68 



ing threads. The single-celled plants often associated in thread- 

 like or variously-shaped clusters, and contained in a common 

 mass of mucus. Chiefly fresh-water plants. 172 



Multiplying by means of zygospores, which result from the conjuga- 

 tion of cells of apparently the same kind. Mostly minute plants 

 of a bright green or greenish-brown color. 169 



Multiplying by the union of cells of different kinds to form oospores 

 or carpospores. 



Fruit-producing body consisting of a simple cell whose contents, 

 after fertilization, are directly transformed into a single spore or 

 many spores. Plants commonly green or olive colored. 163 



Cystocarps, after fertilization, producing in the first place special 

 cells, in some of which the spores arc subsequently formed. 

 Most of the species also produce tetraspores for vegetative multi- 

 plication. Plants red or purple, rarely green or yellowish, mostly 

 growing in deep-sea water or below the line of low tide. 



FLORIJDE^ OR RHODOPHYCE^l. 



Fruit spores not in groups, but scattered singly over the frond. 



Tetraspores in fours. Some growing in fresh water, some marine. 



Small, thread-like or leaf-like. Po&PHTBAOlA 

 Fruit spores in groups or in cystocarps. 



Frond continuous, or not jointed throughout. 156 

 Frond jointed. 



Frond becoming hard and coral-like, with an incrustation of carbon- 

 ate of lime, fruit bodies immersed in the frond, or wart-like, or 

 external. Frond thread-like, round, or somewhat flattened. Fruit 

 spores produced in fours. CORALLINACEJB. 



Frond cartilaginous, or not gelatinous. 155 



Frond consisting partly of gelatinous matter. 



Frond consisting of a single stem-like row of cells with or without a 

 cortical layer of longitudinal threads, with dense whorls of bead- 

 like branches. Very slimy. Mostly growing in fresh water. 



BATRACUOSPERMEJC. 



