THE HIGHER CRYPTOGAMIA. 85 



support for Nageli's assumption that these septa are turned, 

 not in two opposite directions only, but in several direc- 

 tions. 



With respect to the ramification of the Jungermanniae, 

 the books afford but little information. I find no mention 

 by any earlier observer of the difference, to which I have 

 called attention, between the true dichotomy of Metzgeria 

 and Aneura and the pseudo-dichotomy of Pellia. The re- 

 marks made by C. G. Nees v. Esenbeck, with respect to 

 the ramification of the Jungermanniae, have reference only 

 to the fully developed condition.* His statement that the 

 place of insertion of a branch in the principal axis is fre- 

 quently not determined by the position of the angle of the 

 leaf, in other words, that it is not found above the 

 median line of the next lower leaf, afford as much sup- 

 port to my conjecture that the normal ramification of the 

 leafy Jungermanniae is a true dichotomy, as does the 

 figure which Gottsche gives of a leafless subterraneous 

 shoot of Ilapiomitrium Hookeri divided into two branches 

 beneath the apex.f 



With respect to the development of the leaves of Junger- 

 manniae, Gottsche's important statement must be remem- 

 bered, that in Haplomitrium Hookeri the leaf, when quite 

 young and consisting of only a few cells, bears at its apex 

 (or when mnlti-angular at each of its angles) a clavate, bent, 

 retort-shaped cell, which, in a fully developed leaf consisting 

 of a great number of cells, is still found in the corresponding 

 position. \ This observation, once made, afforded proof 

 that the cell-multiplication in the leaf of Jungermannia is 

 not the result of a continued multiplication of one apical 



cell. 



The knowledge of the structure of the archegonia of the 

 Jungermanniae was, like that of the similar organs in the 

 mosses, first established by Hedwig. He figures the arche- 

 gonia as organs closed before impregnation, as open at the 



* ' Naturgeschichte Europ. Lebermoosc,' i (Breslau, 1833), 17. 



f 'Nova Acta,' A. C L., xx, pars i, t, xiii, f. 1. 



+ /. c, pp. 275, 276. 



' Theoria generationis,' Leipz., 1798, 164. 



