On the Development of the Spores of Riccia glauca. 
BY 
RUDOLF BEER, F.L.S. 
With Plates XXI and XXII. 
T HE principal facts in the development of the spores of Riccia have 
already been described by Leitgeb 1 and Strasburger 2 . In the 
seventeen years which have elapsed since Strasburger’s paper was written 
botanical microtechnique has, however, made such immense progress that 
it was thought desirable to subject these spores to a renewed investigation. 
Quite recently Garber 3 has dealt with the life-history of Ricciocarpus natans , 
and Lewis 4 with the embryology and development of Riccia lutescens and 
R. crystallina , but neither of these authors has described the spore or the 
development of its membranes. 
Lewis’s observations show that Riccia lutescens is merely a terrestrial 
form of Ricciocarpus natans , and he believes that the differences which 
exist in the structure of the thallus and the arrangement of the sexual 
organs are not sufficiently marked to justify the genetic separation of 
Ricciocarpus from Riccia. He accordingly drops the genus Ricciocarpus 
altogether and includes Ricciocarpus natans among the Ricciae. 
The material for the present study was fixed in strong and medium 
chrom-acetic mixtures (Chamberlain’s formulae), strong Flemming’s solution 
and in alcohol and acetic acid mixture. Of these the stronger chrom-acetic 
fluid proved the most satisfactory, but excellent results were also obtained 
with the alcohol and acetic mixture. 
I will begin my account with the fertilization of the egg-cell. The 
general character of this process is shown in PI. XXII, Fig. 28, from which it 
will be seen that it closely resembles the fertilization of Riccia ( Ricciocarpus ) 
natans as described by Garber. My photograph also shows that the shrinkage 
1 Leitgeb, Ueber Bau und Entwicklung der Sporenhaute. Graz, 1884, pp. 39-49. 
3 Strasburger, Ueber das Wachsthum vegetabilischer Zellhaute. Histologische Beitrage, Heft 2, 
1889, pp. 104-n. 
3 Garber, The Life-history of Ricciocarpus natans. Bot. Gazette, vol. xxxvii, 1904, pp. 161-77. 
4 Lewis, The Embryology and Development of Riccia lutescens and Riccia crystallina. Bot. 
Gazette, vol. xli, 1906, pp. 109-38. 
Annals of Botany, Vol. XX. No. LXXIX. July, 1906.] 
