Xylopia holtzii Engler, Bot. Jahrb. Syst. 34: 159. 1904.

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 99-100

17. Xylopia holtzii Engler, Bot. Jahrb. Syst. 34: 159. 1904. Figs 27G-K , 28A

Type.

TANZANIA. Dar-es-Salaam Region, Dar-es-Salam, Puguberge, Dichter Busch , 29 Feb 1903, W. Holtz s. n. (lectotype, here designated: B! [100153143]) .

Tree up to 20 m tall, d.b.h. up to 30 cm, clear bole to 8 m on 12 m tree, trunk fluted or with small narrow buttresses at base; bark light gray to gray-brown, sometimes blotched with white, smooth or transversely ringed by fine lenticels. Twigs light brown, orange-brown, gray-brown, brownish gray, or blackish brown, initially pubescent, the hairs 0.1-0.8 mm long, becoming glabrate; nodes occasionally with two axillary branches. Leaf with larger blades 4.8-11.4 cm long, 1.7-4.4 cm wide, chartaceous to subcoriaceous, concolorous to slightly discolorous, lanceolate to narrowly oblong, elliptic, or oblanceolate, apex obtuse, often attenuate, rarely emarginate, base broadly cuneate to rounded, glabrous to sparsely pubescent adaxially, sparsely appressed-pubescent abaxially; midrib slightly raised to plane adaxially, raised abaxially, secondary veins weakly brochidodromous, 8-17 per side, diverging at 40-70° from the midrib, slightly raised on both surfaces, higher-order veins indistinct adaxially, indistinct to slightly raised abaxially; petiole 3-12 mm long, shallowly canaliculate to flattened, pubescent or rarely glabrous. Inflorescences axillary, 1-6-flowered, pubescent; at least some inflorescences with peduncles, 1-2 peduncles per axil, 2-4.5 mm long; pedicels 2-4 per peduncle, or arising directly from axil, 2.0- 7.5 mm long, 0.7-0.8 mm thick; bracts 2-3, evenly spaced along length of pedicel, caducous or rarely persistent, 0.9-1.3 mm long, ovate to semicircular, apex acute to rounded; buds linear, slightly falciform, apex acute. Sepals erect to slightly spreading at anthesis, 2/5-1/2-connate, 1.6-2.4 mm long, 1.9-2.8 mm wide, coriaceous, orbicular, apex acute to short-acuminate, appressed-pubescent abaxially. Petals yellow-green, yellow, or cream-colored with pinkish purple at the base adaxially in vivo; outer petals curved outward but with the apices weakly incurved at anthesis, 10.5-25 mm long, 2.1-3.7 mm wide at base, (0.7-) 0.9-1.9 mm wide at midpoint, coriaceous, linear, apex acute to obtuse, weakly keeled on abaxial surface, gray-puberulent adaxially, golden appressed-pubescent abaxially; inner petals curved outward but with the apices strongly incurved at anthesis, 7.7-21.4 mm long, 1.6-2.7 mm wide at base, 0.5-1.2 mm wide at midpoint, coriaceous, linear-subulate, apex acute, base with undifferentiated margin, ridged on both surfaces, densely puberulent on both surfaces. Stamens 60-70; fertile stamens 1.0- 1.5 mm long, narrowly oblong, apex of connective red to reddish purple in vivo, 0.1-0.3 mm long, shieldlike, overhanging anther thecae, glabrous, anthers 10-13-locellate, filament 0.3-0.5 mm long; outer staminodes 0.9-1.4 mm long, quadrate to broadly clavate, apex truncate; inner staminodes 1.0- 1.2 mm long, clavate, apex truncate; staminal cone 0.7-1.9 mm in diameter, 0.7-1.1 mm high, concealing only the bases of the ovaries, rim laciniate. Carpels 5-12; ovaries 0.9-1.1 mm long, narrowly oblong, pubescent; stigmas loosely connivent, 0.9-1.8 mm long, linear, apices pubescent. Torus flat, 1.6-2.4 mm in diameter. Fruit of up to 8 pubescent monocarps borne on a pedicel 4.5-8 mm long, 1.6-3.0 mm thick, pubescent; torus 3.0- 6.7 mm in diameter, 2.6-5.4 mm high, irregularly globose. Monocarps with green exterior and white (immature?) endocarp in vivo, up to 8 per fruit, 2.3-4.0 cm long, 0.8-1.3 cm wide, 0.7-0.8 cm thick, oblong, irregularly torulose, apex obtuse to rounded, often with a wide beak 1.5-2.2 mm long, base contracted into a stipe 6-10 mm long, 3-3.5 mm thick, finely verrucose, pubescence most persistent on stipe; pericarp 0.4-1.0 mm thick. Seeds 1-3 per monocarp, in a single row, lying oblique to long axis, 11.8-12.3 mm long, 5.9-7.0 mm wide, 4.9-6.0 mm thick, flattened-ellipsoid, broadly elliptic in cross-section, obliquely truncate at micropylar end, rounded at chalazal end, brown, smooth, shiny, raphe/antiraphe not evident, micropylar scar 1.4-1.9 mm long, 0.9-1.0 mm wide, oblong, elliptic, or ovate-elliptic; sarcotesta orange in vivo; aril absent.

