150 THE PLANTS 



the touch, and of a bright red colour, except in places 

 exposed to the glare of the sun. 



The beauty of red algae is something exquisite, and 

 every collector will consider his trouble well rewarded 

 if he has been fortunate enough to collect some of these 

 lovely algae ; for "a thing of beauty is a joy for 

 ever." 



The organs of fructification of this great group are 

 essentially alike, and consist of asexual cruciate or 

 tripartite motionless spores, antherozoids, and a carpo- 

 gonium with a basal part containing the egg cell, and 

 a hairlike top, called the " trichogyne." The smaller 

 antherozoids adhere to the trichogyne, piercing its cell 

 wall ; and their contents, entering the trichogyne, fer- 

 tilize the egg cell. After this fertilization, a compli- 

 cated process takes place, the result of which is the 

 cystocarpic fruit, consisting of a globular mass of 

 spores, either borne free (Nemalion), immersed in the 

 tissue of the frond (Halymenia), or contained within 

 special conceptacles. These latter are the typical 

 cystocarpic fruits proper to the group of the Rhodo- 

 melaceae. Polysiphonia urceolata (Fig. 70), common 

 on the English coast, is a good example to show the 

 cystocarpic fruit. 



The Rhodophyceae, or Florideae, are found in all seas, 

 but they prefer the temperate and tropical regions. 

 Many of their genera have a limited, others a wide, 

 distribution, but it does not follow that the species of 

 these latter have also a wide distribution. It may be 

 so, but more often they are limited to smaller localities. 



An important group amongst the red algae is that of 

 the Corallinaceae, so called on account of the carbonate 

 of lime which they secrete and deposit in their cell 

 membranes, with the exception of the cells of the 

 reproductive organs and those in the joints of the 



