Meyen's Report for 1839 on Physiological Botany. 399 



ILIA. -—Report of the Results of Researches in Physiological 

 Botany made in the year 1839. By F. J. Meyen^ M.D., 

 Professor of Botany in the University of Berlin. 



[Continued from p. 177.] 



2. In the Cryptogams. 



M. Unger* has published an interesting treatise on the 

 structure and functions of the organs of fructification ofRiccia 

 glauca ; he first notices the anatomical structure of the folia- 

 ceous substance, and shows that the want of stomata is made 

 up for by the loose conjunction of the cells on the surface 

 (this formation of the upper cells is particularly evident in 

 Riccia crystallina, Meyen). Then follows the description of 

 the observations of the development of both kinds of organs 

 of fertilization ; but the first stages of their appearance have 

 not been observed, because, as M. Unger says, the proper 

 time was already passed. The sporiferous organs (called 

 Pistils, Meyen) always appear in a large air-cell, and are said 

 to arise by the conjunction of a group of parenchymatous 

 cells, which during their increase and enlargement form a 

 cavity in their centre, which exhibited only one opening out- 

 wards. This bottle-shaped organ lengthens its neck until it 

 reaches the surface of the thallus, and now the enlargement of 

 the lower part of the sporangium commences (which is formed 

 by the ovarium of the pistil). The contents of the sporan- 

 gium appeared first as a homogeneous, colourless, fluid mat- 

 ter, and as a granular substance ; this collected gradually in 

 the middle, and then appeared as contents of that cellular 

 tissue out of which the primitive cells of the spores are 

 formed. 



It appeared also as a general fact, that at the periphery 

 one layer of cells produces no spores in their interiors (here 

 also a similar case of cells as in the formation of pollen in 

 the anthers of the Phanerogams, M.). In the structure of 

 the spores, M. Unger confirms the statement that the outer 

 brown skin is not composed of cells, but is only a reticulate 

 deposition of cellular matter. 



The other organs of generation, the so-called anthers, were 

 not found in such great numbers ; they were dispersed, and 

 occurred singly. '^L'hey are said to consist in a regular sepa- 

 ration of the parenchymatous cells of the thallus : here also the 

 contents form a granular substance, which appears in the 



* AnatomischeUntersuchungder Fortpflangungstheile von Riccia glauca^ 

 Liniiaea, p. 1 to 17. 



