Abstract
Histochemical techniques and electron microscopy have been used to investigate the nature of the oblique primary end-walls of the water-conducting cells (hydroids) of Dendroligotrichum dendroides. (Hedw.) Broth. The observed properties (weakly birefringent; IKI-H2SO4-positive; periodic acid/Schiff negative; toluidine blue O-negative) support the conclusion that these end-walls are the cellulose residue of a primary wall that has been hydrolysed during autolysis of the hydroids. The walls are now referred to as hydrolysed end-walls. The unhydrolysed lateral-walls appear to be protected from hydrolytic attack by lignin or a lignin-like compound within those walls. The similarities between the hydrolysed end-walls of the hydroids and the hydrolysed walls of vascular plant tracheary elements are discussed.