68 BOTANICAL GAZETTE [JANUARY 
follows, The protoplast of the Cyanophyceae does not differ essentially from 
that of other plant cells, having a nucleus and peripheral cytoplasm with 
chromatophores. There is always a single nucleus, organized as an independ- 
ent organ and consisting of a relatively faintly staining ground mass in which 
the chromatin is imbedded and a larger or smaller number of “central gran- 
ules” which are not found outside the nucleus. The nucleus differs from 
that of the higher plants (1) in the absence of a nuclear membrane,} (2) in 
the absence of nucleoli, and (3) in its form. The cytoplasm contains chro- 
matophores, oil drops, cyanophycin granules, glycogen, and vacuoles. The 
chromatophores contain chlorophyll, carotin, and phycocyanin. The product 
of assimilation is glycogen, starch not being demonstrable, and the cyanophycin 
granules represent reserved albumen. The membranes of the vegetative 
cells are not cuticularized but consist principally of chitin, while those of the 
heterocyst are mostly cellulose. There are innumerable small chromatophores. 
The oft discussed central body is a genuine nucleus. During mitosis a 
spirem is formed which breaks up into chromosomes, and the various phases 
bear so striking a resemblance to those of higher plants that the author 
dispirem. Threads resembling a spindle are shown in several figures. 
Protoplasmic connections between vegetative cells have been demonstrated 
in many cases. Chromatin is said to be a constant constituent of the cells of 
the bacteria as well of those of the Cyanophyceae, and Kohl believes that 
the two groups are very intimately related. —C. J. CHAMBERLAIN. 
Handbook of systematic botany. 
THE SECOND PART of Wettstein’s handbook,‘ which has just appeared, 
deals with bryophytes, pteridophytes, and gymnosperms; the remaining sec- 
tion, which is to treat of angiosperms, will contain the index and will com- 
; gans from the standpoint of comparative 
morphology are particularly instructive, as is also the plate illustrating the 
evolution of plants, from the algae to the angiosperms. Considering the able 
3No reference is made to the work of Lawson, who, in the BoTANICAL GAZETTE 
for May 1903, discussed the absence of the nuclear membrane in the Cyanophyceae. 
*WETTSTEIN, R. v., Handbuch der Systematischen Botanik. II. Band, Theil 1. 
oe pp- 160. I colored plate, figs. roo. Leipzig and Wien: Franz Deuticke. 1903. 
4 
5 Bor. GAZ. 32: 61-62. 1901. 
