BOTANICAL STUDIES ON SOME GENERA OF MIMOSACEAE AND CAESALPINIACEAE I- MORPHOLOGICAL AND ULTRASTRUCTURAL FEATURES OF LEAVES:

Taxonomic relationships between 4 species belong to 3 genera of two




fabaceous fami’ies; namely? Mimosaceae and Caesalpiniaceae were ¡dentified. These




species were; Leucaena Ieucocephala, Bauhinia varie gata, Bauhinia alba and Delonix




regia.




The objective of this study was to through the light on the taxonomic




relationships between these species by using leaf morphological characters and the




lamina surface characteristics (stomata and trichomes) under the Scanning Electron




Microscope (SEM). Single Linkage Clustering technique was applied to analyze these




characters to represent the relationships between the studied species.




Morphological description results indicated that both species of genus Bauhinia




and the species of genus Delonix are more close to each other in most of the studied




characters. The SEM on lamina surface is supporting the obtained morphological




results. A key includes morphological and SEM features studied was proposed.




INTRODUCTION




Bentham and Hooker, 1862 and Englar and Pranti, 1931(c.a. Shukia




and Misra, 2001) and many other taxonomists considered Caesalpinioideae.




Mimosoideae and Papilionoídeae as 3 sub-families of the family




Leguminosae under order Rosales. While, these sub-families are treated as




distinct families by many botanists (Heywood, 1993 and Pandey, 2004)




except those who cling to tradition. The authors are accepting the last point of




view as separate families based on vast diversity of fruits and certain other




characters. Hutchinson, 1969 (c.a. Pandey, 2001) has treated the 3 sub-




families under order Leguminaes.




Recently, the order Fabales includes 3 families; namely, Fabaceae,




Mimosaceae and Caesafpiniaceae (Pandey, 2004). The family Mimosaceae




(Acacia family), the smallest family of order Fabales; mainly tropical and sub




tropical trees and shrubs. It includes approximately 40 genera and 500-2000




species (Rendle, 1959). Leaves are often bipinnate and flowers regular with




petals valvate in floral bud, with 10 or more stamens. Mimosaceae can be




separated into 8 tribes on the basis primarily of the leaves nature and the




number and degree of the stamens fusion (Willis, 1973). In addition, some




classified it into 5 groups based on pollen type (Heywood, 1993).




The family Caesalpiniaceae (Cassia family) mainly tropical and




subtropical trees and shrubs. The family comprised of 133 genera and 2500m




3000 species (Rend le, 1959). Leaves are usually pinnate, but some times




bipinnate. Flowers are usually more or less irregular with lateral petals




(wings) covering the standard inside the floral bud, and with 10 or fewer