Secondary Root Hairs

Abstract

A number of the Commelinaceae (Tradescantia, Setcreasea, Palisota, Dichorisandra, Commelina, Rhoeo, Zebrina) and related monocots (Philodendron, Asparagus, Zea) were studied with special reference to root hair production. In addition to the well known primary hairs produced from the epidermis, there are secondary ones produced from the hypoderm in the older primary hair zone. The persistent hairs have heavy entangled walls, but have living contents. There is no secondary thickening in the stele.