No. 596] NOTES AND LITERATURE 



503 



ure been the inspiration and largely furnished the basis for the 

 comparative studies that shortly followed. Lewis 2 in 1909 pre- 

 sented an investigation of Griffithsia Bornetiana which is in essen- 

 tial agreement with the conclusions of Yamanouchi that an alter- 

 nation of sexual and tetrasporic plants occurs. From the zygote 

 nucleus, containing 14 chromosomes, are derived the nuclei of the 

 carpospores. The tetrasporic plants have 14 chromosomes and 

 were assumed to come from carpospores. The first mitosis in the 

 tetrasporangium is a reduction division so that 7 chromosomes 

 enter the tetraspores and these were believed to produce sexual 

 plants. Lewis, however, held that the sporophyte generation was 

 represented by the sporogenous cells of the cystocarp and con- 

 sidered the tetrasporic plant to be a phase of an homologous 

 alternation of generations even though it was clear that the tetra- 

 sporic plant led up to the critical period of chromosome reduction 

 in the tetrasporangium. From a study of Griffithsia corallina 

 Kylin 3 questions the accuracy of the details of nuclear structure 

 and mitoses as given by Lewis and also his count of the chromo- 

 somes which in G. corallina appear to be as high as in Polysi- 

 phonia. Kylin describes and figures the reduction phenomena in 

 the tetrasporangium of Griffithsia in substantial agreement with 

 Yamanouchi and in an earlier paper gives a similar account for 

 Filiation id a virgata.* 



Extremely interesting are the results of experimental cultures 

 made by Lewis s through which fruiting plants have been grown 

 from sporelings established in the laboratory on oyster shells that 

 were then favorably placed in the sea. From carpospores of 

 l '" } !i-<'i>l'""io violacea 6 tot rasporic plants were developed and 23 

 sterile. Tetraspores of Griffithsia Bornetiana produced a total of 

 60 sexual plants (32 male and 28 female) and 15 sterile. Tetra- 

 spores of Dasya elegans gave 149 sexual plants (143 male and 6 

 female) and 139 sterile, the apparently large proportion of male 

 plants in the culture of this species probably being due to slower 

 maturing of the females. The sterile plants of these cultures were 



z Lewis, I. F., "The Life History of Griffithsia Bornetiana," Ann. of Bot., 

 XXIII, 639-690, 1909. 



3 Kylin, H., << Die Entwieklungsgeschichte von Griffithsia corallina 

 (Lightf.) Ag.," Zeitsch. f. Bot., VIII, 97-123, 1916. 



4 Kylin, H., "Studien iiber die Entwieklungsgeschichte von Bhodomela 

 virgata Kjellm.," Svensk. Bot. Tidskr., VIII, 1914. 



5 Lewis, I. F., "Alternation of Generations in Certain Floridece," Bot. 



LIII, 236-242, 1912. 



