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