Anatomical and morphological studies in the Chenopodiaceae. III. The primary vascular system and nodal anatomy

Abstract

A study of the primary vascular system and nodal anatomy of 32 species of the family Chenopodiaoeae is reported. The results of other workers are integrated and hypotheses regarding probable trends in the evolution of the vascular system are advanced.

Basically, the family has a unilacunar node, and the structure of the primary vascular system is classified into three types by reference to the number of leaf traces at a node and their relationships with each other or with cauline bundles within the axis. The Kochia-Bassia type, which is characteristic of Kochia, Bassia, Malacocera, Threllceldia, Babbagia, Enchylaena, Suaeda, and Salsola, is the most primitive and these genera are considered to be closely related. The specialized articulated group, which includes Salicornia and Arthrocnemum, and the third group, the Rhagodia-Atriplex, are more advanced. The relationship between genera within each of these groups is discussed with reference to the vascular anatomy and other morphological features.