Xylopia shirensis (Engler & Diels) 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 : 108-110

21. Xylopia shirensis (Engler & Diels) D. M. Johnson & N. A. Murray comb. nov. Fig. 27M-P

Xylopia antunesii var. shirensis Engler & Diels, Monogr. afrik. Pflanzen-Fam. 6: 66. 1901. Type. MALAWI. Southern Region, Shiri Highlands ["Shire Hochland"], Chnambola, comm. 1881, J. Buchanan 237 (holotype: K!).

Description.

Shrub or a tree up to 14 m tall, d.b.h. up to 20 cm; bark cracking. Twigs brown to dark brown, initially tomentose, the hairs 0.3-1.2 mm long, becoming light brown to gray or dark gray-brown, glabrate or with pubescence somewhat persistent; nodes occasionally with two axillary branches. Leaf with larger blades 4.5-10.2 cm long, 2.1-5.1 cm wide, chartaceous to subcoriaceous, concolorous or slightly discolorous, elliptic, oblong, or ovate, rarely oblanceolate, apex broadly acute, obtuse, or rounded, rarely nearly truncate or emarginate, base broadly cuneate to rounded, occasionally truncate or subcordate, sparsely pubescent on both surfaces; midrib slightly raised to plane adaxially, raised abaxially, secondary veins irregularly brochidodromous, 7-15 per side, diverging at 45-70° from the midrib, these and higher-order veins slightly raised on both surfaces; petiole 3.5-11 mm long, shallowly canaliculate or somewhat flattened, pubescent. Inflorescences axillary or from axils of fallen leaves, 1-6-flowered, pedicels emerging side by side from axil or rarely from a common peduncle, pubescent; peduncle ca. 3.5 mm long, with 2 pedicels per peduncle; pedicels 2.8-7 mm long, 1.2-1.5 mm thick; bracts 2, at or proximal to midpoint, caducous or somewhat persistent, lower 1.9-2.6 mm long, upper 1-1.7 mm long, semicircular to ovate, apex obtuse or rounded; buds lanceolate, apex more or less acute. Sepals slightly spreading at anthesis, 1/4-1/2-connate, 1.5-3.0 mm long, 2.3-3.4 mm wide, chartaceous to coriaceous, triangular, broadly ovate, or semicircular, apex acute, pubescent abaxially. Petals yellow-green to pale yellow, the inner petals crimson or purple-tinged on the inner base in vivo; outer petals spreading at anthesis, 12.2-20.9 mm long, 2.3-3.3 mm wide at base, 1.0-1.6 mm wide at midpoint, coriaceous, linear-lanceolate, apex obtuse, densely pubescent on both surfaces, the pubescence more yellowish abaxially; inner petals spreading to weakly geniculate at anthesis, 9.3-14.6 (-21.5) mm long, (1.6-) 2.0-2.9 mm wide at base, 0.5-1.0 mm wide at midpoint, coriaceous, linear-subulate, apex obtuse, base with undifferentiated margin, densely gray-puberulent on both surfaces, except for glabrous base. Stamens ca. 120; fertile stamens 1.0-1.2 mm long, narrowly oblong, apex of connective 0.1-0.2 mm long, shieldlike, overhanging anther thecae, glabrous, anthers 8-11-locellate, filament 0.3-0.5 mm long; outer staminodes 1.2-1.4 mm long, clavate to oblong, apex obtuse, rounded, or truncate; inner staminodes ca. 0.8 mm long, rectangular, apex truncate; staminal cone 1.2-2.3 mm in diameter, 0.8-1.1 mm high, concealing only the bases of the ovaries, rim laciniate. Carpels ca. 7; ovaries ca. 1 mm long, narrowly oblong, pubescent, stigmas loosely connivent, 2-2.6 mm long, linear, glabrous except for a tuft of hairs at the apex. Torus concave beneath ovaries but otherwise flat, 2.0-3.7 mm in diameter. Fruit of up to 8 glabrate monocarps borne on a pedicel 5.5-10 mm long, 1.9-2.5 mm thick, pubescent to glabrate; torus 3.3-5 mm in diameter, 2-3.0 mm high, staminal cone often persistent on it, depressed-globose. Monocarps with pale green to purple-red exterior and green endocarp in vivo, 1.2-3.8 cm long, 1.0-1.2 cm wide, 0.8-1.1 cm thick, oblong, irregularly torulose, apex rounded or obliquely truncate, occasionally with a short beak ca. 1 mm long, base contracted into a stipe 3.5-9 mm long, 2-3 mm thick, slightly obliquely wrinkled, finely verrucose, occasionally pruinose; pericarp 0.2-0.3 mm thick. Seeds 1-6 per monocarp, in a single row or two irregular rows, oblique to long axis, 8.5-11 mm long, 6.0-8.3 mm wide, 5.1-6.5 mm thick, ellipsoid, broadly elliptic in cross-section, brown, slightly wrinkled, dull, micropylar end truncate, chalazal end rounded, raphe/antiraphe not evident, micropylar scar ca. 2.5 mm long, elliptic; sarcotesta deep orange in vivo; aril absent.

