Anatomy of the Cone and Fertile Stem of Equisetum . 665 
the stele of which was about 2J mm., and in a smaller cone, H. Another 
cone, I, was cut serially into longitudinal sections. As regards Eqtiisetum 
palnstre , a cone which I shall term Cone A was cut serially from above 
the uppermost vegetative whorl into transverse sections ; serial sections 
extending to below the annulus were made of another cone, B. Of another 
cone, C, serial sections extending from below the annulus to a point just 
above the second whorl were made. Cone D, a very small and young cone 
of the variety polystachion , was also cut into serial transverse sections, the 
series including the uppermost whorl of leaves. Serial longitudinal sections 
through the base of a young cone were also made. 
In the case of E. limosnm a’complete young cone, A, was cut into serial 
transverse sections ; these extended downwards to the uppermost vegetative 
whorl, but did not include quite the whole thickness of the nodal xylem. 
The whole of a still younger cone, B, with the uppermost vegetative whorl 
beneath it, was cut up serially into transverse sections. Another series of 
transverse sections extended from below the uppermost leaf-sheath through 
the lowest five nodes of an older and much larger cone, C. For all the 
three species the results obtained were confirmed by numerous longitudinal , 
transverse, and oblique hand-sections through different cones. 
The Cones of E. arvense and E. palustre. 
The xylem in the cone of E. arvense is relatively much developed 
compared with that of the cone of E. limosnm ; E. palustre is intermediate 
in this respect between these two species. Taking first E. arvense we find 
that below the basal fertile whorl, but some little distance above the 
insertion of the annulus, the strands of xylem lose the appearance of typical 
internodal bundles of the vegetative region. The two lateral groups of 
metaxylem become united by a curved band of tracheides and the carinal 
canals begin to diminish in size. This curved band of xylem is several 
cells thick in a radial direction and its concavity at first faces outwards ; 
its ends, continuous downwards with the lateral bands of metaxylem, 
project like them slightly beyond and externally to the phloem. The 
latter also forms a slightly curved band, the concavity in this case facing 
inwards, so that the phloem lines the interior of parts of the pericycle. As 
we approach the fertile node the band of xylem straightens out and 
eventually it comes to form a band slightly curved in the reverse direction, 
so that the xylem assumes the same contour as the phloem and the stele 
generally. Meanwhile, the xylem of each bundle begins to narrow in 
a radial direction, though it may still be locally three to five cells thick. 
As a rule, too, as we approach a node the xylem of a bundle begins to 
spread laterally towards the xylem of its neighbours. Generally, many of 
the bundles of the cone of E. arvense become united in the nodal regions 
by the formation of fresh tracheides ; usually these develop in continuity 