Phenology.

Specimens with flowers have been collected in February, March, from May to July, and from October to December, and with fruits from January to March, in May and August, and from October to December.

Distribution

(Fig. 26 ). Occurs near the Indian Ocean coast from southern Kenya to central Tanzania, extending inland in Tanzania to the scarp of the Udzungwa Mountains and the Selous region, growing in dry evergreen or semi-deciduous forest, less commonly in miombo ( Brachystegia ) woodland, at elevations of 0-800 (-1670) m.

Local names.

Lulema mbala (Rodgers 388); mlawilila (Kidoe, Abeid 550), muporota (Kihehe, Haerdi 214/0), mporoto (Kimbunga, Haerdi 214/0), mporota (Kisagara, Haerdi 214/0). An ethnobotanical study of the Digo people on the coast between Tanga and Mombasa reported mnyinyi [shining leaves], mchiza tasaka, and mwahula tsaka [forest breaker, i.e. emergent through the canopy] ( Pakia 2005) as additional local names in that area.

Additional specimens examined.

KENYA. Kwale: Jardini , Jun 1962 (fl), Birch 62/188 (K); Jilori, Black M. 37 (K) ; Kwale District, Mwasangombe Forest 15 km SW of Kwale, 230 m, 27 Aug 1953 (fr), Drummond & Hemsley 4015 (B, EA, FI-T, K); Jardini Hotel, forest ca. 30 km S of Mombasa, 22-23 Jun 1970 (fl), Faden 70/201 (EA, K, MO); Diani Forest , 1 km N to 1.5 km S of the turnoff for the new road to Jadini Hotel , 4°19'S, 11-13 Jul 1972 (fl), Gillett & Kibuwa 19846 (B, BR, EA, K, MO, NHT, P, WAG); Gillett & Kibuwa 19847 (K); Mkongani North FR, 4°17'S, 39°19'E, 280 m, 13 Jul 1987 (bud), Luke & Robertson 508 (MO); Diani Forest , 4°20'S, 39°34'E, 5 m, 16 Jun 1994 (fl), Robertson 6957 (K, MO); Mrima Hill, 4°29'S, 39°16'E, 170 m, 4 Feb 1989 (st), Robertson et al. MDE 50 (K); Gogoni, 30 mi S of Mombasa, 7 Oct 1953 (fl, fr), Templer H 167/53 (K-2 sheets, MO) .- Lamu: Witu District, Mambasasa , 7 Nov 1957 (old fl), Greenway 9471 (FI-T, K, PRE) . TANZANIA. Iringa : Kilolo District, Kisegese Village , at base of hill, 08°01'58"S, 036°22'46"E, 360 m, 13 Mar 2006 (fl, fr), Festo et al. 2213 (MO) .- Lindi: Selous Game Reserve , T8, ca. 15 km SSW of Kingupira, 8°35'S, 38°31'E, ca. 150 m, 15 Nov 1975 (fl), Vollesen 2992 (K, WAG) .- Morogoro: Hundupila / Kiberege, Ifakara , 6 Mar 1959 (fl), Haerdi 214/0 (K, WAG); along trail to Mwanihana Peak, SW of Udzungwa Mountains National Park headquarters, 19/ 20 Feb 1996 (fl, fr), Johnson & Murray 1889 (OWU spirit collection) ; Ulanga District, Iragua village, 100 m SE of main road from Iragua to Itete , 8°33'54"S, 36°29'52"E, 360 m, 21 Jan 1999 (fr), Kayombo 1589 (MO); Sanje Logging Camp, 1670 m, 30 Dec 1980 (fr), Rodgers 388 (DSM) .- Pwani: Bagamoyo District, Zaraninge Forest Reserve , near WWF office, near forest guards’ camp, 6°17'S, 38°34'E, 150 m, 8 Jun 1999 (fl), Abeid 550 (MO); Pugu-Berge, s. d., Holtz 3202 (B, PH) ; Coast Region, Kisarawe District, Pugu Forest Reserve , bus roundabout area ca. 4 km E of Kisarawe, 06°53'30"S, 39°06'00"E, 200 m, 26 May 1996 (fl), Johnson & Murray 1938 (OWU) ; Rufiji District, forest near WWF Office, 08°18'57"S, 38°57'39"E, 250 m, 6 Dec 1998 (fl), Kibure 320 (MO); T6, Kisarawe, Pugu Forest Reserve , June 1954 (fl), Semsei 1718 (EA, K-2 sheets); Selous Game Reserve , Beho Beho, 07°40'S, 37°55'E, 250 m, 6 Jun 1977 (fl), Vollesen 4619 (DSM, WAG) .- Tanga: Kihuhwi R., E Usambaras, 900 ft, Greenway 4959 (K).- Region undetermined: T6, Nahomba , Selous Game Reserve , 7 Nov 1970 (fr), Ludanga 1166 (K); Kijawe, Selous Game Preserve, 2 Feb 1971 (fl), Ludanga 1193 (EA, K); T6, Selous Game Reserve , 24 May 1978 (fr), Mhoro 2917 (MO); T8, Balani water hole, Selous Game Reserve , 4 Oct 1970 (fl), Rodgers 1148 (K) .

