On the internal bundles in the stem of Rumex patientia L.

Abstract

The inflorescence axis of Rumex patientia has bicollateral bundles whose internal phloems give rise to obcollateral, ob-bicollateral and amphivasal bundles. Sometimes two or three internal bundles lie in association with a single outer bundle. It is concluded that the presence of such bundles is an advanced character. Farther, the condition in Rheum, where the internal bundles lie detached from the outer ones, is easily derived from that in Rumex.