EUPHYCOPHYTA 



37 



1956). Here the adult can reproduce itself by akinetes, zoospores or 

 gametes. The motile zygospore either gives rise to a pseudocihate 

 stage or aplanospore, both of them ultimately developing to a 

 colonial condition known as the Placosphaera stage (this stage was 

 formerly placed in a separate genus, Placosphaera). Under condi- 

 tions of drought the cells pass into what is known as the Urococcus 

 phase, which suggests that species of the genus Urococcus are prob- 

 ably only stages in the life cycle of other palmelloid-like algae 



(Fig. 13). 



Chlorodendraceae : Prasinocladus {prasino, leek-like; cladus, 

 short). Fig. 14 



This is included here because it is an example of the tree-like or 

 dendroid habit. The genus is found principally in marine aquaria 



I 

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I 



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tig 14 Irasinocladus. A, B, portion of plant showing cell structure. 

 1-3= cells. C, portion of plant showing arrangement of cells at 

 branching. D, portion of plant with branches and living cell. (All 

 X 1600.) pjy = pyrenoidj w=nucleus, 5=stignia, c = chloroplast, 

 m — basal margin of terminal protoplast, hr - first branch, hr^ — 

 second branch, chi-ch4 = short chambers behind terminal cell at 

 times of division, ch^ being the earliest, / = minute remnant of 

 flagella, Cj, C2= bases of two cells, p = papilla, 0= overlap of 

 lateral wall, / = entire lateral extent of one chamber, ep — papilla 

 pointing upwards, he = basal cross wall, t^ t^ = tops of two cells. 



(After Lambert.) 



