Zehneria grandibracteata G.W. Hu, Neng Wei & Q.F. Wang, 2020

Wei, Neng, Zhong, Zhi-Xiang, Melly, David Kimutai, Kipkoech, Solomon, Watuma, Benjamin Muema, Ngumbau, Veronicah Mutele, Kamau, Peris, Hu, Guang-Wan & Wang, Qing-Feng, 2020, Zehneria grandibracteata (Cucurbitaceae), an overlooked new species from western Kenyan forests, PhytoKeys 165, pp. 85-98 : 85

Zehneria grandibracteata G.W. Hu, Neng Wei & Q.F. Wang sp. nov. Figures 3 , 4

Diagnosis.

It is close to Z. scabra , but differs by its consistently ovate leafy probracts (linear minute or even absent in Z. scabra ), subglabrous condition of the entire plant (puberulous in Z. scabra ), shorter receptacle-tube (1.8-3 mm long vs. 2-5.5 mm in Z. scabra ) and filaments (ca. 1.5 mm long vs. 1-2.5 mm in Z. scabra ), as well as sessile and denser inflorescences (cluster of 8-30 in male, 6-22 in female vs. 2-60 in male, 1-16 in female in Z. scabra ) (Table 2 ).

Type.

Kenya. Nandi County, South Nandi Forest, Morongiot area, 0°04'N, 35°00'E, elev. 1980 m, 20 April 2018, Sino-Africa Joint Investigation Team (SAJIT) 006973 (Female) (holotype HIB!; isotype EA!, HIB!)

Description.

Perennial climber, 8 m or longer; rhizome robust, woody when old, up to 2.5 cm in diam., roots slender, branched; stem many-branched, grooved, usually contorted when aged, sparsely puberulous except densely hairy at nodes. Leaves simple, petioles 2-7 cm long, grooved adaxially, subglabrous; blades 38-65 × 28-46 mm, ovate-cordate in outline, shallowly 3-lobed occasionally, membraneous, subglabrous, deeply cordate to subtruncate at base, margin slightly sinuate-toothed, apex acuminate and apiculate; scabrid-punctate above, 3-11 main veins sunken adaxially and protrudent abaxially, with sparsely-scattered bristles on both sides, especially on veins and margins; tendrils simple, up to 15 cm long. Dioecious. Inflorescence base with a well-developed leafy probract, up to 18 × 12 mm, ovate, incurved, beak-like, persistent, 2-3 main veins from base, base cordate, apex acuminate. Male inflorescences axillary, sessile, subumbelliform, 8- to 30-flowered, pedicels 3-12 mm long; receptacle-tube 1.8-3 mm long, campanulate, greenish-cream, turning into orange when aged, inner surface densely hairy, outside surface glabrous; sepal lobes 5, ca. 1 mm long, dentiform, pale green; petal lobes 5, ca. 1.8 × 1.5 mm, triangular-ovate, white, turning cream to orange when aged. Stamens 3, inserted in middle of tube; filaments ca. 1.5 mm long, subglabrous, lower half fused with tube; anthers ca.1 mm long, ellipsoid, 2-thecae; thecae 1 mm long, vertical, slightly curved, connective elliptic, with finely papillose hairs; disc ca. 1 mm in diam., depressed globose, obscurely trilobed, elevated. Female inflorescences axillary, sessile, 6- to 22-flowered in umbelliform clusters; pedicel 4-6 mm long; perianth similar to male flowers; ovary subglobose, glabrous, with evident neck up to 1 mm long; style 2-3.5 mm long, glabrous, stigma ca. 1.5 mm in diam., with 3 down-curved papillose lobes; staminodes 3, ca. 1.5 mm long, linear, glabrous, at base of the tube; disc ca. 1.8 mm in diam., annular, 3-lobed, surrounding base of style, free from tube. Fruits clustered, 8-10 mm in diam., subglobose, subglabrous, sparsely covered with tiny protuberances, turning from green to orange when mature; pedicel 5-10 mm long. Seed ovate in outline, narrowly bordered, lenticular, compressed.

Distribution and ecology.

Numerous populations of this new species have been documented in the western parts of Kenya’s forests, including Morongiot and Kobujoi areas of South Nandi Forest, Kapsasur area of Nandi Centre, Yale River Trail of Kakamega Forest, Timbilil and Sambret Catchment area of south-western Mau Forest. It usually climbs over tree trunks or twines around shrubs in moist forests or at forest margin at elevations of 1950-2230 m.

Conservation status.

This new species was found in the western Kenyan forests with numerous localities. It is locally quite common in the wild and frequently grows in forests or at forest margins. Thus, we assess it to be "Least Concern" (LC) based on IUCN Red List Categories and Criteria ( IUCN 2001).

Phenology.

Flowering and fruiting from April to July and November to January, corresponding to the wet seasons of the bimodal rainfall pattern of this region.

Etymology.

The epithet " grandibracteata " refers to the fairly large leafy probract of this new species.

Additional specimens examined

(Paratypes). Kenya. Nandi County, South Nandi Forest, Kobujoi area, 34°57'E, 0°04'N, elev. 1970 m, 11 December 2016, SAJIT 006670 (EA! HIB!); Nandi County, South Nandi Forest, Morongiot area, 0°04'N, 34°55'E, elev. 1980 m, 19 April 2018, SAJIT 006966 (EA! HIB!) and SAJIT 006968 (EA! HIB!); Nandi County, Nandi Centre, Kapsasur area, elev. 1970 m, 18 April 2018, SAJIT s.n. (HIB!); Kakamega County, Kakamega Forest, Yale River Trail, 0°16'N, 34°52'E, 7 January 2017, SAJIT s.n. (HIB!); Kericho County, Changana Tea Estate, 5.3 miles south of Kericho Town, 0°27'S, 35°18'E, 22 November 1967, Perdue R.E. and Kibuwa S.P. 9179 (BR! EA! K!); Kericho County, Sambret Catchment of southwestern Mau Forest, 0°22'S, 35°23'E, 2160 m, 5 July 1962, Kerfoot O. 3375 (EA! K!); Kericho County, Sambret Catchment of Southwestern Mau Forest, 0°26'S, 35°22'E, 2230 m, 16 Jan 1963, Kerfoot O. 4696 (EA!); Kericho County, Timbilil of southwestern Mau Forest, 0°18'S, 35°31'E, 2130 m, Jan 1963, Kerfoot O. 4708 (EA!).

Figures

Figure 3. Photographs showing vegetative characters of Zehneria grandibracteata A climbing stem of female plant in habitat B adaxial lamina C creeping stem D abaxial lamina E probracts at different developing stages F tendril and probract at base of female inflorescence. Scale in picture E represents cm.

Figure 4. Photographs showing reproductive characters of Zehneria grandibracteata A male inflorescence B male flower, side view C male flower, top view D dissected male flower showing disc and stamens E female inflorescence F female flower, side view G female flower, top view H dissected female flower showing staminodes I pistil and disc J infructescence K cross-section of fruit. Scale bars: 2 mm (B-D, F-I); 1 cm (J, K).