XXVIII.—The Stem-Endodermis in the Genus Piper

Abstract

The stem of the various species of Piper is characterised by its anomalous vascular structure. Medullary bundles are present throughout the genus, and there is, in addition, a modified type of secondary thickening. During an investigation of these features my attention was called by Professor Montagu Drummond to certain endodermal characters which appeared to be of considerable interest and which suggested that a more extended investigation was desirable.Reference to the literature showed that the few earlier investigators of the genus had concerned themselves mainly with the peculiarities of the vascular system. J. E. Weiss (18) made some general observations on the occurrence of the endodermis in the genus, but no mention of the genus is made in the comprehensive monographs by Kroemer (8) and by Mylius (10) on the endodermis, or in the writings of Van Wisselingh. It would appear therefore that no detailed investigation of the endodermis in the genus has been carried out, in the past.