Rothmannia is a genus of flowering plants in the coffee family Rubiaceae, order Gentianales. The genus was described in 1776 by Carl Peter Thunberg and named in honour of his fellow student Göran Rothman (1739–1778), a Swedish physician and botanist who, like Thunberg, studied under Carl Linnaeus.
The genus is native to tropical and southern Africa. Earlier treatments gave it a much broader range extending into the western Indian Ocean islands, southern China, Indo-China, and New Guinea, but molecular and morphological revisions have relocated those Asian members to other genera, principally Ridsdalea and Singaporandia. Modern circumscriptions therefore treat Rothmannia as an exclusively African group.
Within Rubiaceae — a family whose flowers are typically borne in multi-flowered inflorescences — Rothmannia is notable for its tendency toward solitary or few-flowered arrangements. This reduction in flower number tends to correlate with an increase in individual flower size, so several species produce conspicuously large, funnel-shaped blooms. Well-known members include Rothmannia globosa, Rothmannia capensis, and Rothmannia longiflora, a West African species bearing exceptionally long tubular white flowers that are pollinated by hawkmoths.
Etymology
The genus name Rothmannia honours Göran Rothman (1739–1778), a Swedish physician and naturalist. It was bestowed by Carl Peter Thunberg in 1776; both Rothman and Thunberg were students of Carl Linnaeus at Uppsala University.
Distribution
Rothmannia is native to tropical and southern Africa. Earlier classifications included species from southern China, Indo-China, the western Indian Ocean, and New Guinea, but these have since been transferred to other genera — principally Ridsdalea — leaving the genus restricted to the African continent.
Taxonomy Notes
Rothmannia was historically treated as a wide-ranging genus extending across the palaeotropics, but revisions have separated out the Asian and Pacific species into Ridsdalea and Singaporandia. The reclassification means the genus is now understood as strictly African within the tribe Gardenieae of Rubiaceae.
