OF THE FOSSIL PLANTS OF THE COAL-MEASTJKES. 
693 
These latter sections (figs. 35 F, G, H, I, & K) do much to clear up the obscurities of 
this interesting stem. We now learn that there were certaiftly three sets of branches 
given off from the primary petiole, viz. the secondary ones with the large crescentic 
section ( aa ) of the above figures, the ternary ones (otf) of the same series, and the 
quaternary ones (x" 1 ). Those represented by the letter x' were obviously given off from 
the barred portions of the crescentic bundles (aa) in the manner usually seen amongst 
such recent ferns as possess a similar bundle, viz. alternately from each of the two horns 
of the crescent. These may have been the ultimate rachis sustaining the leaflets, one 
of which (fig. 35 I, x'") may have been merely a small petiole of a leaflet ; but even if 
the latter represents a yet more peripheral or quaternary series of subdivisions, I think 
I have now proved the existence of that simple alternate arrangement in the orientation 
of the ultimate bundles, the want of which was so perplexing in the larger petioles. 
Since I have in no solitary instance met with a petiole containing two crescentic 
bundles, it is clear that those (aa, aa) of fig. 35 E went to two distinct subdivisions of 
the primary petiole. Hence it seems to become an indisputable conclusion that, what- 
ever this arrangement may signify, these secondary rachides were given off in pairs, 
springing alternately from opposite sides of the primary petiole, but that they in their 
turn bore other subdivisions, which were arranged in the usual alternating and 
distichous order — these distichous branches themselves either having directly borne 
the leaflets, or if not having given rise to other and yet smaller distichously arranged 
subdivisions, upon which the leaflets were planted. It is scarcely necessary to say that 
this arrangement is an anomalous one. I know of no recent fern in which the secon- 
dary branches of the petiole are thus given off in pairs, which pairs are distichously 
arranged on the primary axis, and each of which secondary petioles sustain ternary ones 
arranged distichously. Not only will a somewhat similar case come before us on a later 
page of this Memoir in Corda’s genus Zygopteris , but the structure of the RacMopteris 
Oldhamia just described suggests the possibility that a somewhat similar arrangement 
may have existed in its case. The full meaning of these peculiar relations of the 
secondary branches to the primary petioles can only be cleared up by further research. 
The plant represented in fig. 28 has not yet been discovered in the Lancashire district; 
but Plate LV. fig. 41 and Plate LVI. fig. 41 A represent two transverse sections of 
petioles, also with reticulated vessels, and which obviously bear some considerable 
resemblance to Plate LVI. fig. 39. Mr. Carruthers has favoured me with the sight of 
a similar section to fig. 41, from the Newcastle coal-field, and for which he was indebted 
to Professor King, of Galway. 
The next plant to be described belongs to a type that has already been figured and 
described by previous observers. Cotta figured a stem from Chemnitz (Dendrolithen, 
tab. i. fig. 1) which he designated Tubicaulis primarius , and which he regarded as 
identical with the Endogenites solenites of Sprengel. The petioles attached to this 
stem were numerous, and each one had in its centre a vascular bundle, the transverse 
section of which somewhat resembled the letter H. Corda subsequently made this 
5 a 2 
