484 REPORT—1883. 
Stigmaria. The statement rests upon an entire misinterpretation of sections of the 
fibro-vascular bundles supplying those rootlets and an ignorance of the nature and 
positions of the rootletst, hemselves. More than forty years have elapsed since 
John Eddowes Bowman first demonstrated that the Stegmarie were true roots, and 
every subsequent British student has confirmed Bowman’s accurate determination. 
M. Lesquereux informs me that his American experiences have convinced him 
that Siyillaria is Lycopodiaceous. Dr. Dawson has now progressed so far in the 
same direction as to believe that there exists a series of Sigillarian forms, which 
link the Lepidodendra on the one hand with the Gymnospermous exogens on the 
other. As an evolutionist I am prepared to accept the possibility that such links 
may exist. They certainly do, so far as the union of Lepedodendron with Sigillaria 
is concerned. I have not yet seen any from the higher part of this chain that are 
absolutely satisfactory to me, but Dr. Dawson thinks that he has found such. I 
may add that Schimper, and the younger German school, have always associated 
Sigillaria with the Lycopodiacee. But there are yet other points under discussion 
connected with these fossil Lycopods. 
M. Renault affirms that some forms of Halonia are subterranean rhizomes, and 
the late Mr. Binney believed that Halonie were the roots of Lepidodendron. I 
am not acquainted with a solitary fact justifying either of these suppositions, 
and unhesitatingly reject them. We have the clearest evidence that some Halonie 
at least are true terminal, and, as I believe, strobilus-bearing, branches of 
various Lepidodendroid plants; and I see no reason whatever for separating 
Halonia regularis from those whose fruit-bearing character is absolutely deter- 
mined. Its branches, like the others, are covered throughout their entire 
circumference, and in the most regularly symmetrical manner, with leaf-scars, a 
feature wholly incompatible with the idea of the plant being either a root or a 
rhizome. M. Renault has been partly led astray in this matter by misinterpreting 
a figure of a specimen published by the late Mr. Binney. That specimen being 
now in the museum of Owens College, we are able to demonstrate that it has 
none of the features which M. Renault assigns to it. 
The large round or oval, distichously-arranged, scars of Ulodendron have long 
stimulated discussion as to their nature. This, too, is now a well-understood 
matter, Lindley and Hutton long ago suggested that they were scars whence cones 
had been detached ; a conclusion which was subsequently sustained by Dr. Dawson 
and Schimper, and which structural evidence led me also to support.! The 
matter was set at rest by Mr. d’Arcy Thompson’s discovery of specimens with the 
strobili zn situ. Only a small central part of the conspicuous cicatrix character- 
ising the genus represented the area of organic union of the cone to the stem. 
The greater part of that cicatrix has been covered with foliage, which, owing to 
the shortness of the cone-bearing branch, was compressed by the base of the cone. 
The large size of many of these biserial cicatrices on old stems, has been due to the 
considerable growth of the stem subsequently to the fall of the cone. 
Our knowledge of the terminal branches of the large-ribbed Sigillarie is still 
very imperfect. Paleeontologists who have urged the separation of the Siyillarie 
from the Lepidodendra have attached weight to the difference between the 
longitudinally-ridged and furrowed external bark of the former plants, along which 
ridges the leaf-scars are disposed in vertical lines, and the diagonally-arranged 
scars of Lepidodendron. They have also dwelt upon the alleged absence of ~ 
branches from the Sigillarian stems. I think that their mistake, so far as the 
branching is concerned, has arisen from their expectation that the branches must 
necessarily have had the vertically-grooved appearance and the longitudinal 
arrangement of the leaf-scars, observed in the more aged trunks; hence they 
have probably seen the branches of Styil/arie without recognising them. _ I believe 
this to have been the case. I further entertain the belief that the transition from 
the vertical phyllotaxis, or leaf-arrangement, of the Sigillarian leaf-scars, to the 
diagonal one of the Lepidodendra, will ultimately be found to be effected through 
the sub-genus Favularia, in many forms of which this diagonal arrangement be- 
1 Memoir ii. p. 222. 
