3o6 Recent Literatui-e. [zoe 



carboniferous formation, that they possess reservoirs of tannin or 

 various mucilaginous matters, besides resiniferous ducts in great 

 abundance. This is the case for instance in Sigillaria, the 

 bark of which shows numerous secreting ducts; in the petioles of 

 Myelopteris which are almost perforated by gum-ducts; in the 

 leaves and branches of the Dolorophylleae, where each mestome- 

 bundle is accompanied by numerous ducts; and in the outer- 

 most layers of the bark in Colpoxylon, Medullosa and 

 Cycadoxylon which show the presence of a very large number 

 of gum-reservoirs. Such examples might easily be multiplied 

 A very interesting addition to this flora of the permo-carboniferous 

 formation is the new genus Retinodendron, which the author 

 describes in the present paper. 



The material, upon which the genus has been established, 

 was collected near Autun, in France, by Mr. Rigollot. It con- 

 sisted of a stem, of which only the inner part was preserved; the 

 bark was, unfortunately, wanting. The author succeeded, how- 

 ever, in identifying the family to which this stem belonged, and 

 he has referred it to the Gymnospermae on account of the struc- 

 ture of the hadrome. 



The leptome showed the singular fact, that certain parts were 

 composed of several concentrical zones of gum-ducts and sclerotic 

 cells in regular alternation with each other. The content of 

 these gum or probably resin ducts was a brown and somewhat 

 granular substance. The ducts themselves were surrounded 

 rounded by a sheath of thin-walled cells, around which another 

 sheath was formed of similar cells, the walls of which showed 

 some kind of irregular perforation. This first zone of gum-ducts 

 included about fifteen concentrical rows, but outside this was a 

 second zone, consisting of twenty-four rows of similar ducts; 

 thereupon followed a circle of sclerotic cells, after which again a 

 third zone of more than fift}- concentrical layers of the same 

 gum-ducts, as described above. 



This very regular arrangement of the ducts and sclerotic cells 

 reminds one of the Poroxylece; but in the latter it is the sieve- 

 tubes and parenchymatic cells, which show this regular 

 arrangement. 



