382 University of California Puhlications in Botany [Vol. 6 



genus; that Wright's species, though perhaps incompletely diagnosed, 

 should remain in the genus Chlorochytrium of Cohn, as pointed out 

 by West, and that Reinhardt's species from the Black Sea should also 

 be placed in the same genus but given different specific rank, and re- 

 named. I therefore propose the name Chlorochytrium Reinhardtii. 

 Moore (1900, p. 100) wrote concerning a plant found by him at Lynn, 

 Massachusetts, growing on Enter amor pha, which he reluctantly re- 

 ferred to Chlorocystis Cohnii. The plant is well figured and care- 

 fully described. If compared with that which seems now to be the 

 general concensus of latest opinions as to what are the most important 

 characters that should constitute the genus Chlorochytrium, Moore's 

 plant should be allied with that genus, but is unlike any described 

 species of the genus. I propose the name Chlorochytrium Mooreii for 

 the form. It has been distributed in Collins, Holden and Setchell, 

 Phycotheca Boreali-Americana (Exsicc), no. 565, as Chlorocystis 

 Cohnii (Wright) Reinh. 



There still remain several phases in the life-history of Chlorochy- 

 trium. Porphyrae to be worked out. At the time of collecting the 

 plant, the host, Porphyra, was nearing the end of its life-history, 

 that is, the majority of the plants were in the fruiting condition. 

 There are, however, a few plants of this species to be found at all 

 seasons of the year, and the basal parts of the old plants remain for 

 some time after the plant fruits. Probably the endophytic C. Por- 

 phyrae remains in these older parts over the season unfavorable for 

 growth and infects the newer generations as they appear. The plants 

 become completely embedded within the host and no tube is left 

 behind through which the gametes escape. There is but a single 

 chromatophore, at first covering only the posterior, outer part of the 

 cell. This increases in size, at times thrusting out projections some- 

 times becoming a network but finally practically always covering the 

 cell wall. In this earlier stage it resembles the chromatophore figured 

 by Reinhardt, the principal character upon which he founded his 

 genus Chlorocystis. C. Porphyrae differs radically in the method 

 of gamete formation from that described by Reinhardt in his account 

 of the Black Sea plant. The cell divides first into two equal parts, 

 then successively into four, eight, sixteen, etc., up to five hundred 

 or more, depending upon the size of the plant, which may be ex- 

 ceedingly variable; whereas in Reinhardt's plant the "zoospore" 

 formation is by free cell division. 



Miss Whitting's Chlorocystis Sarcophyci seems to follow the 



