1913] CURRENT LITERATURE 517 
Somatic chromosomes in Vicia.—For several years the structure of chro- 
matin has received intensive study at the laboratory in Louvain, and numerous 
papers have been published by Grécorre and his pupils. A recent paper by 
SHarp% deals with the somatic chromosomes of Vicia Faba. The most impor- 
tant feature of this paper is the investigation of the resting nucleus and very 
. early prophase. Even those investigators who believe in the individuality of 
the chromosome generally admit that they cannot find the individual chromo- 
some in the resting reticulum, but SHARP claims, apparently with good reason, 
that the chromosomes in many cases can be identified even in the resting 
nucleus. Some of the stages leading up to the splitting of the chromosome 
have been misinterpreted by previous investigators and important stages have 
been overlooked. The telophasic vacuolization of the chromosome, now _ 
found by everyone, often gives the impression of a longitudinal splitting, and 
such a splitting is frequently described; sometimes the vacuolization results 
in the formation of short spirals. By schematizing features like these, it is 
easy to fall into error. Whether the vacuolization has resulted in the simula- 
tion of a split thread, or in a spiral, SHARP finds that in prophase a simple 
zigzag thread is formed which gradually straightens and by axial vacuolization 
becomes split into the future chromosomes. Thus the actual splitting is later 
than some have supposed. The vacuolization which appears in telophase has 
nothing to do with any splitting of chromosomes. There are no chromomeres 
and no continuous spirems either at prophase or telophase. oe 
The paper is another strong argument in favor of the theory of the indi- 
viduality of the chromosome.—CHARLES J. CHAMBERLAIN. 
Phylogeny of Filicales.—In continuation of his studies of the phylogeny 
of ferns, Bower» has investigated the monotypic tropical American gents 
Metaxya, which is better known as Alsophila blechnotdes. Since this fern has 
suffered vicissitudes of terminology,” having been referred to P olypodium, 
Aspidium, Alsophila, and Amphidesmium, the suggestion was natural that it 
might be a synthetic type. Bower concludes that the species deserves to 
represent a distinct genus, and that it is phyletically in a more primitive pos 
tion than the true Cyatheae. He has also included with this study a general 
survey of other relatively primitive and related genera. In connection wit 
this comparative study, Bower has attempted to estimate the value of various 
characters for phyletic purposes; and especially “to see whether the position 
which the sorus holds relative to the margin of the sporophylll is not @ saa 
reliable feature, in ferns, at large, than it has commonly been held to - 
The conclusion of the whole matter is that, “so far as the value of the gene 
Sater 
*Suarp, Lester W., Somatic chromosomes in Vicia, La Cellule 29:297-32?. 
pls. fT, 2. 1913. a 
* Bower, F, O., Studies in the phylogeny of Filicales. III. On ieee ere 
certain other relatively primitive ferns. Ann. Botany 27:443-447: Pls. 32-34 
