Studies on the leaf anatomy of Euphorbia III. The node

Anatomical studies of representatives of 11 groups of species of the genus Euphorbia , erected on the basis of leaf venation patterns, reveal the occurrence of 3 main types of nodal organization, viz. unilacunar 1-trace, bilacunar 2-trace and trilacunar 3-trace (in the majority of the species). In some instances, a deceptive multi-stranded condition is visualized if cleared leaves alone are studied. Euphorbia polygonifolia and E. peplis leaves have a variable vascular supply in the same plant, consisting of 2 or 3 strands in the former and 2 or 4 strands in the latter. No correlation was found between the type of node and either the habit and habitat of the plant or the leaf shape and size.