INTRODUCTION 7 



In describing the heterosporous Vascular Cryptogams it is usual to 

 speak of the spores which give rise to the female prothallium and those 

 which give birth to antherozoids as ' macrospores ' and ' microspores ' 

 respectively. The first of these terms is doubly objectionable : firstly, 

 etymologically, the proper meaning of /xa/cpo's being not 'large/ but 'long ; ' 

 and secondly, from the close similarity in sound of the two terms, an 

 inconvenience, especially in oral instruction, which every teacher must 

 have experienced. Seeing that the correct and far preferable terms 

 megaspore and microspore are used by Berkeley, Areschoug, Carpenter, 

 and others, it is difficult to understand how ' macrospore ' can ever have 

 got into general use ; and these terms, together with megasporange and 

 microsporange, will be used in the following pages. For similar reasons 

 megazoospore is always used instead of 'macrozoospore.' 



The male organs of fecundation are so uniform in their structure 

 throughout Cryptogams that very little complication has found its way 

 into their terminology. The cell or more complicated structure in which 

 the male element is formed is uniformly known among Cormophytes as 

 well as Thallophytes as an antherid ; the fecundating bodies are almost 

 invariably naked masses of protoplasm, provided with vibratile cilia, 

 endowed with apparently spontaneous motion, and bearing the appro- 

 priate name of antherozoids or ' spermatozoids.' The former of these is 

 perferable for two reasons ; from its etymological connection with 

 antherid, and because the use of terms compounded from ' sperm' should, 

 for reasons to be detailed presently, be avoided for male organs. In only 

 two important groups, Florideae and Ascomycetes, are -the fecundating 

 bodies destitute of vibratile cilia and of spontaneous motion : in the 

 former case they are still usually termed ' antherozoids ; ' in the latter 

 ' spermatia,' and their receptacles ' spermogonia.' In order to mark the 

 difference in structure from true antherozoids, it is proposed to designate 

 these motionless bodies in both cases pollinoids ; the term ' spermogone ' 

 is altogether unnecessary, the organ being a true antherid. 



A satisfactory terminology of the female reproductive organs presents 

 greater difficulties, from the much greater variety of structure, and the 

 larger number of terms already in use. The limits we have placed to 

 the use of the term ' spore ' and its compounds require the abandonment 

 of ' oospore ' for the fertilised ovum or oosphere in its encysted state 

 (enclosed in a cell-wall), anterior to its segmentation into the embryo ; 

 and this is the most important change involved in the terminology of 

 the present volume. 



In devising a term which shall include all those bodies which are 

 the immediate result of impregnation, it was necessary to take two 

 points specially into account. Firstly, the term must be capable of 



