THE ADULT SPOROPHYTE 



93 



Strands. Each of these strands may divide, or only one of them (fig. 60). In some 

 of the smaller species there are only three bundles in the petiole, and in these forms 

 there are no anastomoses of the bundles above the base. In the larger species these 

 branches divide further and the number of bundles in the section is greater. Thus, 

 each of the tw^o ventral bundles may divide again in the upper region of the petiole 

 so that a cross-section at this point would show^ five bundles, a large dorsal one 

 and two pairs of smaller ventral ones. A similar condition of things is found in the 



Fig. 59. 



A. Vascular bundle from an adult rhizome of Ophioglossum moluccanum. X150. 



B. Section of an adult root showing monarch vascular cylinder. X35. The shaded zone 



is occupied by the mycorrhiza. 



small species, O. californtcum. As sections are examined below the junction of the 

 lamina and the petiole, it can be seen that further forking of the bundles has taken 

 place preliminary to their entering the lamina itself. Some of the species have the 

 tissues of the petiole quite compact, others show a greater or less development of 

 lacunae or air-spaces in the petiole. 



THE ROOT IN EUOPHIOGLOSSUM. 



The early roots in O. moluccanum grow from a large tetrahedral apical cell 

 showing a fairly regular segmentation, much like that of the typical ferns; but the 

 root cap is not so well developed nor does it show as definite a stratification. In the 



G 



Fig. 60. 

 Nine of a series of sections of a young sporophyll of Ophioglossum moluccanum. sp, the sporangiophore. 



early roots the whole of the root cap seems to be derived from the outer segments 

 of the apical cell. In the later and larger roots there seems to be somewhat less 

 regularity in the segmentation and no sections were found which showed the apical 



