88 | Proceedings of Indiana Academy of Science 
of Trondle,* who mentions a rather unusual case of irregular conjuga- 
tion. An instance of deviation in form is shown in a paper by Pickett.’ 
Another instance is given by Weatherwax of branching, etc., under the 
conditions there numerated. So far, however, as the branching of 
Fig. 2. Spirogyra elongata x 400. 
Spirogyra is concerned, this has been known for many years. 
As Sachs* says, if one cuts up the long filaments of Spirogyra and 
the pieces are laid on wet peat, some of the cells put out branched 
colorless tubes, which behave like roots. In fact, somewhat similar re- 
sults take place, as Sachs says, in highly organized plants, as in the 
rooting of several shoots in many vascular plants; and the stimulus of 
contact in the development of structures, as in Cuscuta. So that branch- 
ing may be produced in Spirogyra not only from a diseased condition 
but also at times by injuries. 
The writer has observed another case of somewhat more -compli- 
1Troéndle, A. Ueber die Kopulation und Keimung von Spirogyra, Botanische Zeitung, 
1907, Bd. 65, p. 192. 
2 Pickett, F. L. Bulletin of the Torry Botanical Club, 1912, Vol. 39. 
3 Weatherwax, Paul. Proceedings of the Indiana Academy of Science, 1914, pp. 203- 
206. 
4Sachs, J. Vorlesungen tiber Pflanzen Physiologie Zweite Auflage, 1887, p. 40. 
