CabpoPhtTa. 151 



gone, but the actual entrance of the former has not yet 

 been seen. After fertilization the protoplasm in the car- 

 pogone increases considerably in size, and forms a cellulose 

 coat of its own. The cells which support the carpogone 

 send out lateral branches, which grow up and closely sur- 

 round it, finally covering it entirely (excepting the tricho- 

 gyne) with a cellular thick- walled " pericarp" {B, r). The 

 whole mass, including the fertilized carpogone and its in- 

 vesting pericarp, constitutes the simplest form of spore- 

 fruit (the sporocarp). 



311. The further growth of the spore-fruit takes place 

 the next spring by the swelling of the protoplasmic con- 

 tents, and the consequent rupture of the pericarp; the . 

 inner portion divides into several cells, C (the proper fruit- 

 spores), which give rise to zoospores closely resembling 

 those developed from the vegetative cells. From each 

 zoospore a new plant eventually arises. 



Practical Studies. — (a) These little plants occur in fresh- water pools 

 as little green masses adhering to leaves, sticks, etc. According to 

 Wood, we have probably two species. 



(b) The sexual process and the development of the sexual organs 

 eccui in May, June, and July. 



Class n. Floeidb^ {the JRed Seaweeds). 



312. The plants of this class, which are almost without 

 an exception marine, are among the most beautiful and in- 

 teresting members of the vegetable kingdom. All have 

 some shade of red or purple which sometimes becomes ex- 

 ceedingly rich; while for beauty of outline and delicacy of 

 branching they stand unrivalled among plants. 



313. To a great extent they grow in the deep water 

 below low-water mark, far beyond the reach of the ordi- 