Xylopia holtzii is another member of the X. odoratissima subgroup of eastern and southern Africa, set apart from other species of the subgroup by the combination of branched inflorescences, purple coloration at the bases of the petals, and pubescent stipitate monocarps that are only weakly verrucose. The number of branched inflorescences on herbarium specimens varies-some sheets of Vollesen 2992 from the Selous region, for example, have no branched inflorescences, but correspond to the species in leaf and floral morphology. In Tanzania, X. holtzii is not known to overlap in distribution with either X. shirensis or X. gracilipes . The former is a species of the interior miombo woodlands to the west of the Eastern Arc Mountains, while the latter is only known from the miombo woodlands of the extreme southern Tanzania, where it reaches the northern limit of its distribution.

Given the variable nature of the habitats in which this species occurs, it is not surprising that tree associates vary correspondingly from location to location. The most frequently mentioned associates are Milicia excelsa and species of Erythrophleum and Diospyros . Marshall (2007) reported X. holtzii (as X. parviflora ) to be one of the ten most common canopy tree species in disturbed semi-deciduous forest plots in the Udzungwa Mountains, comprising 7.5% of the 3346 canopy tree individuals sampled.

The type specimen of Xylopia holtzii cited above, which was marked as the Typus at B, bears information slightly different from that which is included in Engler’s protologue: “Sansibarküstgebiet: Pugu-Berge in Buschgehölzen auf rotem Lehm (Holtz n. 897 - Fruchtend im Feb 1903)." The specimen is not discordant with the protologue, but in the case that there was a specimen with this number that has now been lost, the extant specimen is designated as a lectotype rather than assumed to be the holotype.

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).

Figure 28. Xylopia keniensis and X. tanganyikensis, with leaves of X. holtzii and X. longipetala for comparison. A Leaf of X. holtzii from Tanzania B Leaf of X. longipetala from Ghana C-E X. keniensis C Habit D Fruit E Inflorescence F-O X. tanganyikensis F Pedicel, sepals, and staminal cone G Base of inner petal, adaxial view H Base of outer petal, adaxial view I Flower, lateral view J Carpel K, L Habit M Stamen, abaxial view N Staminode, abaxial view O Fruit. A from Semsei 1718 (K) B from Jongkind & Nieuwenhuis 2130 (WAG) C, D from Luke & Robertson 2723 (MO) F-J, L-N from Nishida 57 (K) K, O from Abeid et al. 1028 (L). Reproduced with the permission of the Board of Trustees, Royal Botanic Gardens Kew.