44 HICK : SOME RECENT ADVANCES IN BRITISH PALiEOBOTANY. 
Since then M. Renault 1ms published the results of further 
investigations on the subject," which fully establish the correctness 
of his views, so far as they affect the French fossils which he refers to 
the genus Ast7'omyelon. 
This led to a re-investigation of the English specimens of 
Astromyelon by the late Prof. Williamson and Dr. D. H. Scott, who 
communicated a memoir to the Royal Society in October of last year, 
specially devoted to the roots of Calamites. At the time of writing, 
the memoir has not been published in extenso with the usual illustra- 
tions, but an abstract of it will be found in the Proceedings .t In 
this the authors express the opinion that Renault's views of the 
nature of Astromyelon may be safely extended to our English fossils. 
They found specimens of Astromyelon arising as adventitious roots 
from the stem of Calamites, and having all the characteristics of 
normal roots, including centripetally developed primary xylem 
strands, alternating in the primary stage with phloem strands, and at 
a later period with the secondary xylem bundles. 
It seems then that the evidence asked for in 1891 as to the 
root-nature of Astromyelon is now supplied, and that the blank in 
our knowledge of the structure of the roots of Calamites has been 
satisfactorily filled up. 
In saying this, however, it must be added that, so far, my own 
observations have not confirmed this view of the nature of Astromyelon. 
I have carefully examined a large number of preparations of the 
fossil, some of them in a state of preservation which is practically 
perfect, so far as the critical tissues are concerned, and have failed 
to distinguish the centripetally developed primary xylem strands, 
from the secondary xylem bundles. Under these circumstances it 
will be for further investigation to show whether two distinct plants, 
or parts of plants, have hitherto been confused under the name of 
Astromyel n, or whether there is some other explanation of the 
apparent discrepancy. 
The Stem. — In 1891, the structure of the aerial stems of Calamites 
was said to be tolerably well known, at least in a general way, but it 
* Flore fi-. slle J'Autun, etc., pt. ii., 189.S. 
t Proceeding.^: of the Royal Society, vol. Ivii., 1894. 
