratae from Ivory Coast G Xylopia odoratissima from Zambia H Xylopia arenaria from Tanzania I Xylopia collina from Tanzania. A, D by Thomas L. P. Couvreur B by Frances Chase C by Ehoarn Bidault E by Philip Birnbaum F by Celine Pirat G by Warren McClelland H and I by D. M. Johnson.

Figure 26. Distributions of Xylopia shirensis, X. odoratissima, X. holtzii, X. gracilipes, X. nilotica, and X. torrei. Bolder lines represent country borders, fainter lines lakes and major rivers.