PROCEEDINGS OF SOCIETIES, 283 



tion th<it tills arose from the fusion of two bundles back to back. He 

 li.id himself ascertained the occurrence of extremely large scalariform 

 ducts in SiiiUax. It was evident that geologists should be careful in de- 

 termining plants from the nature of the vessels. Professor Wyville 



Thomson said that the chain-like crystal-bearing tissue would, if it proved 

 characteristic oF Screw-pines, be a valuable menus of determining {\w, na- 

 ture of some fossil monocotyledoiious stems. Neil Stewart, " Observa- 

 tions on the Intimate Structure of Spiral Ducts in Plants, and their 

 Kelationship to the Flower." It is to be regretted that this pap;^r was 

 permitted to be read. It exhibited a fundamental misconception of the 

 most elementary points in vegetable minute anatomy. A considerable 

 portion of the paper was devoted to the description of "a vascular 

 system" within the epidermal cells of a Hose-petal, "rivalling in com- 

 plexity the structure of the human eye." [A reference to Carpenter's 

 ' The Microscope,' 4th edition, p. 425, will show what the author really 

 attempted to describe.] 



Augimt 8. — Professor Balfour, " On the Cultivation of Tpccacuanlia in 

 tlie Edinburgh Botanic Garden for transmission to India." Besides the 

 plant which had long been in the garden, what was apparently another 

 species had been received from Dr. Gunning. It resembles more than 

 the garden plant the figure of Martins. The leaves were more pointed 



and less leathery. Professor W. C. Williamson, " On the Classification 



of the Vascular Cryptogamia, as affected by recent Discoveries among the 

 Fossil Phints of the Coal-measures." The author thought that justice 

 had never been done to Professor King, of Galvvay. He did not say that 

 his paper (' Edinburgh New Philosophical Journal,' 1844) was accurate 

 either in details or in its broad features, but thought, nevertheless, that 

 the value of the communication had never been recognized. He wished 

 to insist on the exogenous growth of the woody axis belonging to stems 

 of the Carboniferous Cryptogams. In Calamites, which, though not ex- 

 actly Ecpiisetaceae, were tiieir representatives, the central pitli was sur- 

 rounded by a cylinder of wedges resembling those of young Dicotyledons. 

 These wedges sometimes not less than two inches in thickness, and wholly 

 vascular, were a clear proof of exogenous growth. Amongst Lycopodia- 

 ceous plants, Adolphe Brongniart distingnished Lepidodendroid and 

 Sigillarian plants. In Sigillaria there were two distinct zones, but in 

 Lepidudendron there was no such arrangement ; these he I'egarded as Ly- 

 copodiacea, but Sigillnrins as gyninosperms. However, he (Professor 

 Williamson) was in a position to show that in Lepidodeiidron there is a 

 representative of the second ring. Lepidodendron, according to his view, 

 lias a vascular pith, surrounded by a true woody zone, from which bundles 

 are given oif. The specimen had been carefully figured by Carrnthers, 

 though he differed from him in details, especially in asserting the existence 

 of medullary ra\ s. There was a very elaborate cortex, very corky in some 

 plants, very fibrous in otiiers. The Sujillarin vascularis, of Binney, in- 

 cludes two forms, one in which tlie medulla is dilfercntiated into medul- 

 lary cells, and peripheral vessels ('medullary zone'), and the woody zone 

 exhibits mechillary rays. Tlie Dlploxj/Jon of Corda, has proved tiiat' ravs 

 do not proceed from the medulla, but from the woody zone. In Stigmaria 

 he also maintained that the vascular bundles proceeding from rootlets are 

 derived from tlie cylinder and not from the medulla. In these plaids, as an 

 evolutionist, he looked upon the ' medullary zone' as corresponding to the 



