Coccinia adoensis var. jeffreyana Holstein, 2015

Holstein, Norbert, 2015, Monograph of Coccinia (Cucurbitaceae), PhytoKeys 54, pp. 1-166 : 63-64

2 c. Coccinia adoensis var. jeffreyana Holstein var. nov.

Coccinia adoensis var. jeffreyana Type: Tanzania. Iringa, Mufindi District, Ngwazi, 8°30'S, 35°15'E, 1830 m, female, fl, fr, 25 Feb 1987, J.C. Lovett 1597 (Holotype: MO!, isotype: EA!).

Diagnosis.

This variety has affinities with Coccinia adoensis and Coccinia senensis . The abaxial side of the petiole and the lower leaf surface bears simple trichomes with long cells, which appear crumpled or articulate when dry. Most of the trichomes, especially on the nodes, exceed 0.8 mm (-1.2 mm), whereas trichomes of Coccinia adoensis var. adoensis and var. aurantiaca are shorter <0.5(-0.8) mm. The calyx lobe length often exceeds 2 mm (in contrast to other Coccinia adoensis varieties), but the lobes are not subulate or narrowly acute as in Coccinia senensis but rather linear or if narrowly triangulate, then not with a pointed tip.

Description.

Perennial creeper or climber. Stems up to 3 m, more or less densely covered with long (at least on the nodes> 0.8 mm, Figs 3a, 5c) trichomes that appear articulate when dry. Petiole 0.25-3.5 cm, subsessile to distinctly petiolate, with long patent trichomes. Leaves 3.2-10.5 × 2.6-12 cm, shallowly to profoundly 3- or 5-lobate, lobes triangular, ovate to elliptical, margin dentate, slightly serrate, apex acute to obtuse with apical tip. Upper leaf surface glabrous or with few trichomes, hyaline to white pustulate. Lower leaf surface more or less densely covered with articulate trichomes, rarely almost glabrous with white pustules on veins. Probracts up to 3 mm. Tendrils simple. Male flowers in racemes, often accompanied by a single flower or one solitary flower. Common peduncle 5-5.5 cm, with short articulate trichomes. Pedicel of racemous flowers 5-9 mm, with short articulate trichomes. Bracts up to 1 mm, caducous. Pedicel of solitary flower 2.2-7.8 cm, with short articulate trichomes. Hypanthium with short trichomes. Calyx lobes 1-3.5 mm, narrowly triangular but not subulate, erect. Corolla 1.1-1.65 cm, yellow, orange, to dark crimson with darker veins outside, lobes 4-7 mm. Color of filament column pink, anther head orange-yellow to orange, color of pollen sacs not seen. Female flowers solitary. Pedicel 0.6-1.7 cm long, puberulous. Ovary with short to long, articulate trichomes. Fruit size c. 2-6 × c. 1 cm long, elliptical, often with sterile apical tip ( “beaked”), glabrous, green with white spots when unripe, red when ripe. Seeds 4-5.5 × 3-3.5 × 1.5 mm (L/W/H), symmetrically obovate, face lenticular (Fig. 14a).

Phenology.

Flowering time: January-March, November, December.

Distribution.

Fig. 23. Malawi (Northern Region, Southern Region), Tanzania (Dodoma?, Iringa, Mbeya, Morogoro?, Singida), Kenya (southern Rift Valley Province). 1300-2600 m. Soil preferences unknown. With Dodonea viscosa ; under pines; in Eucalyptus plantation, highland grassland, in open woodland with Combretum sp., Grewia sp., Strophanthus emenii , Acacia tortilis , Tapiphyllum obtusifolium , Burttia sp., Cassia sp.

Etymology.

The epithet was chosen to honor Charles Jeffrey, who worked extensively on the Cucurbitaceae and the flora of East Africa.

Use.

Unripe and ripe fruits are reported to be edible (C.J. Kayombo 296, P. Kuchar 22631), roots taken to make stomach medicine (P. Kuchar 22631).

Vernacular names.

Kihehe: mtumbulansoka (W. Carmichael 171); Kinyaturu: mukunguhi (P. Kuchar 22631).

