Pinna Growth and Development in Relation to Venation in Nephrolepis Species

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.