Cytological Studies on Nemalion l . 
BY 
J. J. WOLFE. 
With Plates XL and XLI and a Figure in the Text. 
W ITHIN the past half-century only four papers of broad scope 
bearing on the Florideae have appeared. The work of Bornet and 
Thuret (’67), and that of Janczewski (76), both models of their kind, 
presented clearly and exhaustively the external morphology of the sexual 
organs and the cystocarp. Antedating, however, critical cytological 
methods they left much to be desired. Schmitz (’83) attacked the subject 
in somewhat greater detail, but was misled by the cytoplasmic fusions 
so characteristic of the group. Attaching a deeper significance to this 
than the facts warranted, he believed that those fusions actually involved 
the nuclei, and that here we have a sort of £ double fertilization.’ This 
was, of course, confusing, as it left the group presenting anomalous con- 
ditions. Oltmanns (’98), reinvestigating the subject, reached the conclusion 
that only the cytoplasm is involved, and that the ooblastema-filaments 
of Dudresnaya , for example, simply graft a cell derived from the fertilized 
egg upon the auxiliary cell. The original nucleus of the auxiliary cell 
disintegrates, leaving the nucleus derived from the zygote, which by repeated 
division gives rise to the favella of spores. This condition of affairs is 
entirely in harmony with current views as to the significance of the sexual 
act. Sachs (74) had already extended the theory of ‘Alternation of 
Generations ’ to the Ascomycetes, the higher Chlorophyceae, and the 
Florideae. The results of Oltmanns go far toward establishing the correct- 
ness of this view, which holds that in these forms what may conveniently 
be termed the interval between the spore and the fertilized egg is homolo- 
gous with the sporophyte in higher plants. Before this can be regarded as 
established, however, a comparative investigation of the chromosome-rela- 
tions in the nuclei of this interval and of the vegetative cells remains 
to be made. 
It is not clear why, in view of the great number of cytological studies 
that have appeared in recent years, the Florideae have received so little 
1 Contributions from the Cryptogamic Laboratory of Harvard University. — LIX. 
[Annals of Botany, Vol. XVIII. No. LXXII. October, 1904.] 
