24 DESCRIPTIVE CATALOGUE 



long permanent bases of the petioles. Medulki entirely cellular, 

 with numerous gum-canals. Wood consisting of a thin inter- 

 rupted cylinder of striated tissue everywhere penetrated by 

 medullary rays. Fruits borne on secondary axis, not protruding 

 beyond the bases of the petioles." 



As Scott (1909, p. 560) points out, the elliptical stem-section 

 is not a true generic character, but otherwise, though incom- 

 plete, the diagnosis still stands. 



The most careful recent diagnosis is that of Lignier (1894, 

 p. 75) ; nevertheless, taking into account the importance of 

 the later discoveries, and in particular the notable work of 

 Wieland (1906), a revised diagnosis seems necessary. 



Diagnosis. Trunk shortly cylindrical or ovoid, externally 

 covered by persistent leaf-bases arranged in a close spiral, each 

 leaf-base roughly rhomboidal. Numerous ramenta between the 

 leaf-bases, which often persist in weathered specimens. Side 

 monostelic and hollow cylindrical. Pith cellular, with numerous 

 gum-canals ; wood composed of irregular primary groups of 

 elements, augmented by a secondary ring of radially arranged 

 trachcids much separated by wide medullary rays ; jJilocm 

 much developed. A single leaf-trace departs from the stele 

 and divides later. The leaf-bases contain a meristele irre- 

 gularly broken up into collateral bundles with variable amounts 

 of secondary thickening. Kumenta multicellular and fern- 

 like. Fructifications very numerous, borne laterally between 

 the leaf-bases which partly conceal them, Each fructifica- 

 tion consists of an axis with sterile scales and fertile ap- 

 pendages in considerable numbers, $ and <$ , generally, and 

 perhaps always, on the same cone. Kipe fruits consist of 

 scales and special stalks bearing orthotropous seeds, rf organs 

 having disappeared. Seeds contain each a large dicotyledonous 

 embryo within a differentiated testa. The two cotyledons of 

 the embryo practically fill the seed-cavity. 



Since Carruthers first (in 1870) described this interesting and 

 important genus much supplementary work has been done, the 

 more important of the papers dealing with it being Solins- 

 Laubach (1890, 1891), Capellini & Solms-Laubach (1892), 

 Lignier (1894 and others). Ward (1894 A & B), Seward (1895), 

 Scott (1909), Wieland (1006). and Berry (19 LI). Of these, 



