148 TJmversity of California PuMioations in Botany \yo\.. 8 



cases, near the surface of the host plant but sometimes occur in the 

 middle layer. In vegetative condition the cells are from 80/x to 100/x 

 in diameter, the cell wall is thin and of equal thickness throughout, 

 while the chromatophore is thin and spread over the whole wall. 

 The wall becomes thicker and apiculate at the outer end as the cell 

 passes into the reproductive stages, the apiculate wall piercing the 

 outer cortical tissues of the host. Kjellman states that the contents 

 divide into a large number of closely packed zoospores which escape 

 through an opening formed by the dissolution of the wall at the tip 

 of the cell. These latter statements are evidently inferences because 

 he distinctly says that he had only dried specimens for examination. 

 In an authentic specimen of the host plant distributed by Kjell- 

 man, young cells of the Chlorochytrium were found nearly spherical 

 in shape, with uniformly thin walls, and with a chromatophore thin 

 and dotted with numerous large pyrenoids. These cells are about 

 SOju, in diameter. 



Upon examining various specimens referred to this species, the 

 conclusion has been forced upon us that there is some variety of 

 species and possibly even of genera among the Pacific Coast plants 

 referred to Chlorochytrium inclusum and it seems practically demon- 

 strated that no one of those accessible to us is clearly the plant of 

 Kjellman. 



Very little can be accomplished from the study of dried specimens, 

 but living specimens should be studied to obtain more exact informa- 

 tion as to structure and development. Our present knowledge, even 

 of the type, is so slight as to admit of little certainty, and Kjellman 's 

 statements as to the formation and emission of "zoospores" need to 

 be carefully verified. * 



On reexamining the various specimens referred to this species from 

 our coast, we are able to make only a few general statements. 



Freeman (1899, p. 186) describes a plant which he provisionally 

 refers to Chlorochytrium iiiclusum, but he found only vegetative 

 stages. It was endophytic in the blades of Constantinea suhiilifera 

 Setchell. In the Algae of Northwestern America (1903, p. 206), we 

 referred several specimens to the same species. Of these we may dis- 

 tinguish, at least, two very different kinds of endophytes. The first 

 kind includes what are probably species of Chlorochytrium, possessing 

 a single chromatophore with numerous starch centers, while the second 

 is made up of plants seemingly possessing neither chromatophores nor 

 chlorophyll and certainly devoid of starch. No. 290, N. L. Gardner, 



