482 Tansley and Lulham. — A Study of the 
Gleicheniaceous affinities of Matonia, recently expressed by Christ, who 
includes both in his class Oligangia, as well as by Bower, who places both 
families in his group of ‘ Simplices,’ and concludes that the affinities of 
Matonia are with Gleicheniaceae rather than with Cyatheaceae (’00, p. 45). 
The evidence for this view, which must be based primarily on the sporangial 
and soral characters, is difficult to impugn, and it seems to us to be 
strengthened by the morphology of the leaf, which appears to have much 
in common with the Gleicheniaceous type and nothing with the Cya- 
theaceous. 
Detailed Account of the Progressive Complication in the 
Vascular System of the Rhizome and Leaf-Trace 1 . 
(1) The six young Plants. 
A transverse section of the proximal end of Plant A (PL XXXI, Fig. 11) 
shows a very simple protostele, consisting of about twenty-four elements, 
surrounded by a pericycle and endodermis which are obviously sister-layers. 
The whole of the tissue of the stele apparently consists of xylem, which 
is made up of about ten scalariform tracheids and fourteen parenchyma- 
cells, exclusive of the pericycle. No phloem can be distinguished. The 
cortex is only three or four cells thick. 
This structure is maintained for a distance of about *5 mm., both cortex 
and stele increasing in diameter, but undergoing no alteration of struc- 
ture. The cortex then extends itself on the dorsal side of the rhizome 
preparatory to the origin of the first leaf 2 , while on each side, in connexion 
with the leaf base, a root is given off. The insertion of the steles of these 
roots on the stele of the stem takes place in front of (about -i mm. nearer 
the apex of the stem than) the insertion of the leaf-trace. 
The leaf-trace itself is of the simplest, consisting merely of a strand of 
tracheids, which are inserted almost perpendicularly on those of the stem- 
stele, surrounded by pericycle and endodermis, but, like the stele, apparently 
without phloem. The structure of such an early leaf-trace is in fact 
indistinguishable, except for its smaller size, from that of the stele of 
the rhizome. In neither is any trace of spiral elements to be seen. 
Immediately in front of the origin of the first leaf-trace and before the 
insertion of the two root-steles is reached, the stele of the rhizome is found 
1 It has been thought well to publish full details of the phenomena met with during the pro- 
gressive complication of the vascular system. A shorter and more general account, accompanied by 
explanatory tables and diagrams, will be found on pp. 496-502. 
2 It is of course possible that earlier leaves originally existed in this, the youngest specimen 
obtained. No definite indication of approach to the structure of the primary root was observed in 
the transverse section of the proximal extremity, .5 mm. below the first leaf ; but, on the other hand, 
the extreme simplicity of the structure of this part of the rhizome and of the leaf-trace indicates that 
the latter belongs at least to a very early leaf. 
