OF THE CATAMITES OF THE COAL-MEASURES. 
503 
but it seems to me undesirable to do so ; though there are some points of resemblance 
between the two plants that sorely tempt a botanist to do so. But before attempting 
to determine the question, we must ascertain what are the several points of resemblance 
and of difference. 
Different botanists have defined the Equisetacete in various ways ; but most of these 
definitions of the family include two things: 1st, a sheath to each joint of the stem; 
and 2nd, hygrometric elaters attached to each spore. That the former of these has no 
existence in Calamites is universally admitted*. The plant figured in M. Brongnxart’s 
great work under the name of Calamites radiatusf , exhibits what that distinguished 
botanist regarded as a true sheath. But I recently examined the specimen which is, or 
was, in the Strasburg Museum, and I satisfied myself that the supposed sheath is a mere 
verticil of leaves ; a conclusion in which its eminent custodian, Professor Schimper, fully 
agreed with me. Consequently the fact must be admitted, that one of the universally 
existent features of recent Equisetaceous plants does not appear in the fossil Calamites. 
In his description of his VolJemannia Binneyii Mr. Carruthers announces the dis- 
covery of spores with attached elaters, and on the strength of this supposed fact he 
further rests his conclusion that the Calamites are Equisetacese. But to this I enter- 
tain two objections. I have not seen Mr. Carruthers’s specimen, but I have made sec- 
tions of and examined a considerable number of strobili of the same species ; and though 
I find spores in abundance, I have failed to detect a solitary example furnished with ela- 
ters. I think the evidence for a conclusion, so scientifically important as that to which 
the recognition of elaters would lead us, must be very clear and decisive before we ac- 
cept it ; and if we find one solitary example which may possibly be interpreted as bearing 
such organs and a large number of others, of the same species, in which no such organs 
can be found, we must be quite sure that the exceptional specimen is incapable of any 
interpretation that will bring it into harmony with all others of the same sort. Judging 
from his figures, I think it probable that, in Mr. Carruthers’s specimen, the outer cell- 
walls of the spores have become accidentally ruptured, and the detached portions pro- 
jecting from the spores have been mistaken for elaters. But even if, contrary to expec- 
tation, elaters should be shown to exist in these cones of Yolkmannise, it still remains to 
be proven that the species in question belongs to Calamites ; and until such connexion 
is established we must scarcely, on the strength of its possibility, alter our definition 
of a great and important natural family of plants. 
I am not aware that the minute organization of the Equisetums has yet been illus- 
trated in detail by any English writer ; but it has been very effectively done by the late 
Dr. J. Milde in his ‘Monographia Equisetorum’J. But even this admirable mono- 
* If we regard the sheaths of Equisetums as verticils of coalesced leaves, the verticils of free leaflets supposed 
to exist iu Calamites may he said to represent them. In the former case these verticils exist persistently on 
the deep subterranean rhizomes, as well as attached to the aerial stems. Nothing takes the place of these sub- 
terranean appendages in Calamites. 
f Yegetaux Fossiles, tab. 26, figs. 1, 2. 
i. Nov. Act. Academiae Caesariae Leopoldino-Carolinse Germanicae Naturae Curiosorum, Dresden, 1867. 
3 z 2 
