MICROSCOPIC STRUCTURE OF HIGHER CRYPTOGAMIA 



331 



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CHAPTER VIII. 

 MICROSCOPIC STRUCTURE OF HIGHER CRYPTOGAMIA. 



327. FROM the simple Protophytes, whose minuteness causes their 

 entire fabrics to be fitting objects for Microscopic examination, we pass 

 to those higher forms of Vegetable life whose larger dimensions require 

 that they should be analyzed (so to speak) by the examination of their 

 separate parts. And in the present Chapter we shall bring under notice 

 some of tiie principal points of interest to the Microscopist which are 

 presented by the Cryptoyamic series; commencing with those simpler 

 Alga9 which scarcely rank higher than some of the Protophytes already 

 described, and ending with the ferns and their allies, which closely 

 abut upon the Phanerogamia or Flowering Plants. In ascending this 

 series, we shall have to notice 

 a gradual differentiation of or- 

 gans; those set apart for Repro- 

 duction being in the first place 

 separated from those appropri- 

 ated to Nutrition; while the 

 principal parts of the Nutritive 

 apparatus, which are at first so 

 blended into a uniform expan- 

 sion or thallus that no real dis- 

 tinction exists between root, 

 stem, and leaf, are progressively 

 evolved on types more and more 

 peculiar to each respectively, 

 and have their functions more 

 and more limited to themselves 

 alone. Hence we find a ' dif- 

 ferentiation,' not merely in the 

 external form of organs, but 

 also in their intimate structure; 

 its degree bearing a close cor- 

 respondence to the degree in 

 which their functions are re- 

 spectively specialized or limited 

 to particular actions. But this 

 takes place by very slow grada- 

 tions; a change Of external form A, Terminal portion of branch of Sphacelaria cir- 

 rvffon cl-irtwinn- if coif \\ o f r> v o rhosa ; B, lateral branchlet of S. Tribuloides, the ter- 

 )Iten SllOWmg Itsell, Dei Or e minal ' cel i of which is emitting antherozoids. 



there is any decided differenti- 

 ation either in structure or function. Thus in the simple Ulvcz (Fig. 

 144), whatever may be the extent of the thallus, every part has 



