THE HIGHER CRYPTOGAMIA.. 69 



less the result of the resistance of the almost contiguous 

 fore and hind lobes of the enveloping leaves, between which 

 the organ must develope itself. 



A very different state of things is presented in Junger- 

 mannia bicuspidata and divaricata, and in Frullania dilatata. 

 In these plants, and in the latter of them at a very early 

 period, the multiplication of the cells of the free upper 

 edge of the perianth ceases altogether. On the other hand 

 there ensues an active multiplication of the basal cells by 

 rapid and often repeated divisions, in Jimgermannia divari- 

 cata and cuspidata chiefly by horizontal septa, in Frullania 

 almost as vigorously by vertical septa (PI. VII, fig. 14 ; 

 PL VIII, figs. 1, 2 ; PI. XII, fig. 2). The cells of the free 

 edge of the perianth of Jimgermannia bicuspidata grow at an 

 early period into long teeth, with transparent contents and 

 thick cell-walls (PI. VIII, figs. 1, 2). The form of the organ 

 passes from that of an open basket into a cylindrical, and 

 thence into a clavate shape ; the converging teeth close the 

 opening over the half-ripe fruit. In Frullania dilatata the 

 perianth during development becomes more and more 

 distended (PL XII, figs. 1, 2). The mouth, a narrow 

 ring, is lifted up higher and higher, reaches the height of 

 the apex of the archegonium shortly after the completion of 

 impregnation (PL XII, fig. 3), and by the time of the 

 termination of the longitudinal growth of the perianth, is 

 carried about five times higher, by the continuous multi- 

 plication, and ultimately extensive expansion of the cells of 

 the base. At the time of the ripening of the fruit the 

 number of the cells of the free edge of the narrow mouth 

 of the perianth is not greater by one than at the first 

 appearance of the perianth out of the surface of the stem 

 beneath the archegonia, when it amounts to from sixteen to 

 twenty. In Alicularia scalaris the intercalary cell-multi- 

 plication extends from the basal cells of the perianth, 

 up to the tissue of the end of the stem which bears the 

 archegonia. At the time when the rudiments of the 

 perianth appear in the form of an annular border enclosing 

 the young archegonia, the end of the stem is slightly 

 convex.* During the growth of the perianth there ensues 



* See Gottscbe, 1. c, p. 325. 



