The London Botanical Society . 4 ! 
he given. The substance of papers read will not be reported without 
the express consent of the readers. 
The first meeting in 1903 was held on Tuesday, January 20th, 
at 4.30 p.m., Dr. D. H. Scott in the Chair. Mr. A. G. Tansley gave 
an account of the “Vascular System of Matonia pectinata and its 
relation to those of other Ferns.” The account embodied the 
results of work, mainly carried out by Miss R. B. Lulham at 
University College, on material collected by Mr. Tansley on Mount 
Ophir in Johore, Malay Peninsula (the classical locality for the 
comparatively rare fern M. pectinata ), in January, 1901. Reference 
having been made to Mr. Seward’s original description of the 
anatomy of the rhizome and petiole (Phil. Trans., 1899) and Miss 
Wigglesworth’s discovery that the rhizome may contain three 
concentric “amphiphloic siphonosteles” (New Phytologist, July, 
1902), it was shewn that all transitional cases may occur in the 
rhizome of the mature plant between a vascular system composed 
of two and one composed of three concentric siphonosteles. From 
a preliminary investigation of the young plants, it appears that the 
first formed portion of the stem contains a single solid “protostele,” 
which becomes medullated at a higher level. From the interior of 
this a second protostelic strand is nipped off, and this, coming into 
connexion with the primary stele at the nodes, gradually passes 
throqgh the “ Lindsaya- phase” into the siphonostelic condition. 
The two concentric siphonosteles thus obtained may exist alone in 
the mature rhizome, hut frequently a third strand is nipped off from 
the interior of the second, or arises freely in the pith. This may 
remain protostelic, it may pass into the “ Lindsay a- phase,” or it may 
itself become siphonostelic. 
The rest of the account was devoted to a consideration of the 
nodes, of which 35 had been examined. The typical structure was 
made clear by means of drawings of a solid model of the vascular 
system, and the exact relations of the three steles to the leaf-trace 
elucidated. A theory of the gradual evolution of this from the 
simple curved leaf-trace characteristic of ferns possessing a single 
siphonostele in the stem, in connexion with the evolution of the two 
inner steles and in accordance with the transitional structures found 
in the young stem, was put forward, and its probable physiological 
causes outlined. Finally a fundamental similarity was suggested 
between the course of evolution in Matonia and the other ferns 
having a “polycyclic” arrangement of vascular strands in their 
stems, e.g. Saccolonia, Cyatheaceae, Marattiaceae, etc., the general 
view being that the additional internal strands are always primarily 
“compensation-strands” (Ersatzstrange). Mr. L. A. Boodle, 
Mr. C. E. Jones and Dr. Scott took part in the discussion. 
