53 



the branches lower down, where the cell division is in a more ad- 

 vanced stage of development, they grow quite near each other and 

 are now separated by a wall. The apical cell is also divided later on in 

 this way. When these cell parts or cells, as we may now call them, 

 have reached a certain degree of maturity they all with excep- 

 tion of the top cell begin to grow out in their uppermost end into 

 two opposite branches lying in the same plane as the whole frond 

 (see the lowermost branches in Fig. 38 c). These new branches 

 again grow out to a certain length and then they divide quite 

 in the same way and so on. In Fig. 38 a we see the uppermost 

 part of a young stalk in about the same stage of development 

 as the last-mentioned side branches in Fig. 38 c ; and Fig. 38 b 

 shows a more advanced stage, where the side branches have grown 

 much longer but are yet undivided. In my material I have not 

 succeeded in finding the first beginning of the cell division in the 

 stalk, this at first being a long cylindrical cell with no walls at 

 all, but I have no doubt that this is performed quite in the same 

 way as mentioned above with regard to the side-branches. 



The ramification of the branches can take place several 

 times ; in an old frond I have found branches of the 4th order. 

 While the branching is very regular in the young specimens, as 

 the figure shows, the ramification in the older leaves is more ano- 

 malous, branches of the highest order being not formed every- 

 where (Fig. 38 d). 



At the same time as the side branches of the first order have 

 begun to divide, the top cells of each branch develop at their 

 apices rhizoid-like organs of attachment which Murray and 

 Boodle have called tenacula. These consist of a little cell (Fig. 

 38 e) ending in a broader, irregularly lobed disc, by means of which 

 the top cell of each of the inward bent branches fastens itself 

 to the cell-wall of the branch nearest above. Most of the apices 

 of the top cells touch the branches above even before the tena- 

 culum has grown out and this need only be quite short, but some- 

 times it happens that it does not succeed in coming into close 

 connection with another branch and then it can grow rather long 

 like a rhizoid (Fig. 38 /). To begin with it is only the top cell of 

 each branch which fixes itself in this way, forming a kind of edge 

 along the side of the frond, but later on in the older frond nearly 

 all the side branches of the second, third and higher order are 

 provided with tenacula at the top and fastened to other branches 

 (Fig. 38 d). In this way, in good accordance with what is well- 

 known in other Striwea-species, all the branches, loose at first, 



