354 ON THE STRUCTURE OF THE FRUIT OF CALAMITES. 
and to which species Brongniart confines the name Hippurites ; and 
lastly, a genus (Phyllotheca) of Oolitic plants from Australia, described 
by M'Coy, but which seems to me to have no affinity with the other 
genera of his family. He excludes Calamities, placing it in Eqidsetacea . 
I have in a former paper (Journ. of Bot. Vol. IV. p. 345) described the 
structure which I observed in some stems of Catamites, and which differs 
somewhat from anything before described; further light may be expected 
to be thrown on this subject when Mr. Binney publishes his observa- 
tions on and illustrations of this tribe of fossils, on which he has been 
engaged for many years, and which I had hoped to have seen long 
ago. I have no doubt that a considerable diversity exists in the struc- 
ture of the steins of these plants, but I am satisfied from numerous 
observations that no true medullary rays occur, — or rather that the 
larger or smaller wedges of cellular tissue which alternate with the vas- 
cular bundles cannot be considered true medullary rays. I hope, 
however, to examine this subject at greater length, and under more 
satisfactory circumstances, when I have investigated a collection of re- 
markably preserved stems and branches of coal plants which I obtained 
last autumn from the beds of trappean ash in Aiian, where they were 
first detected by my friend E. A. Wiinsch, Esq., and who has placed a 
large series of his own specimens at my service. With these materials, 
and with the results of Mr. Binney's labours before me, I shall be 
more able to deal with this subject. 
Three forms of foliage (excluding Hippurites, founded on a single 
very fragmentary specimen) have been referred by Brongniart to As- 
terophyllitea, but of these he considers Aster nphyllites alone to be the 
foliage of Calamodendron. Sphenophylliim and Anmdaria he supposes 
to have been water-plants, and but for the similar structure of the fruit 
of the first genus, and the similar arrangement of the foliage in both 
to Aster ophyllites , he seems inclined to consider these two genera to 
be Cryptogams. M. Coemans, who has recently monographed the two 
genera, takes the same view of their habit and systematic position. 
The evidence of the affinity of Aumdaria was not so complete m 
Brongniart's estimation as that of Sphenophyllum. Germar has, how- 
ever, described and figured a fruit belonging to this form, and it agrees 
entirely with those of the other two forms. And that Annular ia was not 
a slender floating plant is proved by a specimen in the collection of the 
British Museum, in which three leaf-bearing branches spring from the 
nodes of a thick calamitoid branch, about half au inch across. 
