52 HOFMEISTER, ON 



cells of the third order divide by septa parallel to the longi- 

 tudinal axis of the germinating spore, and cutting the side 

 walls at an angle of 45. In the outermost new cells of 

 the fourth order, vertical and radial septa are formed, and 

 then horizontal septa. In this way the spore, in the course 

 of a month, is transformed into an oval cellular mass, whose 

 longitudinal diameter is from three to five times the length 

 of that of the ripe spore. The outer membrane of the 

 spore, which expands considerably, surrounds the continually- 

 increasing cellular body for some time, until eventually 

 it bursts (PI. XI, figs. 32, 33) ; the remnants of it often 

 remain for a long time adherent to the base of the cellular 

 body (PI. XI, fig. 37). 



One of the basal cells of the germ -plant now grows into 

 a root with a thick wall and a narrow cavity, precisely simi- 

 lar to those which are developed by the perfect plant (PL 

 XI, fig. 35). All the cells of the upper surface of the germ- 

 plant, excepting those of the apex, protrude outwards in the 

 form of arched papillae. Ten days later the first leaves 

 sprout forth close under the apex of the germ-plant, placed 

 opposite one another on the stem at equal distances (PL 

 XI, fig. 37).- The arrangement of their cells shows that 

 their growth results from the repeated division of a cell of 

 the surface of the stem, by means of alternately inclined 

 septa at right angles to the surface of the leaf. The second 

 pair of leaves stands exactly over the first; the two other 

 rows of leaves of the older plants first appear at a later 

 period. The form of these earliest leaves (ovato-acuminate) 

 is moreover very different from the two-lobed closely-folded 

 later leaves. The terminal bud of the stem is situated 

 between the leaves, in the form of a blunt, conical protu- 

 berance (PL XI, fig. 38). In this bud also the grow r th 

 manifestly results from the division of an apical cell, by 

 means of alternately inclined septa. 



The small globular spores of Jwngermannia bicuspidata 

 have a brittle, finely granular, brownish outer membrane ; 

 they contain a mucilaginous opaque fluid (PL IX, fig. 1). 

 The cushion-like masses of Palmelleae which are usually 

 found under the patches of this liverwort afford a peculiarly 

 suitable substratum for the germination of the spores. As 



