Research Article |
Corresponding author: Guang-Wan Hu ( guangwanhu@wbgcas.cn ) Academic editor: Norbert Holstein
© 2020 Neng Wei, Zhi-Xiang Zhong, David Kimutai Melly, Solomon Kipkoech, Benjamin Muema Watuma, Veronicah Mutele Ngumbau, Peris Kamau, Guang-Wan Hu, Qing-Feng Wang.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wei N, Zhong Z-X, Melly DK, Kipkoech S, Watuma BM, Ngumbau VM, Kamau P, Hu G-W, Wang Q-F (2020) Zehneria grandibracteata (Cucurbitaceae), an overlooked new species from western Kenyan forests. PhytoKeys 165: 85-98. https://doi.org/10.3897/phytokeys.165.57399
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Zehneria grandibracteata, a new species of Cucurbitaceae from western Kenya, is described here, based on morphological and molecular data. It has long been misidentified as the widely-distributed species Z. scabra. However, it differs by its ovate leafy probract at the base of the inflorescences, subglabrous condition of the entire plant, shorter receptacle-tube and filaments, as well as denser and sessile inflorescences. Furthermore, the molecular phylogenetic analysis of Zehneria, based on nrITS sequences, further supports the argument that Z. grandibracteata should be segregated from Z. scabra.
East Africa, Flora of Kenya, phylogeny, taxonomy, Zehneria scabra
Zehneria
During field investigations of the Kenyan flora in 2016, a Zehneria species with evident leafy probracts attracted the authors’ attention for the first time. Herbarium specimens had been identified as Z. scabra Sond. in
Specimens of East African Zehneria deposited in the herbaria of K, EA and HIB were studied, as well as relevant digitised specimens from online databases, including specimens from the herbaria B, BR, BM, E and P (herbarium acronyms follow
Aiming to delimitate the phylogenetic position of our Zehneria collections, a total of 63 sequences were used to infer a phylogenetic tree. Amongst these sequences, 60 accessions representing 38 Zehneria species were included and another three accessions from Cucumis, Coccinia, Benincasa were treated as outgroups, according to
Species and specimen-voucher | Accession No. |
---|---|
Benincasa hispida, Renner et al. 2760 (M) | KJ467162 |
Coccinia grandis, DeWilde & Duyfjes 22270 (L) | HQ608207 |
Cucumis melo, Mitchell & Schaefer 68 (TUM) | KY434575 |
Neoachmandra boholensis, Ramos 2-107/37215 (US) | KY523290 |
Neoachmandra capillacea, Achigan-Dako 07nia757 | AM981144 |
Neoachmandra capillacea, Wieringa 11246 (M) | KY523291 |
Neoachmandra cunninghamii, Telford 12489 (M) | KY523292 |
Neoachmandra filipes, Brass 31994 (US) | KY523293 |
Neoachmandra gilletii, De Wilde 11246 (L) | KY523280 |
Neoachmandra hallii, Achigan-Dako 91sn003 | AM981143 |
Neoachmandra hermaphrodita, Phonsena 440938 (K) | KY523281 |
Neoachmandra japonica, Su EM0045T001 | MK771856 |
Neoachmandra japonica, Zhang 1518 (M) | KY523294 |
Neoachmandra leucocarpa, Junghuhn s.n. (U) | KY523295 |
Neoachmandra odorata, He s.n. (K) | KY523307 |
Neoachmandra odorata, Wallich 6706 (M) | KY523297 |
Neoachmandra pentaphylla, Guillaumin 8611 (US) | KY523286 |
Neoachmandra pentaphylla, McKee 3504 (US) | KY523300 |
Neoachmandra samoensis, Sykes 170278 (L) | KY523301 |
Neoachmandra samoensis, Whistler W2908 (B) | MG680626 |
Neoachmandra thwaitesii, Pallithanam 3637 (BLAT) | KY523314 |
Neoachmandra wallichii, Fujikawa 053262 (TUM) | KY523310 |
Zehneria anomala, Gilbert 1681 (EA) | MT733849 |
Zehneria anomala, Gillett 16503 (M) | KY523289 |
Zehneria baueriana, McKee 38396 (GH) | KY523288 |
Zehneria baueriana, Sykes 533 (US) | KY523284 |
Zehneria bodinieri, Dwivedi 1004 (DUH) | KY523266 |
Zehneria bodinieri, Tanaka 080913 (MBK) | KY523267 |