Remarks.

Morphologically, this variety closely matches Coccinia senensis (with rather short petiolate to subsessile leaves, and a Coccinia senensis -like indumentum), but it has the calyx lobes rather of Coccinia adoensis var. adoensis , with the lobe length being intermediate between Coccinia senensis and Coccinia adoensis var. adoensis . The sequenced specimens do not cluster with most other Coccinia adoensis haplotypes from East Africa or southern Africa, and lack the typical deletion of Coccinia senensis in the trn SGCU- trn GUCC intergenic spacer ( Holstein and Renner 2011b). A Coccinia adoensis var. adoensis -like collection (S.A. Robertson 1925) also clusters with this variety, but it lacks the long trichomes. Long trichomes also appear in populations of Coccinia grandiflora or Coccinia mackenii in higher altitudes or in areas with higher precipitation. The collections of this variety are distributed above 1300 m and thus receive higher amounts of rainfall, so the long trichomes could be an adaptation. On the other hand, very similar trichomes regularly occur in Coccinia senensis , sometimes short though, but that species does not occur in such high altitudes. As the collections of this variety differ from the “typical” Coccinia adoensis , but still belong to Coccinia adoensis , they are treated as a new variety.

The collection R.E. Gereau & C.J. Kayombo 3582 (K, MO; Coccinia adoensis 4 in Fig. 17) is morphologically inseparable from this variety, and the plastid haplotype clusters within East African Coccinia adoensis . This collection has a normal-sized corolla, and therefore seems to be fertile, which supports the hypothesis that the var. jeffreyana is not reproductively isolated from var. adoensis . This is also why the present author refrains from designating it as a paratype, namely in order to avoid confusion about the genetic definition of this variety.

Phylogenetically, it is uncertain whether this variety retains an ancestral morphology of the common ancestor of Coccinia adoensis var. adoensis and Coccinia senensis or whether the longer trichomes are homoplastic due to an adaptive nature or this is a case of incomplete lineage sorting. Given the strong impact of aridification caused by the ice ages, the ancestor of Coccinia adoensis and Coccinia senensis presumably survived during an arid era in more humid coastal “forests” and woodlands of East Africa, where it evolved to Coccinia senensis and Coccinia pwaniensis . Other morphs evolved in woodlands rather in the inland, and are now pooled as Coccinia adoensis . Interestingly, the distribution of Coccinia adoensis var. jeffreyana , Coccinia senensis , and the allied Coccinia pwaniensis (shares the subulate calyx lobes with Coccinia senensis ) is very similar to that of the Apocynaceae species Carvalhoa campanulata K.Schum. ( Leeuwenberg 1985), which suggests shared ecological preferences.

The collections from Singida occur in drier habitats than those from C and S Tanzania. Collections with an indumentum like Coccinia adoensis var. jeffreyana also occur in NE D. R. Congo (A. Taton 128, G. Troupin 570), but it is uncertain whether these are also genetically linked to Coccinia adoensis var. jeffreyana , so they are listed here under Coccinia adoensis var. adoensis .

Specimens examined.

(selection, in total: 26) Kenya. Rift Valley Province: Namanga, cultivated in Munich Botanical Garden, N. Holstein 125 (M) and 130 (M). Malawi. Northern Region: Mzimba Dist., 3 mi. W of Mzuzu at Katoto, J. Pawek 10404 (MO, WAG [WAG0234128]). Tanzania. Iringa: Ludewa district. Livingstone Mountains, E slope of Msalaba Mountain, above stand of Acacia abyssinica on foot trail from mission at Luana, 09°59'S 34°36'E, R.E. Gereau & C.J. Kayombo 3535 (DSM, EA, MO, NHT, PRE); Great North Road, Sao Hill, 61ml. S of Iringa, R. Polhill & S. Paulo 1722 (B, EA, P [P05621244], PRE). Mbeya: Nyassa Hochland, Station Kyimbila, A.F. Stolz 504 (JE, M, U, W). Singida: 8½ km along road from Singida to Sepuka, 04°46'35"S 034°40'00"E, P. Kuchar 23919 (MO, S [S08-12129]).