1895.] Vegetable Physiology. 583 
VEGETABLE PHYSIOLOGY: 
What becomes of the Flagella ?—Some authors have insisted 
that the flagella of swarm spores are finally absorbed into the body of 
the spore, while others have maintained that they are cast off. Ina 
recently published paper embodying the results of many careful exami- 
nations (Ueber das Schicksal der Cilien bei den Zoosporen der Phy- 
comyceten) Rothert shows that both views are correct. In the second 
swarm stage of Saprolegnia and in the Peronosporeae the flagella are 
either cast off as soon as the spore comes to rest or soon after, or else 
they remain attached to the spore indefinitely, even after germination. 
In the first swarm stage of Saprolegnia, however, he found to his sur- 
prise that they are as uniformly drawn back into the body of the pro- 
toplasm, the withdrawal being slow at first and then quite rapid. In 
both cases, more especially in the former, the old flagella are strongly 
inclined to turn back on themselves and form fused loops, the reason 
for which is not very apparent. These loops are formed while the 
flagellum is attached to the spore or after it has been cast off and may 
occur in any part of it, the straight part of the flagellum being drawn 
back into the loop which becomes, thereby, little if any larger, but in- 
creases noticeably in thickness. These loops usually form within 1 to 
3 minutes after the spore comes to rest. The author believes the loop- 
ing movement is due to the vital activity of the flagellum, the subse- 
quent drawing in of the straight part being accounted for by surface 
tension. He points out that purely physical causes would leave the 
flagella straight, or cause them to swell, or make them contrdct into 
balls. While not committing himself to the view, it is suggested that 
possibly the flagella are formed out of a special cytoplasm existing only 
in small quantity, and that at the end of the first swarm stage of dia- 
planetic swarm spores this is carefully husbanded for future use. The 
observations were made on Pythium complens, on a member of an un- 
described genus nearest related to Phytophthora, on Saprolegnia mono- 
ica, and on an undetermined species of Saprolegnia, the spores being 
sown in hanging drops.—Erwin F. SMITH. 
Perithecial Stage of the Apple-Scab Fungus.—In Berichte 
d. d. bot. Gesellschaft XII, 9, pp. 838-342 R. Aderhold describes the 
1 This cea is edited by Erwin F. Poh, Department of Agriculture 
oo i 