Zehneria emirnensis, Mitchell & Schaefer 25 (TUM) | KY523268 |
Zehneria grandibracteata, SAJIT 6670 (EA/HIB) | MT733851 |
Zehneria grandibracteata, SAJIT 6966 (EA/HIB) | MT733852 |
Zehneria grandibracteata, SAJIT 6968 (EA/HIB) | MT733850 |
Zehneria guamensis, Perlman 14 (US) | KY523273 |
Zehneria longiflora, SAJIT 6669 (EA/HIB) | MT733853 |
Zehneria longiflora, SAJIT 6672 (EA/HIB) | MT733854 |
Zehneria marlothii, Merxmueller & Giess 30031 (M) | KY523283 |
Zehneria maysorensis, CALI 10625 | KY523386 |
Zehneria maysorensis, Dwivedi 1002 (DUH) | KY523256 |
Zehneria microsperma, Loveridge 64 (GH) | KY523274 |
Zehneria minutiflora, SAJIT 8861 (EA/HIB) | MT733855 |
Zehneria minutiflora, Stolz 1139 (M) | KY523296 |
Zehneria monocarpa, SAJIT 7172 (EA/HIB) | MT733856 |
Zehneria monocarpa, SAJIT 7173 (EA/HIB) | MT733857 |
Zehneria oligosperma, Luke 11710 (EA) | MT733858 |
Zehneria pallidinervia, Holstein 52 (M) | KY523287 |
Zehneria pallidinervia, SAJIT 6241 (EA/HIB) | MT733859 |
Zehneria perpusilla, Santapau 13074 (BLAT) | KY523255 |
Zehneria perrieri, Mitchell & Schaefer 10 (TUM) | KY523270 |
Zehneria pisifera, Hoogland & Pullen 5926 (GH) | KY523275 |
Zehneria polycarpa, Mitchell & Schaefer 36 (TUM) | KY523276 |
Zehneria racemosa, Mendes 1841 (M) | KY523298 |
Zehneria scabra, Schaefer 05/317 | HQ202009 |
Zehneria scabra, SAJIT 6501 (EA/HIB) | MT733860 |
Zehneria scabra, SAJIT 6554 (EA/HIB) | MT733861 |
Zehneria scabra, SAJIT 6736 (EA/HIB) | MT733863 |
Zehneria scabra, SAJIT 6873 (EA/HIB) | MT733865 |
Zehneria scabra, Schaefer s.n. | KY523278 |
Zehneria scrobiculata, Bolus 11558 (M) | KY523285 |
Zehneria scrobiculata, Schimper 164 (M) | KY523299 |
Zehneria tahitensis, Sachet 2662 (US) | KY523313 |
Zehneria tridactyla, Espirito 3053 (M) | KY523321 |
Zehneria tuberifera, SAJIT-6350 (EA/HIB) | MT733866 |
Zehneria tuberifera, SAJIT-W0044 (EA/HIB) | MT733867 |
The Table
Dissimilar characters to distinguish Zehneria grandibracteata, Z. longiflora and Z. scabra, based on
Character | Z. grandibracteata | Z. scabra | Z. longiflora |
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Stem | Thick, up to 2.5 cm in diam., subglabrous | Thick, up to 1.5 cm in diam., puberulous | Thin, up to 0.8 cm in diam., subglabrous |
Leaf blade | Membraneous, deeply cordate to subtruncate at the base, subglabrous, with sparsely scabrid setulose on both sides | Membraneous to subcoriaceous, deeply cordate to subtruncate at the base, puberulous on both sides or sparsely scabrid-setulose on the veins beneath | Slightly fleshy, membraneous, subglabrous, cordate to subtruncate at the base, with sparsely scattered bristles on adaxial surface only |
Male inflorescence | Sessile, subumbelliform | Subumbelliform or shortly racemiform sessile or pedunculate axillary clusters | Sessile or pedunculated, subumbelliform or racemiform |
Probract | Well-developed, leafy, ovate, up to 18 × 12 mm, incurved, beak-like, persistent | Linear, hooked or curly, minute, caduceus | Linear, hooked or curly, less than 10 mm long, minute, caduceus |
Perianth | Receptacle-tube 1.8–3 mm long, hairy only on inner surface, petal lobes ca. 1.8 mm long | Receptacle-tube 2.0–5.5 mm long, hairy on both inner and outside surface, petal lobes 1.5–3.5 mm long | Receptacle-tube 6.0–7.5 mm long, hairy only on inner surface, petal lobes 2.0–3.0 mm long reflexed |
Pedicle | 3–12 mm long in male, 4–6 mm long in female | 1.5–10 mm long in male, 0.4–11.0 (20.0) mm long in female | 4–20 mm long in male, 8–25 mm long in female |
Filament length | ca. 1.5 mm | 1–2.5 mm | ca. 3.5 mm |
Style length | 2–3.5 mm long, stigma ca. 1.5 mm in diam. | 2–4 mm long, stigma ca. 2 mm in diam. | 6–7 mm long, stigma ca. 2 mm in diam. |
