No. 483] 



STUDIES OF THE OPHIOGLOSSACE.E 



147 



place at a very early period, and at this time the fertile spike is 

 already evident as a conspicuous protuberance on the adaxial 

 side of the leaf rudiment not far from its apex. Both divisions 

 of the young sporophyll terminate in an apical cell, and both 

 apparently grow in the same way. 



Fig. 5, A, shows a nearly median section of a very young 

 sporophyll of 0. pendulum. This is a broadly conical body upon 

 whose inner (adaxial) face there is a slight prominence (Sp.) the 

 apex of the young spike. Fig. 5, B, 



shows an older, but still very early ^ ^ 



stage, in which it is evident that the 

 spike rudiment extends completely to 

 the base of the young leaf , with which 

 it is adherent except at the extreme 

 tip. The apex of the young spike is 

 directed upward and its axis is almost 

 parallel with that of the sterile leaf 

 segment. From Bower's figures of 

 corresponding stages in 0. vulgatum 

 it is clear that a very similar condition 

 of things prevails in that species. In 

 such a stage as that shown in Fig 5, 

 B, the relation of the fertile and sterile 

 segments is not un]ik(> tliat of a stem 

 apex and leaf, and the conditicMi of 

 things here present would \ery well 

 lend itself to the intci pretation of a 

 terminal spike widi a sulitending ster- 

 ile lamina. At this stage the vascular 

 bundles are not yet difi'ereiitiated, and 

 the arrangement of these in the young 

 leaf still remains to be made out. 



the temperate zones, both the fertile 



and sterile segments of the leaf as is well known, except i 



