Renealmia L.f. (Linnaeus 1781: 79)

Fischer, Eberhard, Killmann, Dorothee & Dhetchuvi, Jean-Baptiste M. M., 2023, The family Zingiberaceae in Rwanda with description of two new species of Renealmia, Plant Ecology and Evolution 156 (2), pp. 225-238 : 225

2. Renealmia L.f. (Linnaeus 1781: 79)

Notes.

The genus Renealmia comprises 82 species ( POWO 2023), 26 of which are found in tropical Africa. While a modern treatment for tropical America ( Maas 1977) and subsequent descriptions of new taxa ( Maas 1979; Maas and Maas 1987, 1990; Ospina and Pozner 2013) and revisions of critical groups ( Lima et al. 2018) are available, the African species are still in need of a revision ( Lock 1985). Important contributions have been the treatments for Flore du Cameroun ( Koechlin 1965) and Flore du Gabon ( Koechlin 1964). Dhetchuvi (1996) proposes six new species of Renealmia in his PhD thesis, which will be validated in a paper on the genus in Central Africa (Fischer and Dhetchuvi unpubl. data). Another six new species have subsequently been discovered during intensive research in the field and in major herbaria. One of these taxa, R. timmiorum , was collected on a joint field trip by the first author and the last author in Rwanda and thus the description could be written in more detail. A second new species was collected by the first author in the isolated Cyamudongo Forest. The four remaining species will be described in a forthcoming paper. Champluvier (1988) only lists R. congolana De Wild. & T.Durand ( De Wildeman and Durand 1899: 144) from Rwanda. However, this species differs from Renealmia susannae-katziae and R. timmiorum in the partial inflorescences (cincinni) with at least 4-8 flowers and the distinctly pubescent rachis. Renealmia congolana is now considered as a synonym of R. africana Benth. ex Hook.f. ( Hooker 1883: 24) (Fischer and Dhetchuvi unpubl. data). This taxon has not yet been recorded for Rwanda and the specimens cited by Champluvier (1988) represent mostly R. timmiorum . The majority of collections available consists of fruiting material, including the majority of species already proposed by Dhetchuvi (1996). However, their description will point out the existence of these taxa and may help to collect further material and to assess the conservation status. Important characters used in the description of Renealmia species are the leaves, the number of flowers in a cincinnus, the shape of the bracteole, the shape of the calyx and the fruit (including number of seeds). Generally, the flowers are rarely available and flower characters are therefore difficult to apply for comparison with other species. The two new species proposed in the present paper have fortunately been observed with flowers and their characters are included in the descriptions. The majority of Renealmia species in Africa is restricted to lowland rainforest. The two new taxa from Rwanda represent species of the genus that are occurring at the highest known elevations of up to 2003 and 2267 m.