Phenology.

Specimens with flowers have been collected from October to February, and with fruits in October and from December to February.

Distribution

(Fig. 26 ). Occurs from southern Democratic Republic of the Congo east to western Tanzania and south to eastern Zambia and Malawi in open woodland, often dominated by Brachystegia spp. and often on sand, at elevations of 470-1770 m.

Local names.

Akiziga (Kilungu, Bredo 6276), chikiza or kikiza (Chimambwe (Musa) and Chilungu), Michelmore 1045), kizika (Kikungu, Bredo 6232), mshenene (Kinyamezi, Wigg F.H. 1121), msyenene (Kinyamwezi, Shabani for Bullock 10), mtuzya (Kinyamwezi, Mwiga et al. 174).

Additional specimens examined.

DEMOCRATIC REPUBLIC OF THE CONGO. Haut-Katanga: Kisanga [near Lubumbashi], 1200 m, 20 Jan 1984 (fl), Malaisse 13134 (MO, WAG); prés de Mulwe forêt Katanguaise, 7 Jan 1949 (fl), de Witte 5144 (K, P) . TANZANIA. Iringa: Iringa District, 44 km on Mafinga-Madabira road, 08°14'S, 34°58'E, 1300 m, 26 Mar 2006 (fl), Bidgood et al. 5122 (K, MO) .- Kigoma: Bangwe , Kigoma District, Western Province , T. T., 2450 ft, Nov 1956 (buds), Procter 558 (NHT) .- Mbeya: T7, Mbeya District, above Chimala Mission , 8°50'S, 34°01'E, 1200 m, 23 Mar 1988 (fl), Bidgood et al. 642 (K, NHT, WAG); Madibira, 1200 m, 28 Jan 2001 (fr), Congdon 588 (K) .- Shinyanga: Kahama , 18 mi along Ushirombo R., 1 Jan 1936 (fl), Burtt 5459 (BM, K) .- Tabora: Tabora, 28 May 1970, Collinson U. 9 (EA) ; Tabora, s. d., Hammerstein 5838 (EA, K); S of Kuliwa-Tabora Region, 5°30'S, 32°40'E, 15 Nov 1979 (fl), Lawton 2178 (K, P); S Tabora, Lindeman 440 (K); Sikonge South Tabora, 29 Sep 1940 (yg fr), Lindeman 788 (K); Ulyakulu Forest Reserve , Tabora, Manolo 183 (K) ; Tabora, Tabora Rural District, Mtakuja Village, Urumwa Forest Reserve , 4°53'29"S, 32°45'25"E, 1040 m, 6 Jul 1999 (fl, yr fr), Mwiga et al. 174 (MO); collected from the Tabora Beekeeping Institute Plantation , 28 Nov 1976 (buds), Shabani 1131 (K, WAG); without definite locality [probably Tabora], Wigg 523 (MO, US) ; Simbo Reserve, Tabora , June 1938 (st), Wigg F.H. 1121 (K) . ZAMBIA. Eastern: Ndundu Hill , 1770 m, 5 Oct 1966 (fl), Richards 31484 (K); Chadiza, 850 m, 29 Nov 1958 (fr), Robson 770 (BM, K) .- Luapula: Western Province, Fort Rosebery District, near Lake Bangweulu, Samfya Mission , 24 Aug 1952 (fr), Angus 304 (BM, K, MO) ; Western Province, Fort Rosebery District, near Lake Bangweulu, Samfya Mission , 28 Aug 1952 (old fls), White 3156 (K).-Northern: Abercorn , 10 Nov 1948 (st), Bredo 6232 (BR) ; Abercorn District, Ulungu County, Mchinda village, 13 Nov 1948 (fr), Bredo 6276 (BR); Kawimbe , 11 Nov 1949 (fl), Bullock 1414A (K, P); Mutinondo Wilderness , Mpika , 1500 m, 24 Dec 2005 (fr), Congdon 709 (K) ; Abercorn District, 4500', Feb 1932 (fl), Gamwell 106 (BM); NE of Abercorn, 11 Dec 1934 (fl), Michelmore 1045 (EA, K); Abercorn , 1933, Miller 133D (A, BM, K) ; Abercorn District, Chilongowelo, in open ground close to Plain of Death , 4800 ft, 29 Sep 1954 (fl), Richards 1881 (K) ; Abercorn District, close to Lucheche stream by road to Abercorn Club turning, 5000 ft., 23 Feb 1954 (fl), Richards 2326 (K) ; Abercorn District, Kawimbe , 1680 m, 2 Jan 1956 (fl, fr), Richards 6833 (K) ; Abercorn District, Kawimbe, 1740 m, 20 Sep 1960 (buds, fr), Richards 13266 (K); Uninji Pond, Mbala , 5000 ft, 3 Nov 1968 (fl), Sanane 346 (B, K) ; Northern Province, Abercorn District, near top of Sunzu Hill , 18 Nov 1952 (fl), White 3711 (K, MO) . MALAWI. Machinga District, Chikala Mt. Liwonde Forest Reserve, Grid Ref. 36LYU6927, 1460 m, 30 Feb 1982 (fl), Patel 977 (K) ; Machinga District, Chikala Mt. Liwonde Forest Reserve, Grid Ref. 36LYU6927, 1460 m, 5 Dec 1982 (fl), Patel & Tawakali 1028 (K); N Region , Karonga District, Vinthukutu Forest Reserve , 10 Jan 1990 (fl), Patel & Usi 4605 (PRE); N. Prov ., Nkhata Bay District, Nkhata Bay, Chikale Beach , 1550 ft., 5 Dec 1976 (fl), Pawek 11992 (MO, WAG; N. Prov ., Chitipa District, Kaseye Mission , 10 mi E of Chitipa, 1270 m, 26 Dec 1977 (fl, fr), Pawek 13379 (K, MO, WAG); N. Prov ., Mzimba District, 5 mi. NE of Mzambazi , 22 Jan 1978 (fr), Pawek 13659 (K, MO, WAG); N. Prov ., Mzimba District, 5 mi. NE of Mzambazi , 22 Jan 1978 (fl), Pawek 13660 (MO) ; Nkata District, Chinteche nr. Sand Dunes, L. Nyasa , 570 m, 21 Feb 1961 (fl), Richards 14438 (K) ; Central Province, Senga Bay Hotel, nr. Salima, 470 m, 16 Feb 1959 (fl), Robson & Steele 1628 (BM, K, PRE) .

