New species of Cladoceras and Rutidea (Rubiaceae) from Gabon and Equatorial Guinea

Background and aims – During the preparation of the Rubiaceae - Pavetteae treatment for the Flore du Gabon, three new species were identified in the genera Cladoceras and Rutidea. Material and methods – This paper is based on examination of herbarium collections of the new species and their relatives. Normal practices of herbarium taxonomy have been applied.

Two of the species were also studied in the field. The conservation statuses of the new species were assessed following the IUCN Red List Categories and Criteria. Key results – The three new species are described and illustrated.

Cladoceras longisepalum sp. nov., occurring in Gabon and Equatorial Guinea, differs from C. leonardii by its longer corolla with a different indumentum, laxer inflorescence with distinctly pedicellate (vs sessile) flowers and fruits, and longer subulate calyx lobes which are the longest recorded in the genus. Rutidea viridiflora sp. nov. and R. wieringae sp. nov. are both endemic to Gabon. The former species resembles R. hispida but differs by its shorter and green corolla (vs white), and fewer-flowered inflorescences; the latter resembles R. lujae but differs by its inflorescences with fulvous rather than yellowish hairs, its corolla glabrous or sparsely hairy externally, and its leaves with 7–10 pairs of secondary veins.

Cladoceras longisepalum and R. viridiflora are assessed as Vulnerable (VU) and R. wieringae as Endangered (EN).