.. dacea, the fronds are normally produced alternately, in a 
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66 ON GENERA AND SPECIES. 
less distance apart, and in an alternate manner on the sides ` 
of the progressing axis, the foot or base of attachment of 
the frond forming with the node a distinct and well marked ` 
articulation or joint, which ultimately becomes the point of ` 
separation of the mature frond, the node remaining per- ` 
manent in the form of a round more or less elevated ` 
eieacrix. This mode of growth includes all Polypodiacee, 
as restricted by me to the tribes Oleandre, Davallie, Poly- ` 
pode, and Platyceree. To this mode of growth I have ` 
given the name Hremobrya, and in characterising the genera 
the words vernation articulate are employed, and the pro- 
gressing axis from which the fronds are developed surculum. 
The number of species referable to Eremobrya, however, ` 
are few in comparison with those which possess a very — 
different mode of growth. If, for example, a plant of ` 
Lastrea Firmas be examined, the fronds will be found to ` 
be successively produced in a spiral manner from the apex 
of the stem, in the form of a corona or crown, and thus by 
successive development the stem is increased in height. ` 
All Ferns developing fronds in this manner, even the | 
smallest, the axis of which does not rise above the ground, te 
lofty tree Ferns, belong to this division as also a numerous ` 
class which produce fronds similar to the above, but which ` 
form a decumbent stem lying on the ground or but slightly - 
inclined upwards. This I term vernation fasciculate decum- 
bent, and the preceding vernation fasciculate erect. Another 
mode of growth is common to many Ferns, such for 
example in Pteris aquilina, Lastrea serra, Polybotrya osmun- 
single seriés, from the apex of a decumbent or creeping 
stem (sarmentum). In some cases this mode of growth 
resembles that of Eremobrya, but from which it is quite 
distinct, and is readily known by the vascular structure 
