IXTRODUCTION 5 



so considered together in the linear series in which they come in the 

 book. The Phycomycetes approach the Algs (Chlorophyceae) very 

 nearly ; and the other groups of Fungi bear a relation to the Phycomy- 

 cetes which seems to negative any supposition of their independent 

 connection with algal forms. 



One other point had to be decided, whether to commence at the 

 bottom or at the top of the series. Had our purpose been to construct 

 theoretically a genealogical tree for the lower forms of vegetable life, the 

 former course must necessarily have been pursued, and in the laboratory 

 there is no doubt much to be said in favour of proceeding from the 

 simple to the more complicated types. But to the general student, ' from 

 the known to the unknown ' is a very sound principle. And, among 

 flowerless plants, not only are the higher types far the best known to the 

 ordinary observer, but they are also those about the life-history of which 

 we have the greatest certainty of knowledge. We have been confirmed 

 in our belief of the correctness of this decision by observmg that in the 

 last edition of Huxley and Martin's ' Elementary Biology ' these authors 

 have (in the zoological section) abandoned the ascending for the 

 descending order. 



The question of terminology is one of the greatest stumbling-blocks 

 to the student of cryptogamy. Not only are new terms being constantly 

 introduced, many of them quite needlessly or from an erroneous idea of 

 structure ; but some that are in continual everyday use are employed 

 in different senses by different writers of repute. The first requisite in 

 a terminology, after accuracy, is simplicity ; and to this end we have, 

 wherever possible, used anglicised instead of Latin and Greek forms. 

 Many of the terms which we employ throughout this volume — such as 

 sporange^ archegone, antherid, coenobe^ sckrote, epiderm, &:c. — will probably 

 be accepted at once ; and it seems strange that the awkward and un- 

 couth foreign forms of these words should have held their ground so 

 long. With others there will no doubt be greater hesitation ; but we 

 hope to see all, or nearly all, of the anglicised forms we have used gradu- 

 ally introduced into all English works on cryptogamic botany, and the 

 same principle possibly extended in other cases where we have not 

 ventured to apply it. 



A striking instance of the uncertainty which still surrounds crypto- 

 gamic terminology is afforded by the various senses in which different 

 writers use the everyday term ' spore.' Le Maout and Decaisne and 

 Asa Gray speak of spores as ' the analogues of seeds ; ' Berkeley de- 

 .scribes the unfertilised oospheres of Fucus as spores ; Vines includes 

 under the term all reproductive cells produced either asexually or 

 sexually ; while Sachs defines a spore as a reproductive cell produced 



