488 Mr. E. Kidston on some Fossil Plants 



Cycadacea 



Cordaites, Unger. 



The internal organization of the leaves, flowers, and stems 

 of Cordaites have been fully described by Grand'Eury and 

 Renault*. According to Grand'Eury, the stems of Cordaites 

 attained a height of from 20 to over 30 feet, and were irregu- 

 larly ramified. At the upper extremities of the branches and 

 stems were borne the long narrow leaves. In Cordaites the 

 pith was chambered and the curious fossils, variously called 

 Sternbergia or Artisia, are casts of its pith-cavity. 



The wood in structure approaches closely to that of the 

 Coniferse, and was previously described as Pinites Brand- 

 lingii by Witham. It is also most probable that many of 

 the fossil woods referred to Pinites, Witham (Araucari- 

 oxylon, Kraus ; Araucarites 1 Goppert), are portions of the 

 stems of Cordaites. The wood-fibres bear one or many 

 vertical rows of bordered pits. The leaves are more or 

 less long in proportion to their width ; and from characters 

 derived from these organs, Grand'Eury proposes for Cordaites 

 the three following divisions : — 



I. Eucordaites. — Leaves spathulate, obovate, elliptical, or 

 lanceolate, sessile, entire, with rounded apices and of leathery 

 consistency. The leaves are from 20-90 centim. in length. 

 The nerves are either equally or unequally strong. 



II. Dorycordaites. — Leaves lanceolate with sharp points; 

 nerves numerous, fine, and equal in strength. The leaves 

 attain a length of from 40-50 centim. 



III. Poacordaites. — Leaves narrow, linear, entire, blunt at 

 the point, with nerves nearly equally strong. The leaves are 

 as much as 40 centim. in length t. 



The flowers of Cordaites are monoecious. The male flowers 

 consist of a number of imbricated bracts, in the axils of which 

 are situated the stamens, or they are placed around the de- 

 pressed apex of the axis of inflorescence. The female flower 

 contains several naked ovules, which are each short-stalked 

 and set in the axils of the bracts. Their fertilization takes 

 place in a somewhat similar manner to that of the Gycads 



• For a full description of the structure of Cordaites, see Renault, 'Cours 

 de botanique fossile/ premiere annee (Paris, 1881) ; Grand'Eury, " Flore 

 carbonifere du Departeruent de la Loire et du centre de la France " (1877) ; 

 Zittel-Schenk, ' llandbucb der Paliiontologie,' ii. Band, Lief. iii. p. 241 

 (1884). 



f Since writing the above a new type of Cordaites has been described 

 by Renault and Zeiller, which they have named Scvtocordaites (' Comptes 

 Rendus,' March 23, 1885). 