Ovary | Glabrous, subglobose, with neck up to 1 mm long | Puberulous, subglobose to fusiform to beaked, with neck up to 2 mm long | Glabrous, subglobose, with neck up to 3.5 mm long |
Fruit | 2–16 in clusters, sparsely covered with tiny protuberances, subglobose, 8–10 mm in diam. | 1–10 in clusters, usually glabrous, globose, 8–13 mm in diameter, or ellipsoid, 10–12 × 7–8 mm | 2–8 in clusters, densely covered with tiny protuberances, globose, 9–11 mm in diam. |
In total, 60 sequences representing 38 Zehneria species were included in our dataset. Multiple sequences per species were identical as to some species, like Z. grandibracteata, Z. anomala, Z. tuberifera and Z. longiflora. They might, however, be different regarding the other species, such as Z. scabra, Z. pallidinervia and Z. minutiflora. The final trimmed alignment of 63 sequences has 721 columns, with 92 parsimony-informative sites. Z. grandibracteata differs in the 71th position (G vs. A) and 208th position (A vs. T) of ITS1 alignment from other Zehneria species. HKY+F+G4 was selected as the best-fit model to infer the Maximum Likelihood tree and Bayesian tree. As shown in Figure
Bayesian tree inferred from the nrITS sequences dataset to elucidate the phylogenetic position of Zehneria grandibracteata. Bayesian posterior probability values > 0.9 and bootstrap values ≥ 70% are shown below the branches. The new species is highlighted in bold and red colour and Z. scabra is noted in blue colour.
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
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!)
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.
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.
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 (
Flowering and fruiting from April to July and November to January, corresponding to the wet seasons of the bimodal rainfall pattern of this region.
The epithet “grandibracteata” refers to the fairly large leafy probract of this new species.
(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!).
Our Z. grandibracteata collections are recognised as monophyletic, separated from the related Z. scabra. The possible reasons to explain the paraphyly of Z. scabra in our phylogeny are 1) the nrITS provides limited phylogenetically-informative sites in Zehneria and mutations on few loci produced inconsistent phylogenetic topology; 2) the two accessions collected by Schaefer here probably should be Z. monocarpa, which was separated from Z. scabra recently (
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.
The broadly circumscribed concept of Zehneria may represent a better natural group, while there is no comprehensive classification system for this group until now.
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).
We would like to thank the following herbaria BM, BR, EA, HIB, K and P for hosting our visits or providing relevant high-resolution images during our study. Gratitude is also given to the subject editor Norbert Holstein and the reviewer Hanno Schaefer for providing useful comments and suggestions on earlier drafts of the manuscript and to Mrs. Lunlun Gao from Huazhong Agricultural University for preparing the distribution map. Lastly, we are also grateful to the Kenya Forest Service (KFS) for issuing fieldwork permits (permit number: RESEA/1/KFS 98 and RESEA/1/KFS 22) to conduct the field investigations. This work was supported by grants from the National Natural Science Foundation of China (grant number 31970211) and from Sino-Africa Joint Research Center, CAS (SAJC201614).
Modified CTAB protocol on the base of
Data type: molecular data