INTRODUCTION TO CRYPTOGAMIC BOTANY. 



183 



lusca for instance, so long as mere external characters alone 

 were regarded, genera of the most widely different structure 

 were constantly confounded, and mere analogies are every day 

 deceiving those who are content merely with the surfaces of 

 things. Still, in some cases, I am inclined to think that the 

 mere division of the endochromes is not sufiScient to authorise 

 a distant separation. Rhabdonia (Fig, 45, a) and Solieria (Fig. 

 44, e) are so circumstanced. The mere division of the endo- 

 chrome is certainly in many cases not of generic importance in 

 Fungi, and perhaps its importance has been exaggerated in 

 some cases where Algae of similar habit are concerned. 



Fig. 45. 



o. Portion of nucleus of Rhahdonia Oovlteri, Harv., magnified, show- 

 ing tlie separate cells, witli the dissepiments and spores, after Harvey. 



h. Portion of nucleus of Sphcerococcus coronopifolius, Ag., and single 

 spore, magnified. (DesmiospeemejE.) 



c. Spore-threads of Wrangelia penicillata, Ag., after Harvey. 



d. Tetraspores of Cruoria pellita, Pr., from a specimen gathered by 

 Mr. Ealfs, April, 1842. {Petrocelis cruenta, J. Ag.) 



158. Both the genera and species of this division have fre- 

 quently a wide range. The commonest of all red seaweeds 

 on our coast, and one of the most elegant, Plocamium cocci- 

 newm, is found all over the world ; while all the other species of 

 the genus, which, perhaps, have been too miich multiplied, are 



