A New Species of Mitriostigma (Rubiaceae: Gardenieae) from Tanzania

Abstract

J. Lovett, whose remarkable talent for collecting new species of plants during his surveys of forest areas in Tanzania continues to increase our knowledge of the flora, handed me for naming a flowering gardenioid shrub apparently quite unlike any previously known. Study of Keay's (1958) revision of the African plants previously referred to Randia or Gardenia indicates that its closest affinity is with a species collected twice last century in Fernando Po but apparently never refound there, namely Mitriostigma barteri Hook. f. ex Hiern which more recently has been rediscovered in Cameroun. The details of floral morphology agree well, particularly the short rounded corolla-lobes overlapping to the left, anthers just included in the widened part of the corolla-tube, pollen grains in tetrads, shortly bifid stigmatic club, narrow calyx-lobes, and the inflorescences borne at successive nodes on one side only and alternating from one side to the other..The new plant differs in having a much longer purple corolla and red calyx, Mann describing those of M. barteri as brown and green respectively. Letouzey, however, on the field-note to his collection 11168 from Cameroun describes the corolla as red outside and rose inside, so even at this level the agreement is good. Later a second specimen, fruiting, was found in the Oxyanthus covers allowing completion of the description and just as this paper was completed, Prof. A. Borhidi of the Hungarian Academy of Sciences visited Kew with a collection of Rubiaceae which contained a second fruiting gathering.