This volume summarises our present knowledge of inductive interaction during early development of various groups of chordates. Embryonic development is mainly epigenetic, that is, each embryo arises through gradual organisation and emergence of its constituent parts and not by the unfolding of preformed structures. Development as far as the full development of the 'body plan' in the embryo is described. At the beginning of development, there is only very restricted spatial diversity, but as development proceeds the interaction of the different parts leads to ever-increasing spatial complexity of the developing embryo. Interaction starts between the different cell organelles of the oocyte and the, spermatozoon; it continues without interruption between the different parts of the very early embryo and also between the different tissues and organ anlagen of the developing embryo. The new hypothesis as to the nature of the inductive interaction, which is postulated here, is in good agreement with the experimental evidence presented and opens new possibilities for fruitful research into this basic concept of embryonic development.

Mosses are a major component of the vegetation in ice-free coastal regions of Antarctica. They play an important role in the colonisation of ice-free terrain, accumulation of organic matter, release of organic exudates, and also provide a food and habitat resource for invertebrates. They serve as model organisms for physiological experiments designed to elucidate problems of plant cold tolerance and survival mechanisms and for monitoring biological responses to climate change. This Flora provides the first comprehensive description, with keys, of all known species and varieties of moss in the Antarctic biome. It has involved microscopic examination of around 10,000 specimens from Antarctica and, for comparison, from other continents. All species are illustrated by detailed line drawings, alongside information about their reproductive status, ecology, and distribution. This is an invaluable resource for bryologists worldwide, as well as to Antarctic botanists and other terrestrial biologists.

Prepared on behalf of the U.S. Atomic Energy Commission.

Annotated selected list of floras and floristic works relating to vascular plants, including bibliographies and publications dealing with useful plants and vernacular names.