7.2 BOTANICAL GAZETTE | JANUARY 
also in both hybrids, The number of chromosomes in the sporophytes of all 
the forms is fourteen. In the sporogenous division immediately preceding 
the formation of the mother-cells in both hybrids and in the pure form Fill- 
basket, the chromosomes were associated in pairs which may be related to 
the chromatin rings of the succeeding heterotypic division, Spermatogenesis 
in the hybrids proceeds just as in the pure races, and no abnormal mitoses 
were observed; consequently, abnormalities and irregularities of nuclear 
divisions do not form the basis for the variations of these hybrids. It is 
suggested that a thorough study of the sporogenous divisions preceding the 
heterotypic division may afford some explanation of variation.— C. J. CHAM- 
BERLAIN. 
AN INTERESTING account of the reproductive processes in Araiospora is 
presented by King.” Zoospores are formed through cleavage with the aid of 
vacuoles, and the outer plasma membrane is the last connecting film rup- 
tured. The oogonium contains from 35 to 55 nuclei, which pass to the 
periphery simultaneously with the formation and fusion of patches of fine 
meshed cytoplasm in the center of the ooplasm. There is probably a general 
mitosis before the periplasm is differentiated from the ooplasm. A receptive 
papilla from the ooplasm pierces the antheridium and establishes the canal 
for the entrance of the sperm nucleus. There is no antheridial tube, the wall 
of the canal being of oogonial origin. This is a very interesting point, in 
which Araiospora appears to differ from all other oosporic Phycomycetes. 
The periplasm divides by anticlinal walls into hexagonal cells which invest 
the egg. The egg is uninucleate and a single sperm nucleus enters the 
ooplasm. These gamete nuclei approach in the central region of denser 
ooplasm and extend toward one another, later rounding off and lying side by 
side. They were not observed in process of fusion and this event, if it occurs, 
must be greatly delayed, for the pair may be found in the oldest oospores. 
The development and structure of the sexual organs indicates a closer rela- 
tionship of Araiospora to the Peronsporales than to the Saprolegniales.— 
B. M. DAVIS. 
THE REDUCTION of chromosomes, development of the embryo sac, and 
fertilization in Paris guadrifolia and Trillium grandiflorum have been investi- 
gated by Ernst.* The number of chromosomes in Paris is 24 in the sporo- 
phyte and 12 in the gametophytes, while in Trillium the numbers are 12 and 
6 respectively. Since the two genera are so closely related, it is suggested 
that the double number of chromosomes in Paris may be due to an extra 
splitting of the chromatinthread. At the equatorial plate stage of the hetero- 
typic division a second longitudinal splitting of the chromosomes is already 
7 KING, C, A., Observations on the cytology of Araiospora pulchra Thaxter. 
Proc. Boston Soc. Nat. Hist. 31: 211. 1903. 
18 ERNST, Avy Chromosomenreduction, Entwickelung des Embryosackes und 
Befruchtung bei Paris guadrifolia L.und Trillium grandifiorum Salisb. Flora 91: 
1-46. pis. 1-6. 1902. 
