[2587822] 
XVII. On Botrychioxylon paradoxum, sp. f a Paleozoie Fern with Secondary Wood. 
By D. H. Scorr, ERS., P.L.S. 
(Plates 37-41.) 
Read 18th April, 1912, 
In 1906, in a communication to the Royal Microscopical Society, I shortly described 
a new genus, named Botrychioxrylon, from the Lower Coal-measures of Lancashire, 
remarkable for possessing radially seriated wood, apparently of a secondary character 
(Scott, '061). Later in the same year I gave a somewhat fuller account of Botrychioxylon 
in an article in the * Progressus Rei Botanice’ (Scott, 062). I may quote this account 
as a brief introduction to the more detailed description of the plant to which the present 
paper is devoted :— 
“The branched rhizome is traversed by an almost cylindrical stele, the wood of which 
consists of two parts: the centre is occupied, as in Zygopteris, by small tracheides 
Scattered among parenchyma, while the main part of the wood forms a broad surrounding 
zone of much larger elements. The point of interest is that the outer zone has its 
elements radially arranged, constituting to all appearances a secondary tissue, just as is 
the case in Botrychiwm among recent Ferns. Otherwise the fossil bears considerable 
resemblance to Zygopteris corrugata: anatomically Botrychiorylon shows a relation to 
Zygopteris, like that of Botrychium to Ophioglossum, and it is on this ground that the 
name of the fossil genus has been selected.” I further pointed out in both com- 
munications that this was the only case as yet noticed among the Botryopterides * in 
which there was evidence of secondary growth. In the second edition of my ' Studies in 
Fossil Botany ' I again referred to the plant, suggesting that some real affinity with the 
Ophioglossaceze might be indicated (Scott, 08, pp. 318, 344). At that time I thought 
that Botrychiorylon might eventually have to be included under Zygopteris, but that 
genus has since been completely broken up by the researches of Dr. P. Bertrand. 
The relation of our plant to Ankyropteris corrugata (formerly Zygopteris corrugata) 
(Williamson, '77) will be discussed farther on in the paper (p. 384). 
The only other reference to Bofrychiozylon that need be mentioned here is one by 
Professor Bower (Bower, 7112, p. 546), whose short account of the structure 1s based on 
an inspection of the preparations in my collection. 
GENERAL STRUCTURE. 
species are based was found by Mr. James 
the horizon being that of the Upper Foot 
of sharpness in certain 
The specimen on which the new genus and 
Lomax in a coal-ball from Moorside, Oldham, 
Mine. The preservation is fairly good, though there is a want 
* Used in the wide sense, as by Renault, to include the Zygopteridese. 
SECOND SERIES.— BOTANY, VOL. VII. 
3K 
