Peponium elgonense Neng Wei, G.W.Hu & Q.F.Wang, 2020

Mutie, Fredrick Munyao, Rono, Peninah Cheptoo, Kathambi, Vivian, Wei, Neng, Kamau, Peris, Gituru, Robert Wahiti, Hu, Guang-Wan & Wang, Qing-Feng, 2020, Peponium elgonense (Cucurbitaceae), a new species from Mount Elgon in Kenya, Phytotaxa 443 (2), pp. 189-197 : 192-194

Peponium elgonense Neng Wei, G.W.Hu & Q.F.Wang , sp. nov. ( Fig. 2 ).

Diagnosis: — Peponium elgonense is morphologically close to P. cienkowskii ( Fig. 3 ) and P.vogelii ( Fig. 4 ), but differs by being monoecious (vs dioecious) and by its longer ovary (27–30 mm long vs 21–23 mm in P. cienkowskii and 15–26 mm in P. vogelii ).

Type: — KENYA. Bungoma County: Mount Elgon National Park, Endebess Bluff , elev. 2550 m, 24 June 2018, Rono et al. SAJIT-PR 0153 (holotype HIB; isotype EA, HIB) .

Herbaceous vine, 1–3 m long, roots woody, mostly tap rooted with side branches; stems ridged, white villous, densely so on young parts, internodes 37–70 mm long. Leaves simple, palmately 5–7-lobed, 55–70 × 85–115 mm; petioles densely white villous, 15–25 mm long; blade adaxial surface sparsely villous, abaxially subglabrous, densely white villous on nerves; base cordate; margin lacerate, toothed, apex acuminate; tendrils 120–150 mm long, unequally bifid, spiralling just after branching. Probracts 5–10 mm long, spathulate, caudatious. Plant monoecious, male inflorescence and female flower coaxillary, peduncle of male inflorescence longer than pedicel of female flower, holding male flowers above solitary female flower. Male inflorescence racemose, racemes 98–145 mm long, peduncles villous, 60–92 mm long, bracts 7–12 × ca. 1 mm, villous, falcate-spathulate; flowers in clusters of 3–7, maturing in succession, pedicels of mature flowers 8–15 mm long; receptacle tube 13–16 mm long, conical, yellow-green, obscurely green veined, densely white villous at bud, sparsely so at maturity, suddenly constricted at base, calyx lobes 5, linearlanceolate, villous, 4–7 mm long; corolla 11–22 × 6–14 mm, veined, entire, yellow, obovate, inner surface shortly pubescent; stamens 3, inserted into receptacle tube; filaments free, ca. 2 mm long; anthers 6–9 × 3.5–4.0 mm, fused into oblong head. Female flowers solitary, pedicels 8–10 mm long; receptacle tube 4–5 mm long, lobes as in males; ovary ovate-fusiform, 27–30 × 9–10 mm, densely white villous; style 10–11 mm long, stigma irregularly globose with 3 short lobes, ca. 5 mm in diameter. Fruit stalk densely villous, 10–15 mm long; fruit villous, solitary, 70–105 × 35–36 mm, ovate-ellipsoid, narrowing abruptly towards apex into beak of 15–24 mm long, unripe fruit green, grey dotted. Seeds numerous, obovoid, compressed, 7.5–10.0 × 4–5 × 1.0– 1.5 mm, funicle 2.0– 4.5 mm long.

Distribution and ecology: —This species is only known from the Mount Elgon National Park in Kenya. It was collected on an exposed moist rocky wall of a steep cliff, over ca. 100 m above the ground. During the field survey, two adjacent populations extending along the cliff were found at Endebess Bluff.

Conservation status: —According to IUCN (2012) Red List Categories and Criteria, we propose Peponium elgonense to be considered as Data Deficient (DD), since there is limited data in relation to its distribution.

Phenology: —Flowering and fruiting were observed in the field in June.

Etymology: —The species epithet “ elgonense ” is in reference to Mount Elgon where the new species was collected.

Additional specimens examined (Paratypes): — KENYA. Bungoma County: Mount Elgon National Park, Endebess Bluff, elev. 2565 m, 22 June 2018, Rono et al. SAJIT-PR 0121 (EA, HIB).

Specimens examined for Peponium cienkowskii : — KENYA: Kibwezi, 29 Sept. 2018, Hu et al. SAJIT-007204 (HIB).

