William H. Lang

Preliminary Statement on the Prothalli of Ophioglossum pendulum (L.), Helminthostachys zeylanica (Hook), and Psilotum, sp

During a recent visit to Ceylon and the Malay Peninsula the author found prothalli of Ophioglossum pendulum, and Helminthostachys zeylanica, as well as a single specimen, which there is reason to regard as the prothallus of Psilotum. As the examination of the material will occupy a considerable time, it has seemed advisable to give a brief description of the mode of occurrence and external morphology of the prothallus in these three plants, without entering into details of structure or discussing the phylogenetic bearing of the facts. The chief gaps in our present knowledge of the gametophytes of the more isolated living Pteridophyta concern the Ophioglossaceæ and Lycopodiaceæ, to which groups the prothalli described below belong.

Preliminary Statement on the Development of Sporangia upon Fern Prothalli

The observations recorded in this paper were made in the course of an investigation into the relation existing between variability in the fern plant and apogamy in the prothallus. This research was undertaken at the suggestion of Professor Bower, F. R. S., and has hitherto been conducted in the Jodrell Laboratory, Royal Gardens, Kew. To Dr. Bower and Dr. Scott I am indebted for valuable assistance and advice.