THE HIGHER CRYPTOGAMIA. 157 



further longitudinal growth, it presses together the neigh- 

 bouring cells of the ventral portion, which have multiplied 

 considerably during the development of the fruit-rudiment. 

 This is very remarkable in Punaria (PI. XIX, fig. 11). At 

 the same time, the fruit-rudiment penetrates by its lower 

 conical end continually deeper into the tissue of the arche- 

 gonium. 



The cells of the second degree which are formed by the 

 continually-repeated division of the apical cell, and whose 

 form is that of a flat semi-cylinder, divide by a radial 

 vertical septum. This division usually takes place before 

 the next division of the apical cell. ' The cells thus formed, 

 each of which has a three-sided basal surface, divide by a 

 septum parallel to the chord of the arc of the free outer sur- 

 face, into an inner eel] with a three-sided, and an outer one 

 with a four-sided, basal surface (PI. XIX, figs. 9, 10, 11, 11*, 

 22,22^Pl.XX,figs.l4,15;Pl.XXI,fig.2"^ c ;Pl.XXIII). 

 The undermost margin of each such septum extends a little 

 beyond the line of contact of the corresponding septum of 

 the next lower cell. The next cell-division is that of the 

 outer cells by a radial longitudinal septum. Then all the 

 outer and inner cells of the group formed by the division of a 

 cell of the second degree divide by horizontal septa, the 

 inner ones often sooner than the outer ones (PI. XIX, 

 fig. 10). In the simplest moss-fruits, such as that of 

 Phascum for instance, there ensues a repeated division of 

 the cells of the circumference by means of horizontal 

 septa, so that these latter cells appear only half as high as 

 those of the centre (PI. XXI, fig. 1, a). The cells of the 

 periphery now divide by diagonal septa, the outer ones 

 again by radial septa, and so on alternately, until the 

 entire thickness of the fruit-rudiment is attained. At the 

 same time division commences in the central cells of the 

 middle and lower portions of the fruit-rudiment by means 

 of septa parallel to the chord of the arc of the periphery, 

 alternating with radial septa. This division leads to the 

 formation of the string of elongated cells, which traverses 

 the axis of the seta (PL XXI, fig. 1). 



In mosses with more complex fruit, such as Funaria 

 hygrometrica, and Gymnostomum pyriforma, the division 



