Xylopia keniensis D.M.Johnson

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/137022402/137048337

Conservation

LC - least concern

Johnson DM et al. 2017. New species of Xylopia (Annonaceae) from East Africa. Kew Bulletin 72:11. DOI 10.1007/S12225-017-9681-X

Type

Type: Kenya, Kwale Distr.: Shimba Hills, 4.2407°S, 39.4218°E, 390 m, 30 Dec. 2009 (fl), Luke & Luke 13949 (holotype EA!; isotypes BR, K!, MO — 2 sheets!, NHT, PRE, US).

Morphology General Habit

Tree 15 – 25 m tall with a straight cylindrical trunk and rounded crown

Morphology Twigs

Twigs greenish brown to blackish, glabrous or initially short-pubescent but soon glabrate, becoming light grey with age; nodes occasionally with two axillary branches

Morphology Leaves Leaf lamina

Lamina of larger leaves 6.7 – 10.5 cm long, 2.6 – 3.7 cm wide, chartaceous, shiny adaxially, dull and paler abaxially, lanceolate to elliptic, occasionally oblong or elliptic-oblanceolate, apex sharply acuminate, the acumen 6 – 18 mm long, occasionally obtuse, base cuneate to rounded, glabrous or with a few hairs at the base of the midrib adaxially, sparsely appressed-pubescent to glabrate abaxially; midrib slightly raised to plane adaxially, raised abaxially; secondary veins 12 – 15 per side, diverging at 60 – 75° from the midrib, weakly brochidodromous; secondary and higher order veins slightly raised on both surfaces; petiole 2 – 5.5 mm long, shallowly canaliculate, drying black, pubescent to glabrous

Morphology Reproductive morphology Inflorescences

Inflorescences axillary, usually from the axils of fallen leaves, 1- or rarely 2-flowered, sparsely pubescent; pedicels 2.8 – 3.9 mm long, bracts 2, attached in the distal ½ of the pedicel, persistent or not, 1.2 – 1.6 mm long, broadly ovate to crescent-shaped, apex acute, pubescent; buds lanceolate, apex acute

Morphology Reproductive morphology Flowers Calyx

Sepals ⅓-connate, 2.2 – 2.7 mm long, 2.3 – 2.4 mm wide, subcoriaceous, broadly ovate to triangular, apex obtuse to acute, sparsely pubescent abaxially

Morphology Reproductive morphology Flowers Corolla

Outer petals cream-coloured with reddish pink bases at anthesis in vivo, erect at anthesis, 13.7 – 19.3 mm long, 2.2 – 2.6 mm wide at base, 0.9 – 1.0 mm wide at midpoint, linear, flat on both surfaces, apex obtuse, densely puberulent except for the glabrous warty base adaxially, golden-sericeous abaxially; inner petals cream-coloured with reddish-pink bases at anthesis in vivo, geniculate at anthesis, 11.0 – 16.3 mm long, 1.8 – 2.2 mm wide at base, 0.5 mm wide at midpoint, linear-subulate, longitudinally ridged on both surfaces, thickened at widest point and sharply differentiated from concave base adaxially, apex acute, densely puberulent on both surfaces except for the glabrous base

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens c. 85 (including staminodes), 1.0 – 1.3 mm long, narrowly oblong; apex of anther connective reddish pink at anthesis in vivo, 0.2 – 0.25 mm long, forming a flat cap over the tops of the anther thecae, smooth or finely papillate; filament 0.3 – 0.5 mm long, forming ¼ –⅓ of stamen length; outer staminodes c. 10, 1.2 – 1.5 mm long, oblong, inner staminodes 3 – 4, smaller than fertile stamens and outer staminodes; staminal cone 0.7 mm high, 1.3 mm in diam., irregularly laciniate around the rim

Morphology Reproductive morphology Flowers Gynoecium Carpels

Carpels c. 6; ovaries c. 0.3 mm long, oblong, pubescent; stigmas 1.8 – 2 mm long, filiform, apex acute

