Interspecific Separation Of Gnetum L. (Gnetaceae) Based On Macro And Micro Morphological Features

Abstract

The study confirmed the occurrence and distribution of two species of Gnetum (G. africanum and G. buchholzianum) in southeastern Nigeria. A new collection, Gnetum species, which is clearly distinguishable from the other two by the peculiar structure of its male strobili is reported. Macro morphological variation was observed in characters like leaf form, leaf margin, inflorescence type, fruit shape and colour. Entire and lanceolate leaves are peculiar to G. buchholzianum while bead-like inflorescence of the new collection distinguishes it from the other species. Morphometric features like length of leaf, length of internode and length of spike varied among the species. However, analysis of variance on these features showed no significant difference (P < 0.05) in their mean values. The species are hypostomatic with amphibrachy-paracytic type of stomata. Pollens are generally spherical and acolpate. Pollen fertility values were high in the three species with the new collection having the highest value of 96%. Though difference was observed in pollen diameter, the generality of micro morphological characters suggest close affinity of the species. These results are discussed with a view to providing good description and taxonomic separation of the species.

KEY WORDS: Gnetum, male-strobili, pollen, stomata, vegetative-character

Global Journal of Pure and Applied Sciences Vol.11(1) 2005: 23-29