Variation in Blaeria spicata (Ericaceae)

Abstract

The taxonomy of Blaeria spicata Hochst. ex A. Rich. from Ethiopia and Jebel Marra has been investigated by Pichi-Sermolli & Heiniger (1953). They have suggested that the Jebel Marra material might be infraspecifically distinct because of its more robust habit, a more densely glandular pubescent stem, a tendency for the upper leaf surface to be more sparsely minutely pubescent and its shorter staminal appendages. They were unable to make any taxonomic decision on account of intermediate forms amongst the limited material examined. Now that more material is available from Jebel Marra it has been possible to reassess their observations. The average of three measurements were taken for the length of calyx, corolla, and style, using dry herbarium material. The presence or absence of branched, non-glandular and simple glandular hairs on the leaves and calyx, and the minute pubescence on the leaf, plus the length of the staminal appendages were also scored. Dendrograms were constructed for the three linear measurements, plus that of the ratio of calyx to corolla length (Fig. I, p. 512). The range of variation was similar for both the Ethiopian and Jebel Marra specimens. The other character differences noted by Pichi-Sermolli & Heiniger were confirmed, plus the additional observation that branched hairs on the calyx were either absent or sparse in many of the Jebel Marra specimens; intermediate forms were also observed, and one specimen, Jackson 2597, was identical with Ethiopian material. A scatter diagram was also constructed to see if there was any significant correlation between the different characters, or if any discontinuous variation existed. No such relationships were found, consequently the Jebel Marra material is not considered worthy of infra-specific rank. Oliver (1877) gave the distribution of B. spicata as Ethiopia, Cameroun Mountain, Fernando Po and Kilimanjaro; the latter locality is obviously due to a misidentification and the citation is such that the specimen cannot be positively identified. Engler (1892) referred the West African specimens to B. spicata var. mannii and later revised his opinion (1909) raising the variety to specific rank. Ross (1963) has maintained B. mannii (Engl.) Engl., into which he has sunk B. tenuipilosa Engl. ex Alm & Fries pro parte quoad specim. Ledermann 1625 and B. nimbana A. Chev. The involved taxonomic history of B. tenuipilosa has been discussed by Pichi-Sermolli & Heiniger (1953)Alm & Fries (1924) cited three syntypes for B. tenuipilosa; Ellenbeck 1814 (Bt) from Ethiopia was first so named but not described by Engler (p. 744, (1906)). Pichi-Sermolli & Heiniger have consequently erred in citing this specimen, which is based on a nomen nudum, as the holotype for the species.