486 Carruthers — On Caulopteris punctata, — 
presentatives. The specimens occur in a thin coal-seam, which is 
covered by a red sandstone rock, and rests on a bed of grayish blue 
clay, in which are found the remains of plants peculiar to the Chalk. 
The beds at Kaunitz are then of the same age as those at Shaftes- 
bury, and there can be no doubt that the fossil is the same species. 
The only means of determining the affinities of this fern are to 
be obtained from the leaf-scars. Both Brongniart and Goeppert 
have shown that these are of considerable systematic value. The 
figures in the scars are produced by the vascular bundles ; and as 
these are related to the form of the frond, and even to the spore- 
bearing nerve, it is evident that allied plants will agree more or less 
in the arrangement of the vascular bundles. This subject has not 
yet received the attention in tree-ferns that it deserves. The 
arrangement of the bundles in the stemless species found in Europe 
has been described by Douval-Jouve, Ogilvie, Church, .&c. ; and 
their importance has been shown in their giving additional dis- 
tinguishing. characters to allied species, and in uniting others 
that had been separated on insufficient data. The peculiarities I 
have described in the leaf-scars of Caulopteris punctata, are remark- 
ably like what we find in the recent genus Dicksonia. There is 
placed on the plate a drawing of a portion of the stem of Dicksonia 
antarctica for comparison (Fig. c.). Were the scars sufficient to 
determine the species I would not hesitate to place it in this genus, 
but all the parts employed by botanists in the classification of ferns 
are wanting. In the manuscript name which I had given to it, I 
expressed as much regarding its affinities as the materials enable 
me—it is a Dicksonia-like fern-stem. Not only in the structure of 
the scar, but also in its small size, and in the consequent small frond, 
it is nearer to Dicksonia than to Cyathea. 
The specimen exhibits five very slight constrictions produced by 
seasonal interruptions to the growth, three of which are shown in 
the plate. In the fern-stems from tropical and sub-tropical regions 
which I have examined, I can find no evidence of such interruptions 
in the growth. I have, however, observed similar constrictions in 
stems of native ferns grown under favourable circumstances in 
Britain. Some-years ago I obtained, in a gully on the side of Ben 
Lomond, specimens of Lastrea Filix-mas with true stems a foot in 
length, which showed that they were then in their fourth year by 
the three constrictions on the stems ; and specimens of Polystichum 
Lonchitis which I have seen in the herbarium of N. B. Ward, Esq. 
collected on the west coast of Ireland, exhibit numerous similar 
annual constrictions in a very beautiful manner. This appearance, 
then, on the stem from Shaftesbury seems to indicate an alternation 
of climate similar to what we now experience in Britain, and this is 
further attested by the exogenous rings in the specimens of fossil 
wood to which I have alluded. These rings are of different thick- 
nesses, one season having been then more favourable to the growth 
of the plant than another, as at the present day. It is well to 
remember here, however, that cold is not the only physical cause of 
interruption, but that a periodic dry wind as on the coast of China, 
