Experiments on the Control of Fertility of Fern Leaves in Sterile Culture

The production of sporangia on excised leaves growing in sterile culture has been studied in three species of ferns, Leptopteris hymenophylloides (A. Rich.) Presl, Todea barbara (L.) Moore, and Osmunda cinnamomea L. 2. A high concentration of sucrose in the culture medium favors the production of sporangia on leaves of all three species, although the nature of the response is somewhat different in each. 3. In sporeling leaves of T. barbara it has further been observed that the response is enhanced by an increased supply of inorganic nitrogen in the medium, as well as by substitution of Knudson's solution of inorganic salts for Knop's solution. 4. None of the sporangia reached maturity in culture. No spores were present in the sporangia, the contents of which remained at a premeiotic stage of development. 5. The differences in response of the three species and the relation of the observations reported here to earlier studies are discussed.