Study of anatomy of the genus Hura L. (Euphorbiaceae)

Abstract

Anatomy of leaf, wood and carpological structure of Hura L. was carried out with the aid of light microscopy. Useful taxonomic features for its delimitation and distinction are documented. Presence of scalariform perforation plates, narrow lumen and heterogeneous diameter are important features of the vessels. Laticiferous canals were found in the parenchyma tissue of petiole and midrib; where it occurs as a series of circular- to polyhedral-shaped cells. In the fruit peduncle, the ground tissue has some inclusions. Typical paracytic and anomocytic stomata of the Euphorbiaceae were recorded in the genus. The amphibrachyparacytic stomatal type found on the abaxial surface may be diagnostic. The range of interstomatal distance between any two paracytic and amphibrachyparacytic stomata is 35-45μm and 100-160 μm respectively. In between the cells, the former type has 2 cells whereas it varies from 5-6 cells in the latter. Glandular trichomes were restricted to the abaxial surface of the epidermis. Scalariform perforation plates in the wood link the genus to subfamilies like the recent Acalyphoideae, old Crotonoideae and Phyllanthoideae. Apart from this, other characters of the ground tissue and foliar epidermis offer strong support for its inclusion in the current subfamily Euphorbioideae. Since taxonomic description of this genus is lacking in the Flora of West Tropical Africa, published data on morphology from several sources and the present anatomical data are provided to fill this gap in knowledge.

Keywords: Anatomy, Euphorbiaceae, Hura, Huraea microscopy, taxonomy.