154 BOTANICAL GAZETTE [AUGUST 
1, Streaming of the cytoplasm, nuclei, and vacuoles up the sporangio- 
phore and out toward the periphery, forming a dense layer next the sporan- 
gium wall and a less dense region in the interior, both containing nuclei. 
2. Formation of a layer of comparatively large, round vacuoles in the 
denser plasm, parallel to its inner surface. 
3. Extension of these vacuoles by flattening, so that they fuse to form 
a curved cleft in the denser plasm; and, in the case of Rhizopus, the cutting 
upward of a circular surface furrow from the base of the sporangium to meet 
the cleft formed by these vacuoles, thus cleaving out the columella. 
4. Division of the spore-plasm into spores; in Rhizopus. by furrows push- 
ing progressively inward from the surface and outward from the columella 
cleft, both systems branching, curving, and intersecting to form multinu- 
cleated bits of protoplasm, surrounded only by plasma-membranes and sep- 
arated by spaces filled with cell sap only; in Phycomyces, by angles forming 
in certain vacuoles containing a stainable substance and continuing outward 
into the spore-plasm as furrows, aided by other furrows from the columella 
cleft and dividing the protoplasm into bits homologous with and similar to 
those in Rhizopus, and separated by furrows partly filled with the contents 
of the vacuoles that assist in the cleavage. 
rmation of walls about the spores and columella, and, in the case of 
aes the secretion of an intersporal slime. 
6. Partial disintregration of the nuclei in the columella.—CHARLEs J. 
«eae 
AN EXCELLENT ACCOUNT of the sexual processes in Plasmopara alpina 
Johans. by Rosenberg * adds another form to the list of Phycomycetes which 
are now receiving so much attention. 
Plasmopara conforms in all essentials to the condition in Peronospora and 
Albugo, The oogonium contains at first about forty-five nuclei, which num- 
ber is doubled by the first mitosis. All of these pass into the periplasm 
excepting one, which remains in the ooplasm near a coenocentrum. There 
is then a second mitosis, affecting almost all of the nuclei. The nucleus in 
the ooplasm divides, forming the female nucleus, which remains close to the 
coenocentrum, and a sister nucleus that passes to one side and breaks down. 
Thus proximity to the favorable conditions around the coenocentrum deter- 
mines the selection of the functional gamete nucleus here as in others of the 
Peronosporales and in the Saprolegniales. 
The antheridium contains at first about five nuclei, which are increased to 
ten or twelve by mitosis. One male nucleus is introduced into the egg and 
fuses with the female. 
Of especial interest are Rosenberg’s views on the significance of the 
mitosis in the oogonium and antheridium. The author considers these as 
7° ROSENBERG, O., Ueber die Befruchtung von Plasmopara alpina. Bih. Svensk. 
Vet.-Akad. Handl. 28:—. [1-20. gis. 2.] 1903 
