THE HIGHER CRYPTOGAMIA. 49 



for a very long time. It depends, certainly, only upon the 

 decay and internal disintegration of the buds. 



Blasia differs from all other leafy liverworts in the fact of 

 its producing these reproductive organs, but still more in the 

 fact that the well-known flask- shaped bud-ciips are formed 

 upon its upper side. 



The cell-multiplication of the terminal bud of Blasia very 

 much resembles that of Anthoceros, or of the young plants 

 of Pellia. The apical cell continues to divide repeatedly by 

 septa inclined alternately upwards and downwards (PI. VI, 

 figs. 19, 20). The cells of the second order divide by a 

 septum coinciding with the longitudinal direction of the 

 stem, and perpendicular to its surface. The frequent repe- 

 tition of the formation of these parallel septa in the two 

 halves of the stem causes the stem to increase rapidly in 

 width (PL VI, tigs. 17, 18). By the division of the cells of 

 the second order (and their daughter-cells) by septa parallel 

 to the surface of the stem, the stem increases in thickness 

 (PI. VI, figs. 19, 20). At the spot where a bud-receptacle 

 is about to be formed, this latter cell-multiplication ceases 

 at a very early period, even as early as in the cells of the 

 second order, whilst it continues in the neighbouring cells. 

 A circular depression is thus formed on the upper side of 

 the stem, close to its growing end, and quite covered by the 

 youngest superior leaves (PI. VI, fig. 20). Individual cells 

 of the base and sides of each depression send forth clavate 

 papillae, which are soon separated from the original cavity of 

 the mother-cell by a transverse septum (PI. VI, fig. 20). After 

 the apical cell of these short, hair-like papillae has divided 

 two or three times by transverse septa, the hemispherical 

 terminal cell divides by a longitudinal septum. In this 

 way a process of cell- format ion originates, which soon leads 

 to the production of a globular (or polyhedral) cellular 

 mass, viz., a reproductive bud, which is attached to the ' 

 above-mentioned depression in the upper surface of the 

 stem, by means of a hyaline stalk, consisting of one or two 

 narrow cylindrical cells, with clear fluid watery contents. 

 The arrangement of the cells of the reproductive buds cor- 

 responds with that of the terminal bud of the stem (PI. VI, 

 fig. 21). 



4 



