the stipes being adherent, indicates their position to be 
68 : ON GENERA AND SPECIES, 
the division Eremobrya generally arrive in good con- 
dition, while those of Desmobrya, especially such as have ` 
slender stems, are often dead or in a very enfeebled state — 
on their arrival. 
The difference in the structure and mode ot growth of ` 
the species of these two divisions may be admitted to be of ` 
equal importance for classification with the difference in ` 
structure of Exogens and Endogens in flowering plants. 
In all attempts to determine natural relationship on any ` 
special organ or structure, exceptions are never wanting. 
In the present case, examples of connecting links are in a 
few instances found between the two divisions. This is ` 
particularly so with the genus Elaphoglossum, which con- — 
sists of numerous simple-fronded Ferns, and may be 
viewed as a truly natural genus. In many of the species 
the stipes have an evident articulation situated in some, 
more than half an inch above its base, and in many 
of the species it is marked by a slight swelling ; and 
also by the part below the swelling being of a dark colour. 
. No change, however, takes place in the structure, the bun- 
dies of vascular fibre pass uninterruptedly through the 
apparent articulation, but they are evidently weaker at 
that point; for, when mature, the stipes separate there, 
the base portion remaining attached to the developing axis, 
which is either fasciculate or uniserial and adherent. I 
. therefore place Elaphoglossum in Desmobrya. ; 
- Another instance of the stipes being jointed above its 
_ base is characteristic of the original species of the genus 
- Woodsia, as also in species of Arthropteris; but the base o 
in Desmobrya. Also special examples of the articulation 
of the stipes in fasciculate vernation is exhibited by the 
genus Trichopteris and several species of Cyathea; ` 
