224 



INTRODUCTION TO CRYPTOGAMIC BOTANY. 



/ J. 



Fig. 57. 



a. Young frond of Macrocystis pyrifera, showing the mode of in- 

 crease. From a specimen gathered at Table Bay by Dr. Harvey. 



h. Fruit of M. pyrifera, var. luxurians, magnified, showing the spores 

 and their cells separating in different ways. From a sketch lent to me 

 by Dr. Hooker, The quadripartite division does not appear in this 

 section, but Dr. Hooker has observed it in others.* 



cation is only found in young plants, and consequently in such 

 as are attached to their native rocks. There the seeds will 

 find objects on which they may be attached, but it is evident 

 that they would be perfectly useless in the wide seas, a thou- 

 sand miles or more from land, and with a depth of a thousand 

 fathoms below them. The seaweed prairies of the tropics 

 are formed by species of Sargassum. " Macrocystis girds 

 the globe in the southern temperate zone, but not in the 

 tropics or the northern hemisphere." 



5. Sporochnace^, Harv. 



Inarticulate ; spores produced in jointed filaments, which 

 are free or compacted into little knob-like masses. 



209. A small tribe consisting of a few olivaceous seaweeds, 



* A young specimen from the Falkland Islands in fruit, given to me 

 by Dr, Hooker, is at first repeatedly dichotomous. 



