THE HIGHER CRTPTOGAMIA. 55 



two new nuclei make their appearance. The germinating 

 spore divides into two halves by a transverse septum 

 originating between the two nuclei. The same process is 

 repeated in one of the newly-produced cells ; in this way a 

 short, simple row of cells is formed (PL IX, figs. 17 — 25). 

 The terminal cell of the row swells to the shape of a head, 

 and divides by a longitudinal septum. From the continual 

 division of the terminal cells a small band of cellular tissue 

 is produced, similar to the second stage of development of 

 the germ-plant of J. bicuspidata (PL IX, fig. 26), and 

 which, as in that plant, produces lateral regularly-placed 

 hairs, hair-like roots on the underside, and finally, after 

 further development, perfect leaves at its apex (PL IX, 

 fig. 26). At the time of the first appearance of the latter 

 I always found the oldest hinder part of the plant entirely 

 dead. 



The spores of Radula comjjlanata are tolerably large, 

 globular, and clothed with a brownish-yellow exosporium. 

 In the fluid contents, which enclose numerous very small 

 chlorophyll bodies, a very well - defined large nucleus 

 is suspended (PL XI, fig. 16). Twenty-four hours only 

 after sowing the spores upon moist bark the greater 

 number of them begin to germinate ; some lie quiescent 

 for weeks, and then germinate suddenly. Two nuclei, 

 which are very prominent as light circular spaces in the 

 opaque cell-sap, appear in the place of the primary central 

 nucleus. Between them a septum is formed, dividing the 

 spore into two halves (PL XI, fig. 17). The division is 

 repeated in the newly-formed cells, but by septa at right 

 angles to the first septum (PL XI, fig. 18) ; four cells 

 having the form of quadrants of a sphere have now been 

 formed in the spore. Each of these divides, in the first 

 instance, by a septum either parallel to the first-formed 

 septum or perpendicular to it (PL XI, figs. 19, 20) ; the 

 four four- sided ones of the newly-formed cells divide by septa 

 cutting the last-formed septa at an angle of 90° (PL XI, 

 fig. 20 5,c ). The body which has been formed by the 

 division of the spore-cell, and which now consists of twelve 

 cells, four central and eight peripheral ones, has now a 

 well-defined cake-like shape. Henceforth, the multiplica- 



