EQUISETUMS AND CALAMITES. 89 
of the Calamite stem indicates clearly that, like the stem of most 
nating series, while in Misi the rays are continuous, and do 
not alter their position at each node. As to the infranodal canals, I 
would beg to suggest that they were the spots at which the extremely 
delicate tissue is formed which gives rise to the endogenously formed 
buds of Equisetums, and from which the branches and roots originate. 
In Equisetums the branches and roots arise close together at the upper 
end of the Saternade, but in Calamites the roots apparently spring 
from the lower end. 
necessary to be very guarded in pred new genera or peers from 
characters derived from the structure of the stems of Calamites. As 
sporangia, form an alternating vertieil of fewer leaves than the sterile 
one. Should this character be found to hold, it would be an admirable 
one by which to ra Calamites and Equisetums. The class Equise- 
tee is separable into two orders:—1. Equisetes ; and 2 Calami- 
tee. The Equisetex distinguished by having all the leaves of the cone 
modified and bearing bagi a while the Calamitese have only every 
alternate verticil bearing sporangia. 
I have said enough to direct attention to ie EL alaneey of 
sclerenchyma in these plants, and also to point out to h 
may take up this most interesting subject that the py mt - 
must be taken in the identification of the various tissues 
I Sige that those who have worked at the subject will ‘find that ° 
not eur ey nted them, and have only attempted se " 
Seeouha w t I believe to be the truth, while at the same time I 
not wish to heen or put forward the ‘slightest claim to infallibility. 
GeneRraL Conciusions. 
1. That or _ of Equisetum differs but little in construction from 
that of 
0. That fe mn be thE iset 1 Calamites the fibro-vascular bundles 
are but poorly developed. 
3. that the ae tissue (woody-wedges of Williamson) forming 
the most important part of the stem consists of the small fibro-vascular 
bundles, with the addition ofa large anes of thickened parenchyma 
and “grape ae (sclerenchyma, Mette 
That the sclerenchyma (ieteonins) is is part of the cortical tissues, 
and ae a portion of the fibro-vascular bundl 
