1 5 
Mesoxylon and an Allied Genus. 
morphological nature, differing from vegetative branches. They might 
then belong to some species of Mesoxylon. But specimens of ordinary 
vegetative stems of the Mesoxylon type have now come to light which 
agree with these shoots in having single leaf-traces, and it is suggested that 
the shoots belonged to a plant of this kind. The stems in question will be 
described immediately; in the meantime the attribution of the bud-like 
shoots must be left an open question (see p. 17). 
There is nothing to show that these shoots were connected with 
reproduction ; they have all the character of vegetative buds, and bear no 
resemblance to any form of Cor daian thus. If they bore branches of the 
nature of fructifications, no trace of any such organs is to be found in 
the specimens. Yet the association with Mitrospermum seeds, and espe- 
cially with young seeds, is striking. Probably it is accidental, for if all 
the seeds are of the same species they could not have been borne both 
on these shoots and on the Cordaianthus of Mesoxylon multirame. 
I shall return to the subject of association at the conclusion of 
the paper. 
Stems of the Mesoxylon Type with a Single Leaf-trace — 
r a New Genus. 
The stems in question are represented only by two isolated transverse 
sections in my collection. 1 The smaller of the two specimens (2983) is 
about 11 mm. in diameter in its present condition, but the cortex is incom- 
plete (PI. II, Fig. 11), The stele (to the outer edge of the wood) measures 
about 9x8 mm. and the pith about 5 x 3*5 mm. The pith is almost 
destroyed by Stigmarian rootlets, and it is impossible to determine whether 
it was discoid or not. The small-celled wood is from 1-3 to 2*5 mm. thick. 
The medullary rays are narrow and uniseriate, and the general structure of 
the wood, so far as can be judged from a transverse section, is similar to that 
of a Mesoxylon , such as M. multirame or M. poroxyloides. It also agrees 
essentially with that of the bud-like shoots described in the preceding 
paragraphs. 
Three leaf-traces, each manifestly a single bundle, are seen on their 
course through the wood ; they pass out obliquely but not horizontally. 
In two of them the centripetal xylem can be clearly seen, and in one, at 
any rate, the intermediate position of the protoxylem is evident (PI. II, 
Fig. 12). A fourth bundle is just leaving the pith, and this also sltbws the 
same mesarch structure. The inner edge of the wood is not well preserved, 
and though there are indications of centripetal wood at some points, it 
is nowhere very clear, apart from the outgoing traces. The phloem and 
1 The numbers are 2983 and 2993, both received from Mr. Lomax early in 1916; they were 
found at Shore, Littleborough. 