Morphology Reproductive morphology Flowers

Torus 1.8 mm in diam., flat

Morphology Reproductive morphology Flowers Pedicel

Pedicel of fruit 5 mm long, 2.6 mm thick, glabrate; torus of fruit c. 4 mm in diam., 4.5 mm high, glabrate

Morphology Reproductive morphology Fruits

Monocarps green with a red endocarp in vivo, up to 4 per fruit, 2.8 – 3.5 cm long, 1.0 – 1.6 cm wide, 1.1 – 1.4 cm thick, clavate-pyriform to ovoid, usually with a longitudinal ridge running down one side, apex obtuse, tapered to the base but not stipitate; pericarp 0.4 – 1.0 mm thick, verrucose, glabrate (rarely a few hairs at base)

Morphology Reproductive morphology Seeds

Seeds arranged in two rows, lying perpendicular to long axis of per monocarp, orange-red in vivo, becoming dark brown when dry, 4 – 6 per monocarp, 11.0 – 11.2 mm long, 7.2 – 7.3 mm wide, 5.1 mm thick, oblong to ellipsoid, obovate to elliptic in cross-section, slightly wrinkled/ roughened, rounded at chalazal end, obliquely truncate at micropylar end, raphe/antiraphe not visible on surface; micropylar scar c. 3 mm long, 1.5 mm wide, elliptic, flat; aril absent

Distribution

Africa: Kenya, Kwale District near the coast.

Ecology

Coastal forest from sea level up to 430 m; associates at one site (from Luke & Robertson 2723) included species of Antiaris, Milicia, Lovoa, Celtis, Quassia, Hymenaea, Julbernardia, and Manilkara in the canopy, and Leptonychia, Diospyros, Warneckea [Memecylon] and many Rubiaceae shrubs in the understorey.

Conservation

There are two locations for this species in the Shimba Hills: all the Longomwagandi forest records can be taken as one. If the cell size is again taken as 3.17 km2 then the AOO is 30 km2 and the EOO is 31 km2. There is little or no threat to the Shimba Hills population which is here assessed as Least Concern but Conservation Dependent (LC (CD)), a term under discussion with the Red List Committee at present.

Phenology

Flowers have been collected in May and December, fruits in March and August.

Note

This species has a strong resemblance to Xylopia parviflora sensu Verdcourt and has been identified as that species (Luke 2005). It differs, however, on several points. Its leaves are usually sharply acuminate, shiny above, and glabrous to occasionally sparsely pubescent, while those of X. parviflora are obtuse to acute, dull above, and always sparsely pubescent abaxially and occasionally adaxially as well. Even in seedlings grown side-by-side the more pronounced sheen of the X. keniensis leaves is evident. The petals of both whorls in X. parviflora typically all curve inward at anthesis, while in X. keniensis the outer petals are erect and the inner petals are geniculate, with the apices emerging at right angles to the outer petals in the gaps between them (Fig. 1E, F). The monocarps of X. parviflora sensu Verdcourt are stipitate, often obliquely wrinkled and sparsely to densely pubescent, with the seeds arranged in a single row, while those of X. keniensis are sessile, verrucose, at most slightly wrinkled but sometimes with a raised ridge running longitudinally down one side, and glabrate, with seeds arrange in two distinct rows. Populations of “Xylopia parviflora” from the Usambara region of Tanzania should be re-examined for possible presence of this species. This species is thus far known only from Kenya and at present is the only Xylopia species known to be endemic to the country. Resembling Xylopia parviflora sensu Verdcourt but differing by the sharply acuminate and nearly glabrous leaf laminas (vs obtuse to acute and distinctly pubescent in X. parviflora sensu Verdcourt), the inner petals strongly geniculate at anthesis (vs curved inward) and the sessile monocarps with the seeds arranged in two rows (vs stipitate and with seeds in a single row).