A Simple Method for Fixing, Dehydrating and Embedding Pollen Tubes Cultivated in Vitro for Optical and Transmission Electron Microscopy

A simple method to cultivate pollen tubes in a gelatin medium is presented. After the growth of the pollen tubes in the culture medium, they are fixed, dehydrated, and embedded in resin for ultramicrotomy. The method is easy and does not require the purchase of special materials beyond those needed for the usual techniques for studying biological specimens under transmission electron microscopy.     

A new Palaeozoic plant closely allied to Prototaxites Dawson

Three-dimensionally preserved coalified fragments recovered from upper Wenlock to Lower Devonian strata of the Welsh Borderland and South Wales are placed in a fourth genus of the Nematophytales Lang. It differs from Prototaxites only in its possession of internally differentially thickened tubes. The possible functions of the tubular and filamentous tissues are discussed in the context of the putative affinities and likely habitat (terrestrial or fresh water) of the new genus.