328 BOTANICAL GAZETTE [OCTOBER 
effective impurity of the laboratory air. Acetylene in sufficient concentra- 
tion has the same effect. In these impurities the seedling loses its negative 
geotropism and becomes transversely geotropic or diageotropic. All his con- 
clusions, with much more data for substantiation than NELJUBOW has, were 
reported by Knicut and his co-workers at the Boston meeting of the A.A.A.S. 
in 1910. Extracts of this report appear in Science®* and in the Experiment 
Station Record.3*—W1IL.LIAM CROCKER. 
Height of the Douglas fir.—Inquiring into the cause of the great height 
of the Douglas fir, Frye? finds that unusual size is a characteristic of many 
of its neighbors, and cites as an example the common brake, which in this 
region attains a height of 14 feet. This among other things leads to the sup- 
position that the cause of such giants of vegetation is to be sought in the 
climate, and hence to the conclusion that the fir is tall because it grows in a 
damp climate and in conditions of partial darkness due to overcrowding and to 
the large number of dark days during its elongating season —GeEo. D. FULLER. 
The chromosomes of Ginkgo.—Conflicting accounts by CARDIFF, 
CAROTHERS, and SpRECHER regarding the number of chromosomes in Ginkgo 
biloba led Isu1kawa3 to examine the readily accessible Japanese material. He 
found 12 bivalent chromosomes in the pollen mother cell, the number reported 
by Carprrr. One of the 12 is constantly larger than the other 11, a fact 
recorded in the figure but not in the text of both CARDIFF and CAROTHERS. 
While the paper is short, the evidence that 12 is the gametophytic number of 
chromosomes in Ginkgo is conclusive—CHARLES J. CHAMBERLAIN. 
The embryo sac of Pandanus.—From material of Pandanus coronatus 
collected in Java, CAMPBELL finds that the embryo sac has a nearly normal 
€gg apparatus, an endosperm nucleus formed by the fusion of two or more 
nuclei, and a considerable mass of antipodals, resembling the antipodal situa- 
tion in Sparganiwm, except that in Sparganium most of the. antipodals are 
formed after fertilization. CamppeLt had already noted as many as 14 
nuclei in the embryo sac of Pandanus before fertilization —CHaRLes J. 
CHAMBERLAIN. 
* Knicut, Lee I., Rose, R. Cairn, and Crocker, WILLIAM, Effect of various 
gases and vapors upon etiolated seedlings of the sweet pea; a new method of detecting 
traces of illuminating gas. Science N.S. 31:635, 636. Igro. 
* Exp. Sta. Rec. 23: 229, 230. 1910. 
* Frye, T. C., Height and dominance of the Douglas fir. Forestry Quart. 8: 
468-470. IgI0, 
3 IsHikawa, M., Ueber die Zahl der Chromosomen von Ginkgo biloba L. 
Bot. Mag. Tokyo 24:225, 226. Sigs. 3. 1910. 
4 CAMPBELL, D. H., The embryo sac of Pandanus coronatus. Bull. Torr. Bot. 
Club 38:293-295. 1910. 
