Coccinia pwaniensis Holstein

Holstein, N. & Renner, S.S. 2010. Coccinia (Cucurbitaceae) gains two new species from East Africa, three new synonyms, and one new combination. Kew Bulletin 65: 435. DOI: https://doi.org/10.1007/s12225-010-9229-9

Type

Kenya, Coast Province, Kwale Distr., Buda Mafisini forest, [8 miles] 12.9 km WSW of Gazi, 80 m, ♂ fl., 22 Aug. 1953, R. B. Drummond & J. H. Hemsley 3953 (holotypus K, 3 sheets; isotypus EA).

Morphology General Habit

Plants dioecious, creeping or climbing, up to 3 m long

Morphology Branches

Fresh branches green, lignifying to a greyish brown to purplish brown bark

Morphology Leaves

Leaves somewhat coriaceous, shallowly to profoundly 3 (– 5) lobate, 2 – 10.4  ×  2.7 – 11.4 cm, lobes broadly triangulate to elliptic, tips acute, margin minutely dentate, upper lamina fresh green, tiny pustulate, nerves sometimes with tiny hairs, lower lamina glabrous, rarely with blackish glands at base, nerves prominent and towards the base with stiff erect hairs that can be quite reduced, then appearing wart-like or subglabrous

Morphology Leaves Petiole

Petiole 0.6 – 4.1 cm long, adaxial side glabrous or with short bristly hairs, abaxial side with indumentum as on the nerves

Morphology General Tendrils

Tendrils simple

Morphology Reproductive morphology Inflorescences Bracts Probract

Probracts lanceolate, 0.2 – 0.3 cm long

Morphology Reproductive morphology Flowers Pollen

Pollen prolate

Morphology Reproductive morphology Flowers

Female flower unknown Male flowers in racemes, sometimes accompanied by 1 – 2 solitary flowers, the peduncle 3.2 – 7.7 cm long and glabrous, pedicels of flowers in racemes 0.2 – 0.95 cm, pedicels of solitary flowers up to 3.8 cm long, bracts 0.1 – 0.15 cm long, receptacle tube obconical, green, glabrous, calyx teeth 0.25 – 0.35 cm long, subulate and erect, corolla pale yellow to pale orange-yellow, 1.7 – 2.6 cm long, lobes triangulate-elliptical, outside with few-celled hairs, inside with multicellular hairs, filaments 3, connected to a glabrous central column, anthers sinuate, forming a globose head, orange

Morphology Reproductive morphology Fruits

Fruit solitary, petioles at maturity 2 – 3.3 cm long, fruit shape oblong-fusiform, 6.2 – 8 cm long, 1.8 – 2.3 cm in diam., rarely (?) with an up to 5.5 cm long sterile apical tip, immature green with pale longitudinal mottling, at maturity becoming orange-red to scarlet-red with pale mottling

Morphology Reproductive morphology Seeds

Seeds grey beige, 6.5 – 7  ×  4 – 4.5  ×  1.5 mm (L/W/H), more or less symmetrical, broad ovate in outline, and lenticular

Distribution

Cocciniapwaniensis occurs in the Coast Province of Kenya and the Pwani region of Tanzania (Map 1). It is expected near Tanga and Dar es Salaam.

Ecology

Open, disturbed places in East African coastal forests and dry woodlands (Brachystegia sp., Julbernardia sp., Diospyros sp.); on sandy soil at 80 – 460 m altitude.

Conservation

The species appears confined to coastal forests, which are declining due to deforestation although they are legally protected (Burgess et al.1998). However, low botanical collecting activity does not allow the assessment of the conservation status of this species. Therefore we treat it here as Data Deficient (DD).

Vernacular

All Kidigo. Mnokonyoka (F. Magogo & P. Glover 493), Mtambaa (F. Magogo & P. Glover 315).

Note

Cocciniapwaniensis apparently hybridises with C. grandis. This is suggested by a population discovered by the first author in the Pugu Hills, UTM 37 M 0507657 9237464, 194 m, ♂ fl., 25 July 2009, N. Holstein, F. M. Mbago & D. Shikelango 102 (DSM, M), 103 (M), 104 (M), 105 (DSM, M). Comparison of chloroplast and nuclear DNA sequences of plants from this population with those of C. grandis and other species suggests that C. grandis is the female parent. C. pwaniensis differs from C. grandis in the male flowers being borne in racemes, instead of solitarily. The hybrid plants were in full bloom, but none of their pollen sacs were opened, indicating that the plants may be sterile. Non-dehiscence of the anthers was also observed in an artificial hybrid between C. grandis and C. hirtellaCogn. created in a greenhouse in Munich (N. Holstein 108 (M)). Cocciniapwaniensis was first collected in 1939 and described as Coccinia sp. B in the Flora of Tropical East Africa (Jeffrey 1967: 64). The diagnostic characters mentioned by Jeffrey were the numerous male flowers in a long raceme on a rather long peduncle and the species’ occurrence in coastal forests. In addition, the leaves are often 3-lobate with acutely lobed tips, the male flowers are usually bracteate, and the calyx teeth are erect and subulate. The epithet pwaniensis comes from the Kiswahili word “pwani” for “coast” and points to the habitat and distribution of the species. The label of F. Magogo & P. Glover 493 states that the Digo tribe believe the fruits to be poisonous and eaten by snakes. The DSM duplicate of R. Wingfield 2056 has a fruit with an exceptionally long apical tip without seeds.