Ferns and other higher cryptogams. If the publication of the volume has necessarily been delayed on this account, the superior character of the work is an ample compensation. The extent of the additions that have been made to our knowledge of the ?ora of the State during the past four years may be seen by reference to the many pages devoted to them. These addi tions are due to the interest and efforts of a comparatively few individuals, to whom proper acknowledgment is given in connection with Professor Brewer's account of the botanical collectors that have visited or resided in California. There still remains ample opportunity for good botanical work at almost any locality among the mountains, hills and valleys of the State, to which it is hoped that these volumes may prove both an incentive and an aid. Having thus brought to a close a work which has been far more laborious and protracted than was ever anticipated, I here return my sincere thanks to all those who have patiently waited for it, as well as to those who have in any manner assisted in its progress.