the Anatomy of the Cone and Fertile Stem of Equisetum . 435 
traces. Ihe same remark applies to the small gap in the xylem between 
the fifth and sixth traces of the fourth whorl of Cone B (cf. Text-fig. 4). 
It is characteristic of E. debile that a number of wide, long, paren- 
chymatous meshes either remain enclosed throughout the whole cone (in 
which case the persistent meshes fuse around the base of the vascular strand 
of the acumen) or are only closed at or just below the apex of the cone, at 
the level of insertion of the closely approximated, often partially concres- 
Text-fig. 5. Recon- 
struction of the stele of 
Cone c of E. debile. Axial 
xylem black ; traces and 
parenchyma white ; i.a., 
level of insertion of annulus, 
x 10. 
Text -fig. 6. Recon- 
struction of the stele of 
Cone D of E. debile . Axial 
xylem black; traces and 
parenchyma white ; /.a., in- 
sertion of annulus. x 10 . 
xylem black ; traces and 
parenchyma white. The 
broken line enclosing a dotted 
surface represents the outer 
limit of the phloem where 
the latter projects beyond the 
xylem ; i.a. level of the inser- 
tion of the annulus, x 26 f . 
cent sporangiophores of the uppermost whorl. Indeed, except in Cone D, 
some of the meshes persisting into the apical region originate below the 
cone and annulus (cf. p. 445). 
Only six fresh parenchymatous meshes originate within Cone A of 
E. variegatum. All of them remain unclosed, becoming confluent with 
one another and with two unclosed meshes arising below the cone and 
persisting through it. In Cone B of this species six meshes arose within 
the limits of the cone and only one, of the second order, was closed. In 