Xylopia shirensis includes specimens formerly identified as Xylopia odoratissima in Boutique (1951b), Robson (1960), and Verdcourt (1971b), but it differs consistently from that species in the somewhat longer and wider leaves, up to 10.2 cm long and 5.1 cm wide versus 6.9 cm long and 3.3 cm wide, more variable size and shape of the leaves, the smaller flowers that are grouped into inflorescences of 1-6 flowers, flower buds less bulbous at the base, and petals marked with red or purple on the inner base. The two species are not known to overlap in distribution, although both occur frequently in Brachystegia woodland.

The label of Congdon 588 from western Tanzania notes that the plant is a food plant for the larvae of the Abantis butterfly; Cock and Congdon (2011) report that this is one of a number of food plants from a variety of families that are used by Abantis paradisea (Butler). The Congdon specimen also includes a photograph of the dehisced monocarp, showing the green endocarp and orange sarcotesta that characterize the members of the X. odoratissima subgroup. Several specimens show an oblong gall-like structure developing within the androecium of the flower.

Figures

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.

Figure 27. Xylopia longipetala, X. holtzii, X. katangensis, and X. shirensis. A-F X. longipetala A Fruit B Seed, side view C Seed, view of micropylar end D Base of inner petal, adaxial view E Habit F Gynoecium surrounded by staminal cone with a few attached stamens G-K X. holtzii G Habit H, I Detached monocarps J Gynoecium surrounded by staminal cone with a few attached stamens K Base of inner petal, inner (adaxial) surface L X. katangensis, habit M-P X. shirensis M Fruit N Habit O Seed, view of micropylar end P Seed, side view. A-C from Jongkind & Nieuwenhuis 3031 (WAG) D, F from McPherson 17911 (MO) E from Halle & Le Thomas 190 (P), and following photograph of fresh flowers of same collection in Le Thomas (1969) G, J, K from Johnson et al. 1938 (OWU) H, I from Templer H 167 / 53 (K), L from Letouzey 4498 (MO) M from Richards 13266 (K) N from Richards 14438 (K) O, P from Bredo 6276 (BR).