168 CRYPTOGAMS 



the cone terminating the fertile shoot. Dissect the cone under the 

 lens. Note the peculiarly modified leaves : how many saclike folds 

 has each? Is the number constant? What is the nature of these 

 "folds " as determined by the contents ? Draw a diagrammatic longi- 

 tudinal section of one of the cone leaves, much enlarged. 



403 (Compound). With the compound microscope examine the 

 contents of the sacs. Draw. Allow some of the spores to dry on a slide, 

 and then, while viewing them through the microscope with a low 

 power, breathe out gently so that the moisture from the breath will 

 strike the spores. Describe the action seen, illustrating by diagrams. 



XVI. CRYPTOGAMS 



404. The plants to be described in the present chapter 

 are a few chosen from a very great number of forms, 

 making up a series which differs in many important re- 

 spects from the group of Phanerogams. Cryptogams on 

 the whole are smaller than Phanerogams. It is true that 

 the Ferns (cryptogamous plants) are a conspicuous element 

 of land vegetation almost everywhere, and in the warmer 

 regions attain to the stature of trees ; and that Seaweeds, 

 some of them of great size, hold exclusive possession of 

 the littoral rocks and the borders of the ocean bed. But 

 the great majority of cryptogamic forms are too small to 

 attract attention, and many are even too minute to be seen 

 by the naked eye. Although many of the Cryptogams, 

 both great and small, have a very varied life history and a 

 structure that is by no means very easy to understand, yet 

 as a group the Cryptogams are structurally simpler than 

 the Phanerogams. 



405. Viewing all cryptogamic plants together, we find 

 that they fall into a kind of series, which, if followed in 

 one direction, leads toward the general type of organization 

 found in Flowering Plants ; or, in the other direction, leads 

 toward the simplest microscopic forms. The series is, 

 however, a very imperfect one, broken by many gaps. 

 Next to the Phanerogams stand Selaginella (Fig. 353), 

 Lycopodium (Fig. 357), and similar plants, with stem, 

 leaf, root, and even structures answering to rudimentary 

 flowers. A little further removed come the true Ferns 



