Pinna Growth and Development in Relation to Venation in Nephrolepis Species

Aina Arinola Fajuke,A M Makinde,M.O Isa,F.A Oloyede

doi:10.15835/nsb9210038

Abstract

Growth and development of the pinna in three species N. cordifolia, N. exalta(i), N. exalta(ii) and N. furcans were viewed in the department of botany of Obafemi Awolowo University, IIe-Ife campus. The results showed that all the venation of the pinnae of the species consist of a mid-vein and 2 lateral series of dichotomous vein all of which terminate freely near the lamina margins. Because it seems their venation patterns are similar, this might be one of the reasons for grouping them into one genus called Nephrolepis Schott. The development and growth pattern of N. cordifolia and N. furcans was uniform and consistent, while that of N. exalta gave two forms as the young was represented N. exalta (i) and the matured as N. exalta (ii). The growth patterns showing variations in the mid-rib, fertile and sterile pinnae provided useful specific distinctions.

Highlights

Nephrolepis is a genus consisting of about 40 species occurring mainly in the tropics sparingly in the subtropic and only locally extending into the temperate (Friedrich, 2005)
Leaf base in Nephrolepis could be cordate in N. furcans or truncate in N. exaltata
DIC- dichotomously branched vein; MR- mid-rib; PV- primary vein; SV- secondary vein;TR- trichome; VE- vein ending in hydathode/sori;VI- vein; VT- veinlet; EPepidermal cell; DG- deep groove at the margin;ST- stomata

Summary

Introduction

Nephrolepis is a genus consisting of about 40 species occurring mainly in the tropics sparingly in the subtropic and only locally extending into the temperate (Friedrich, 2005). Ferns and the so-called ferns allies comprise about 3% of the vascular plant species. The venation of ferns provides a rich source of information for identification (Wagner, 1979). This could be free, dichotomous or reticulate. The leaflets or pinnae of Nephrolepis are simple, sessile, and small in size and possess a single median vein that fails to reach the apex. Such leaves are called microphyllous or microphylls (Pray, 1970). The leaves are spirally arranged and densely cover the branches as a whorled in Lycopodium species (Bhambie, 1965)

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