CHAPTER II. 



LEAFLESS JUNGERMANNIiE. 



Pettia epiphylla, Aneura pinguis and multifield, Metzgeria 



furcata.) 



Amongst all the liverworts indigenous to Germany, 

 Pel Ha epiplnjlla has the largest spores. They are oval, 

 surrounded by a delicate, finely granular outer mem- 

 brane ; in the ripe state, as they escape from the opening 

 fruit, they are multicellular. They usually consist of four 

 cells, arranged in a single row, two of which are disc- 

 shaped and two hemispherical (PI. IV, fig. 1). Sometimes 

 one of the former is divided by a longitudinal septum, so 

 that the spore is 5-cellular (PL IV, fig. 2). The internal 

 cavity of the cell contains much chlorophyll ; the green of 

 which, appearing through the thin, pale-yellowish wall of 

 the capsule, imparts to the unopened fruit its dark colour. 

 The cell which constitutes one of the ends of the spore 

 contains a far smaller quantity of chlorophyll- granules than 

 the other cells. Prom it springs the first of the long root- 

 like papillae by which the plant is attached to its place of 

 support. The cell next to this divides by a longitudinal 

 septum a few hours after the spores have been sown 

 on moist earth, even if such division has not taken place 

 earlier ; the same process then follows in the neighbouring 

 cell, and frequently also in the cell opposite to the radicular 

 cell. Each pair of cells of the middle region of the germi- 

 nating spore is doubled by longitudinal division, taking 

 place principally in the direction of one of the transverse 

 diameters (of the spore). Some varieties occur throughout 

 the whole extent of the cell-multiplication caused by this 

 longitudinal division, which, however, have little influence 

 upon the ultimate form of the plant. The division begins in 

 the cells next to the rooting cell (PI. IV, fig. 3), sometimes 



