Water-conducting System of Symphyogyna

Abstract

THE gametophytes of the liverwort genera Hymenophyton, Podomitrium, Pallavicinia and Symphyogyna contain an internal water-conducting system, which is strikingly analogous to the xyleni of simple vascular plants. This system is composed of one or more strands of narrow diameter, elongate, thick walled, densely pitted conducting cells that are devoid of protoplasmic contents at maturity. The presence of this system was first noted by William Jackson Hooker¹ in Jungermannia (now Pallavicinia) lyellii. Leitgeb² pointed out that the cells of the strand were elongate, possessed oblique end walls and that the cell walls were considerably thickened and possessed close-set pores. Tansley and Chick³ reported that the contents of the cells of the conducting strand disintegrate during development and demonstrated that the strand is actually an efficient water-conducting unit within the thalli.