Zehneria monocarpa G.W.Hu, V.M.Ngumbau & Q.F.Wang, 2020

Ngumbau, Veronicah Mutele, Nyange, Mwadime, Wei, Neng, Malombe, Itambo, Hu, Guang-Wan & Wang, Qing-Feng, 2020, Zehneria monocarpa (Cucurbitaceae), a new species from the relicts of Kenya’s coastal forests, Phytotaxa 443 (3), pp. 258-264 : 259-261

Zehneria monocarpa G.W.Hu, V.M.Ngumbau & Q.F.Wang sp. nov. ( Fig.1 & 2 )

Diagnosis:— The new species differs from Zehneria oligosperma Jeffrey (1962: 367) and Z. longiflora G.W.Hu & Q.F.Wang in Wei et al. (2017: 89) by 1–23 conspicuous dark green glands on the apex of the leaf (vs blade glands absent in Z. oligosperma , and only 1–12 blade glands in Z. longiflora ); leaf base shallowly to deeply notched [vs leaf base cordate or (sub)truncate in Z. oligosperma , and cordate to truncate in Z. longiflora ]; female flower solitary, rarely 2 in each leaf axil (vs female flowers rarely solitary, ca. 2–18-flowered in umbelliform clusters in Z. oligosperma , and Z. longiflora ); inner part of receptacle tube entirely hairy (vs inner part of receptacle tube hairy at mouth in Z. oligosperma , and on upper half in Z. longiflora ); fruit solitary (vs fruits clustered in both Z. oligosperma and Z. longiflora ); seeds ovate, ca. 3–5 × 2 × 0.6 mm (vs seeds broadly ovate, 5 × 4 × 1 mm in Z. oligosperma , and ovate, narrowly bordered in Z. longiflora ).

Type:— KENYA. Kilifi County, Chasimba area , elev. 200 m, 12 September 2018, Sino-Africa Joint Investigation Team ( SAJIT) 007172 (Female) (holotype HIB!; isotype EA!, HIB!)

Herbaceous climber or trailer, ca. 3–6 m long. Stems arising from perennial branched rootstock, usually rounded on older ones and grooved on young ones, glabrous or sparsely scabrid. Tendrils simple, 35–125 mm long. Leaf blade membranous, triangular-ovate to oblong-ovate, 10–62 × 5–70 mm, palmately lobed on non-flowering stems of young individuals, middle lobe sometimes 3-lobed; base shallowly to deeply notched; apex obtuse and mucronate; margins faintly sinuate to entire; 5-veined at base; with 1–23 conspicuous dark green glands, glands confined to apical part; scabrid to scabrid-punctate adaxially, glabrous abaxially except with sparsely scattered bristles on main veins. Petiole 5–45 mm long, glabrous or scabrid. Dioecious. Inflorescence with ca. 20 mm long cochleate probract. Male inflorescence with 4–17 flowers in pedunculate umbelliform clusters; peduncle 5–30 mm long; pedicel 1–6(–10) mm long, usually with a coaxillary pedicellate solitary flower or rarely 2; receptacle-tube campanulate, 2–3(–4) × 2–3(–4) mm, entirely hairy within; calyx lobes 5, 0.2–0.4 mm long; corolla lobes 5, white, triangular-ovate, 1–2 × 1.0– 1.5 mm, recurved, hairy within; stamens 3, inserted at the bottom of receptacle-tube and beside the disk; filaments ca. 3 mm long, hairy; anthers basifixed, elliptic, ca. 1 mm long, thecae 2, elliptic, fringed with pilose hairs; disk elevated, depressed-globose, 3-lobed, free from tube, ca. 1.5 mm in diam. Female flowers solitary, rarely 2 in each leaf axil; pedicel 4–10 mm long; ovary globose to sub-globose, with deep green vertical stripes, punctate, 2–6 × 2–5 mm; receptacle-tube campanulate, 1–4 × 2–3 mm, entirely hairy within; calyx lobes 5, 0.8–1.0 mm long; corolla lobes 5, white to creamish yellow, triangular-ovate to lanceolate-ovate, recurved at apex, 1.5–2.0 × 1.0– 1.5 mm, hairy within; staminodes 3, densely hairy, 3 mm long inserted at the bottom of the receptacle-tube beside disk; style 2–4 mm long; stigma 2–3 mm wide, 3-lobed; disk annular, 3-lobed, surrounding base of style, free from tube, ca. 1 mm high. Fruits solitary, fruit stalk 5–12 mm long, globose to sub-globose, pitted, red when ripe, 10–12 × 6–10 mm. Seed ovate, compressed, ca. 3–5 × 2 × 0.6 mm.

Distribution and ecology:— Five populations of the new species have been found in the coastal forests of Kenya, at Chasimba area and Kaya Muhaka. It has not been collected or recorded elsewhere. At Chasimba and Kaya Muhaka it was found trailing on rocks and climbing on tree trunks.

Phenology:— Zehneria monocarpa was found in flower and fruit from August to December.

Etymology:— Epithet ‘ monocarpa ’ refers to its solitary fruit in each leaf axil.

Additional specimens examined (paratypes):— KENYA. Kilifi County, Chasimba area , elev. 200m, 12 September 2018, SAJIT 007173 a (Male) ( EA!, HIB!), SAJIT 007173 b (Female) ( EA!, HIB!) ; 2 December 2016, V. M. Ngumbau & M. Nyange SAJIT-V-0399 (Female) ( EA!, HIB!) ; Kwale County, Kaya Muhaka , elev. 30 m, 28 August 2018, M. Nyange 2404a (Male) & 2404b (Female) ( EA!, HIB!) .

Figures

FIGURE 1. Photographs of Zehneria monocarpa. A. Habit. B. Branch with fruits. C. Abaxial leaf side of mature plant (showing glands). D. Adaxial leaf side of mature plant. E. Palmately lobed leaf of juvenile stem (abaxial). F. Palmately lobed leaf of juvenile stem (adaxial). G. Young branch. H. Root. I. A node with (i) Probract. Scale bar: the ruler used in the photos is calibrated in centimeter (cm; thick lines). Photographs:A, C, D, I. by G.W. Hu; B, E–G. by V.M. Ngumbau.

FIGURE 2. Photographs of Zehneria monocarpa. A. Branch with female flowers. B. Branch with male inflorescence. C. Open female flower showing stigma, style and hair inside corolla. D. Male flower.E. Female flower with corolla removed. F.Open male flower showing stamens, disk and hairy corolla. G. Cross-sectional dissection of fruit. H. Ripe fruits. I. Seed. Scale bar: the ruler used in the photos is calibrated in centimeter (cm; thick lines). Photographs by G.W. Hu.