CORDAITEAE , 535 



thus be regarded as forms of transfusion - tissue. In 

 certain cases the hypodermal ribs are limited to the 

 upper and lower surfaces of the bundles, not occurring 

 between them. In one form (C. crassus) the leaf had a 

 distinctly fleshy character, as if adapted to xerophytic 

 life. Numerous stomata, of normal structure, occur in 

 these leaves, on the epidermis of the lower surface, to 

 which they seem to be limited. The general conclusion 

 to which we are led is that, while the leaf, in its simple 

 form and general structure, approaches most nearly to 

 that of such Conifers as Agathis, in the details of 

 internal organisation it agrees more closely with a single 

 leaflet of a Cycad, thus showing a striking combination 

 of characters, such as we have already met with in the 

 leaf of Poroxylon. 



5. The Flowers. — We now come to the most inter- 

 esting point in our present subject — the floral morpho- 

 logy of the Cordaiteae. The general arrangement and 

 external appearance of the inflorescences have already 

 been described. Our knowledge of these organs has 

 been built up by the labours of successive observers, 

 notably Carruthers, Grand'Eury, and Renault. It is to 

 the last-named author that our acquaintance with the 

 intimate structure of the flowers is chiefly due, for 

 M. Renault was so fortunate as to find silicified 

 specimens, allowing of minute structural investigation, 

 which were clearly of the same nature as the catkins 

 found on the branches of the Cordaiteae. As, how- 

 ever, the petrified flowers could, not be referred with 

 certainty to the particular members of the family 

 to which they belonged, the generic name Cordaianthus 



