380 
Miscellanea . 
opportunities of studying the stichidia than I possess, and to these 
organs he appears to attribute a higher place in classification than 
to the keramidia; for I find that he separates j Dasya from the 
neighbourhood of Polysiphonia , to associate it with Callitham- 
nion. This does not appear to me a natural arrangement while 
such a plant as Polysiphonia byssoidcs exists, which presents the 
stem and fruit of a Polysiphonia , with the single tubed, byssoid 
ramuli of Dasya. 
As the frond of Claudea is proliferous, its divisions, as its 
growth extends, are but a repetition of the first formed frond, the 
whole consisting of a congeries of falcate, unilateral, seemingly 
skeleton leaves, every new leaf springing from the back of the 
midrib of the older leaf. By explaining therefore the formation 
of a single leaf, we shall learn that of the whole frond. If we 
take a full grown leaf for the purpose of examination, we can 
learn but little from it, the processes of metamorphose having 
been completed, and we shall be liable to fall into erroneous con¬ 
jectures on the subject. But by taking off a young leaf which is 
not yet unrolled from its circinate vernation, and is still but an 
eighth of an inch in length, the manner of growth in this remark¬ 
able plant may be very clearly seen. At this age the future leaf 
is found to consist of a lanceolate lamina, furnished with a strong 
midrib, acute, and resembling the leaf of Delesseria hypoylossum 
in form, rolled inwards at the apex, in a circinate manner; its 
midrib producing at right angles with the lamina, and on the 
surface towards which the apex rolls, a series of processes or leaf¬ 
lets (the nervures of the future leaf) of similar form and structure 
to the leaf from whose midrib they spring, set at equal distances 
to each other, and continuing from a short way above the base of 
the leaf to its apex. As these leaflets increase in size, the lowest 
in the series emits from its midrib along the upper face, a similar 
series of processes, which, springing from it upwards and lengthen¬ 
ing, meet with the back of the leaflet placed next in order above, 
and parallel with it, and become united to it, forming a series of 
bars; and this process goes on until all the leaflets are linked to¬ 
gether. Finally a similar connection by processes occurs among 
the bars, and the net work of the leaf is then ready to unroll and 
