262 PRACTICAL BOTANY 



Each leaf has a single central nerve or midrib. 

 Turn back one of the leaves, and observe with a lens 

 the small scale-like ligule : note that the insertion of 

 each leaf is oblique. 



3. The rhizophores, long cylindrical branched 

 organs, which arise at the points of branching of the 

 obliquely ascending stem, and grow vertically down- 

 wards : note their frequent bifurcations. Two rhizo- 

 phores are formed at each branching of the axis, one 

 on the dorsal, and the other on the ventral side ; of 

 these only the latter is as a rule developed beyond 

 the first rudimentary stage. 



Remove a rhizophore, which has grown down so as 

 to reach the soil, and wash it : observe 



4. The delicate roots, which rise at the point where 

 the rhizophore touched the soil, and branch in a 

 monopodial manner : and though they often seem 

 to bifurcate it appears not to be a case of true 

 dichotomy. 



Observe further that many of the branches of the 

 stem may have a symmetrical arrangement of the 

 leaves close to the apex : these are the branches or 

 cones, which bear the sporangia : note that on these 

 cones 



i. The leaves are all similar to one another and of 

 small size. 



ii. That they are arranged in four symmetrical 

 orthostichies. 



iii. That, on turning the leaves back, one sporan- 

 gium will be disclosed in each case. On comparing 

 a number of sporangia which have been exposed in this 

 way, it may be seen that there are two sorts of them 



