1904] CURRENT LITERATURE 227 
and are usually curved; consequently it is possible to distinguish the paternal 
and maternal chromosomes during fertilization and during mitosis. At the first 
two mitoses in the fertilized egg the two chromatins appear grouped and bilaterally 
arranged on the spindle, but later the grouping disappears. There is a mingling 
of chromatin in the resting nuclei, but the characteristic chromosomes of the two 
parents can be distinguished during mitosis. The writer strongly supports the 
theory that the chromosome is a permanent organ of the cell—CHARLES J 
CHAMBERLAIN. 
Tue THEORY of the individuality of the chromosome is supported in a recent 
paper by RosENBERG,?" whose work on Drosera has already furnished consider- 
able evidence in favor of this view. In the resting nuclei of Capsella, particularly 
in the nuclei of the cells of the suspensor, the 32 chromosomes characteristic of 
the species can be counted without difficulty. ‘The same number was counted 
in the sporophytic mitoses, and 16 were counted in the pollen mother-cells and 
in the embryo sac. Further, 48 were found in mitosis in the endosperm. Mito- 
short thick chromosomes, which are more easily traced*into the resting condition 
of the nucleus than are the long filamentous chromosomes of the Fritillaria type. 
J. CHAMBERLAIN. 
Leavitt’ has published the results of an extensive study of root hairs. Two 
types are recognized. In one case any cell of the piliferous layer in the young 
fixed tissue may produce a hair, there being no specialization for this purpose. 
‘ type is characteristic of most Filices, of some monocotyledons, and of the 
cotyledons. In the other case special cells for producing hairs are cut off in 
very young piliferous layer by a peculiarly oriented cell-division. These 
Specialized cells the author calls “trichoblasts,” and they are characteristic of 
all Pteridophytes 
of the hypodermal layer, the short roundish or oval cells that 
gitudinal row with the elongated prismatic ones. It is singular 
references to literature the author has not included his own 
ars ago, in which the trichoblasts of Azolla were fully described. 
among other 
Paper’s of two ye 
mas Be” Si ak 
a 
* Ros 
Flora 93: 
23 
ae G., Trichomes of the Toot in vascular cryptogams and angiosperms. 
he Nat. Hist. 31:273-313. pls. 16-19. 1904. 
Toot hairs, cap, and sheath of Azolla. Bort. Gaz. 34:414-419. pl. 16. 1902. 
ENBERG, O., Ueber die Individualitat der Chromosomen im Pflanzenreich, 
251-250. figs. 7. 1904. 
