26 BOTANICAL GAZETTE [JULY 
berg. The summary is not quite complete, as no mention is 
made of the result which Borodin? obtained with spores of 
Polytrichum commune. He found that they were unable to 
germinate in darkness. The work of Miiller-Turgau3 on the 
germination of spores and the production of secondary protonema 
is also omitted. 
As regards the fern spores, the earlier investigators made 
the assertion that light prevents their germination, as is to be 
noted in the works of Senebier, Humboldt,+ Ingenhouss,5 and 
Treviranus.© More recent investigators, as Kaulfuss,’ Leszczye- 
Suminski,®? Merklin,9 Wiegand” and Hofmeister," intimate that 
light is one of the necessary conditions for germination, although 
no definite investigations in that line are mentioned. 
The first investigations of importance from the physiological 
point of view are those of Borodin.? He experimented with 
eight different species of ferns and found that in all cases light 
was necessary for germination, and that in the dark no burst- 
ing of the exine occurred. His experiments are lacking in one 
datum, since he does not state at what temperature the cultures 
were kept. As shown by my own investigations this is one of 
the most important points. Two years later Gdppert*3 succeeded 
in bringing the spores of Osmunda to germinate in the dark, 
but the temperature at which the cultures were grown is unknown 
tome. A year later, Schmidt, with cultures of the spores of 
Aspidium violaceus and filix-mas, confirmed the results previously 
* Historiska Data rérande var Kinnedom om Moss-sporens Groning. Helsing- _ 
fors, 1884. Rectorprogram. 
* Bull. de l’acad. imp. de S. Petersbourg, 12: 433-440. 1867. 
3 Arb. d. Bot. Inst. zu Wiirzburg 1: 47 5-499. 
* Aphorismen go. 
5 Versuche mit Pflanzen IT, 5. Abschnitt. 
<s Entwickelungsgeschichte der Farnkrauter. Bot. Zeitung 7: 17. 1849. 
2g Vergleichende Untersuchungen 78. 1851, 2 Ibid, § I. 
3Schmidt, Uber einige Wirkungen des Lichtes auf Pflanzen 21. 1870. Breslau. 
