1884.] Leaf of Vascular Cryptogams and Gymnosperms. 61 



carbonic oxide. The excess of inert oxygen has the same effect as 

 the inert nitrogen in favouring the formation of carbonic acid. 



The variations in the coefficient of affinity found by Horstmann 

 with different quantities of oxygen are due partly to this cause, but 

 chiefly to the varying amounts of steam condensed by the cold 

 eudiometer during the reaction in different experiments. 



As the general result of these experiments it has been shown that 

 when a mixture of carbonic oxide and hydrogen is exploded with 

 insufficient oxygen for complete combustion, at a temperature at 

 which no condensation of steam can take place during the reaction, 

 and at a pressure greater than the critical pressure, an equilibrium 

 between two opposite changes is established, which is independent of 

 the quantity of oxygen taken, so long as this quantity is less than 

 half the hydrogen. Within the limits marked out above, the law of 

 mass is completely verified for the gaseous system composed of 

 carbonic oxide, carbonic acid, hydrogen, and steam at a high tem- 

 perature. 



II. "On the Comparative Morphology of the Leaf in the 

 Vascular Cryptogams and Gymnosperms." By F. 0. BOWER. 

 M.A., F.L.S. Communicated by W. T. THISELTON DYER, 

 M.A., F.L.S. Received May 13, 1884. 



(Abstract.) 



Eichler, in his dissertation on the development of the leaf, defined 

 the primordial leaf as the young leaf before internal differentiation or 

 external distinction of parts ; and further pointed out that subse- 

 quently two parts of it may be distinguished the foliar base (blatt- 

 grund) which gives rise to the sheath and the stipules, if present, and 

 the upper leaf (oberblatt) which developes into the simple branched 

 lamina. The petiole is also, according to Eichler, derived from the 

 upper leaf, though Goebel describes it as being intercalated between 

 the two parts. The first part of the present paper is devoted to a 

 discussion of this mode of treatment of the leaf. In accordance with 

 the views clearly expressed by Sachs and others, the terms stem and 

 leaf are to be regarded only as expressions denoting certain relation- 

 ships of the parts of the shoot ; the leaf is essentially an outgrowth 

 from the stem. If this proposition be accepted, the same mode of 

 morphological treatment ought to be applied to both. Now, in the 

 treatment of the shoot as a whole, priority of importance is always 

 attached to the mode of origin, and sequence of appearance of the 

 several parts, while subsequent changes of conformation and dis- 