Specimens examined for Peponium vogelii : — KENYA. Mathews Range , elev. 5800 ft, 8 Jul. 1977, Ichikawa 662 ( EA) ; Marsabit, Mt. Kulal , elev. 1900 m, Jul. 1983, Learamo 1181 ( EA) ; Marsabit District, NE of Ndotos Mountains , Feb. 1979, Synnott 1927 ( EA) ; Mathews Range , elev. 6000 ft, 28 Dec. 1976, Ichikawa 332 ( EA) ; Northern Frontier Province, Narangani, Mt. Kulal , 9 Jun. 1960, Oteke 104 ( EA) ; Mathews Range , elev. 5700 ft, 12 Jul. 1960, Kerfoot 2575 ( EA) ; Mt. Kulal , elev. 6500 ft, 27 Jul. 1958, Verdcourt 2259 ( EA) ; Mt. Nyiru , pt. 494, elev. 1900 m, 5 Feb. 2010, Luke et al. 13978 ( EA) ; Sekerr Mt. , elev. 7800 ft, 1 Aug. 1968, Agnew et al. 10837 ( EA) ; Ngong Escarpment , Oct. 1937, Van Someren 159 ( EA) ; Ngong , Jun. 1937, Van Someren 4 ( EA) ; S end of Aberdare Range, on road between S Kinangop and Kiarutara , 28 km from S Kinangop , elev. 2200 m, 24 Oct. 1976, Kuchar & Msafiri 5453 ( EA) ; Kipkarren , elev. 5500 ft, Oct. 1931, Brodhurst-Hill 537 ( EA) ; Fischers Needle, Njorowa Gorge ( Hell’s Gate ), Naivasha , 7 Jul. 1963, Verdcourt 3681 ( EA) ; Naivasha District, Ol-Longonot Estate , elev. 6400 ft, 28 Jan. 1962, Kerfoot 3598 ( EA) ; Naivasha District, Ol-Longonot Estate , elev. 6400 ft, 14 Jan, 1962, Kerfoot 3588 ( EA) ; Ndeiya Rocks, near Kedong Valley, Rift Valley , 21 Mar. 1965, Agnew 7155 ( EA) ; Nakuru District, Kekopey Ranch , elev. 1950 m, 7 Nov. 1976, Demment 97 ( EA) ; Hills to W of Lake Naivasha, elev. ca. 7000 ft, 15 May 1964, Glover & Tomalin 4529 ( EA) ; Mt. Suswa , elev. ca. 6200 ft, 4 Apr. 1963, Glover 3598 ( EA) ; Kekopey, Gilgil , elev. 2000 m, 13 Jun. 1977, Demment 528 ( EA) ; Laikipia, Mpala , elev. 1660 m, 9 Nov. 1992, Young 3185 ( EA) ; Baringo, Mukutani River , 3 Jul. 1990, Rachel 851 ( EA) ; S of Aberdare Range, on road between S Kinangop and Kiarutara, 19 km from S. Kinangop , elev. 2400 m, 5 Sept. 1976, Kuchar 5233 ( EA) ; Laikipia District, Naibor, Makandura, 6 km from Naibor towards Doldol , 26 km from Nanyuki , elev. 1805 m, 9 Aug. 2007, Kirika et al. 03/18/07 ( EA) ; Embu District, Mwea National Reserve , elev. 1219 m, 6 Mar. 1998, Mwangangi et al. 4843 ( EA) ; Central Province, near Limuru , Kiambu District, elev. 2000 m, 4 Sept. 1987, Fukuoka K-110 ( EA) ; Karura Forest , elev. 5500 ft, 1 Jun. 1941, K.F. Excursion 76 ( EA) ; Nairobi, Nairobi City Park , 9 Feb. 2010, Malombe et al. CP-1563 ( EA) ; Mutha Plains , Aug. 1938, Joana 7510 ( EA) ; French Mission Land , Nairobi District, elev. 5900 ft, June 1932, Napier 1879 ( EA) ; Kitui District, Yakaseva, Voo Location , elev. 2000 m, 24 Aug. 1968, Kimani 80 ( EA) ; Thika , below Thika Falls, N side of Thika River, elev. 4850 ft, 28 Jul. 1967, Faden 67517 ( EA) ; Nzaui Hill , Machakos, elev. 6000 ft, 18 Jun. 1966, Agnew et al. 8381 ( EA) ; Upper Imenti Forest, within Meru Municipality boundary, elev. 1740 m, 28–29 Jun. 1974, Faden & Faden 74/906 ( EA) ; Central Province, Embu District, Mount Kenya Forest , 0.4 miles below Castle Forest Station Rest House, elev. 6700 ft, 20 Dec. 1966, Perdue & Kibuwa 8304 ( EA) ; Eastern Province, Machakos District, Kibwezi , 1 Aug. 1971, Bally B 14207 ( EA) ; Nyanza Province, N Nyanza