HIDDEN MARRIAGES 



501 



faintest approach to a sexual union, 

 the term " nowerless " as applied 

 to the entire division of these 

 plants is somewhat inappropriate 

 and misleading. In many of the 

 groups the essential organs of 

 Phanerogams are represented by 

 antherids and archegones, and the 

 female element has to be fertilized 

 by the male before a true embryo 

 can be formed. 



Until recent years the term spore 

 was made to do duty in this division 

 as the name for bodies of widely 

 differing values, and the result has 

 been that much confusion is caused 

 in the minds of students. To-day 

 botanists proceed upon the more 

 sensible plan of giving distinctive 

 names to the body resulting from 

 special methods of fertilization, 

 in harmony with those used for 

 Phanerogams, restricting the use 

 of spore to those propagative 

 bodies that are produced without 

 fertilization. We shall adopt this 

 terminology in the main here. 



The vast majority of the Cryp- 

 togamic Plants are composed en- 

 tirely of cellular tissue. Scalari- 

 form tracheides are the most 

 frequent form of thickening in 

 the xylem, and sieve-tubes occur 

 commonly in the phloem, but true 

 vessels formed by the union of 

 cells are rare. 



Respecting the diversity in the 

 foliar organs of the Vascular 

 Cryptogams, Messrs. Bennett and Murray have given in a paragraph a 

 clear view of the principal types : " The size and form of the leaves are 

 extremely various. In Lycopodium, Selaginella, and some other genera, 

 they are very small, unsegmented, and lanceolate, not unlike those of 

 mosses, and form a dense imbricated clothing to the stem ; in Psilotum 

 they are altogether rudimentary; in the Equisetacese they are reduced to 



FIG. 637. HABD FERN (Lomaria spicant). 

 (a) Barren fronds. (6) Fertile frond. 



