SELAGINELLA. SPOROPHORE. 163 



the small scale-like Ligule. Note that the insertion of 

 each leaf is oblique. 



(3.) The Rhizophores, long cyclindrical branched 

 organs, which arise at the points of branching of the 

 obliquely ascending stem, and grow vertically down- 

 wards: note their frequent bifurcations. 



N.B. Two rhizophores 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 developed 

 beyond the first rudimentary stage. 



Remove carefully a rhizophore, which has grown 

 down so as to reach the soil, and wash it : observe 



(4.) The delicate bifurcating Roots, which rise at 

 the point where the rhizophore touched the soil. 



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 



(a.) Macrosporangia, which are of a green or 

 light-brown colour, and appear to be of rounded 

 tetrahedral form. 



(&.) Microsporangia, which are more nearly 

 spherical, and of a reddish-brown colour. 



Note in older cones that the sporangia are already 



M2 



