Comparative Leaf Epidermis of Monodora Dunal. (Annonaceae) From Central and Western African and its Taxonomic Value
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Date
2019
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Library and Publication Committe University of Ilorin Nigeria
Abstract
A comparative assessment of the leaf epidermis of seven species of Monodora from Central and Western African was carried out with the aid of light microscope and species’ affinities were shown with relationship polygraphs. The studied stomata and non-stomata characters yielded some outstanding taxonomic values leading to recognition of three groups that may equate infra-generic sections in the genus: Monodora angolensis and M. brevipes forming one group, M. myristica and M. tenuifolia forming the second group and, M. crispata, M.undulata and M. zenkeri as the third group. The quantitative characters overlap significantly but the discontinuity found within the values marks the species’ limit. On the average, epidermal cell number varies from 34±2 in M. myristica to 92±2 in M. zenkeri on the abaxial surface whereas on the adaxial surface, it varies from 18±1 in M. brevipes to 126±3 in M. undulata and, usually the cell size is slightly more than twice greater than the stomatal size in all the species except in M. tenuifolia. The only feature that is constant across the genus is hypostomatic leaves, while brachyparacytic stomatal type is a new record in the genus. With these epidermal features, the species can be distinguished and their identification can be based on the documented data even when the leaves are fragmentary.
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Keywords
Annonaceae, classification, epidermis, Monodoreae, statistics, taxonomy.