District, Forest in vicinity of Kakamega forest station, 21 Dec. 1967, Perdue & Kibuwa 9407 ( EA) ; Kakamega Forest , elev. 4000 ft, Jun. 1962, Kerfoot 3901 ( EA) ; S Nyanza, Kisii District, 12 km S of Kisii town , elev. 1780 m, 7 Apr. 1978, Plaizier & Breteler 1114 ( EA) ; Nyanza , Kisii District, ca. 16 km NEE of Kisii, elev. ca. 1900 m, 8 Nov. 1974, Vuyk & Breteler 187 & 188 ( EA) ; Kakamega District, Kakamega Forest, Ishiulu , S of Yala River, elev. 1550 m, 4 Dec. 1996, Kamau et al. 264 ( EA) ; Narok District, Central Division, ca. 1 km from junction of Masai Mara Game Reserve on way to Bomet Road , AIC Ole-Polos , elev. 1921 m, 20 Feb. 2007, Kimeu et al. KEFRI-427 ( EA) ; Narok District, Ilgeri , elev. 2225 m, 26 Feb. 1979, Kuchar 10685 ( EA) ; Masai Mara Game Reserve, Kerigodwa ( Esoit Oloololo Escarpment near SW corner), elev. 1750–1850 m, 18 Jul. 1978, Kuchar 9388 ( EA) ; Narok District, Loita Hills, ca. 3 km SW from Morijo Loita , elev. 2125 m, 15 Aug. 1977, Kuchar & Msafiri 7047 ( EA) ; Maasai Mara Game Reserve, Springhead region of Olaimutiek stream, W side of Siana Hill , elev. 1950–2150 m, 29 May 1979, Kuchar 11504 ( EA) ; 10 km Narok to Nairobi road, Narok, elev. 1970 m, 20 Aug. 1993, Kemei & Muasya 4 ( EA) ; Narok District, Abossi Hill, Trans Mara , ca. elev. 7100 ft, 2 Aug. 1961, Glover et al. 2329 ( EA) ; Mombasa, just N of Witu , 29 Jan. 1958, Verdcourt 2121 ( EA) ; Tsavo East, Voi , 30 May 1965, Agnew & Part 1 Botany 733 7 ( EA) ; Majoreni, Vanga District, Coast , Nov. 1929, Graham 2182 ( EA) ; Watamu , Nov. 1982, Simpson 1 ( EA) ; Kwale, elev. 800 ft, Aug. 1929, Graham 2033 ( EA) ; Kwale District, Buda Mafisini Forest , 8 miles WSW of Gazi, elev. 80 m, 21 Aug. 1953, Drummond & Hemsley 3934 ( EA) ; Kwale District, Shimba Hills , 1 mile from Kwale on way to Mombasa, elev. 1250 ft, 12 Nov. 1968, Magogo & Estes 1211 ( EA) ; Buda Forest , Kwale District, elev. 60 m, 7 Dec. 1975, Kokwaro 3926 ( EA) ; Tsavo National Park East, Mzinga Hill, elev. 750 m, 9 Apr. 1966, Gillett 17230 ( EA) ; Tana River Primate Reserve , elev. 30 m, 24 Jul. 1988, Luke & Robertson 1204 ( EA) ; Kwale District, Gongoni Forest Reserve , NE side, elev. 30 m, 2 Jun. 1990, Robertson & Luke 6360 ( EA) .

Figures

FIGURE 2. Peponium elgonense. A. Growth habit in the wild. B. Root. C. Fruit and male inflorescence on the same individual. D. Abaxial view of leaf. E. Adaxial view of leaf. F. Cross-section of fruit. G. Male flower. H. Female flower. I. Unripe fruit. Scale represents millimetres (short, thin lines) and centimetres (long, thick lines). Photographs: Neng Wei.

FIGURE 3. Peponium cienkowskii (female individual). A. Growth habit in wild. B. Adaxial view of leaf. C. Abaxial view of leaf. D. Female flower. E. Dissected female flower showing ovary, petals, style and stigma. F. Unripe fruit. Scale represents millimetres (thin lines) and centimetres (thick lines). Photographs: G.W. Hu.

FIGURE 4. Peponium vogelii. A. Growth habit of male individual in the wild. B. Adaxial view of leaf. C. Abaxial view of leaf. D. Flowering habit in male individuals. E. Male flower. F. Fruiting habit. G. Unripe fruit. H. Cross-section of fruit. Photographs: G.W. Hu.