igisl 



PETRY—OPHIOGLOSSACE, 1 E 



349 



immediately below. Lang (9) has given in detail the vascular 

 connections of the branches in five specimens of this species; he 

 concluded that "the chief vascular supply of the branch is derived 

 from a development of xylem adaxially to the subtending leaf trace." 

 This adaxial xylem is considered to be an extension of the margins 

 of the leaf trace, and therefore centrifugal in character. 



Botrychium lanceolatum var. cmgustisegmentum.—A single 

 branching specimen of this species was secured. The terminal 

 bud has been destroyed and the branch has arisen at a considerable 

 distance below. As shown by 

 fig. 2, the vascular system of 

 the branch connects with the 

 subtending leaf trace. After 

 the trace has been separated 

 from the stem stele for a con- 

 siderable distance, tracheids 

 appear on the adaxial side of 

 the protoxylem of the trace; as 

 shown by fig. 3, these are 

 definitely centripetal in origin 

 and occur in contact with the 

 protoxylem. The mass of 

 xylem formed in this way gives 

 rise to the branch stele, which 

 soon assumes the characters of 



the main stele. This differs from the general condition in B. 

 Lunaria, as described by Lang, in that the branch connection 

 arises from centripetal xylem of the leaf trace rather than from 

 adaxial extension of the centrifugal xylem. 



Botrychium ramosum. Two rhizomes of this species, each bear- 

 ing a single branch, were secured. In each case the terminal bud 

 has been destroyed and the branch has developed at a considerable 

 distance below. The vascular connections of the branches differ 

 greatly from that described above. 



Fig. 4 shows the vascular supply of the branch in the first of 

 these specimens. As the leaf trace swings away from the stem 

 stele, wings of primary and secondary xylem develop in the angle 



Fig. 3.— Detail of 1 

 endodermis; X157. 



