Manchester Memoirs, Vol. xlv. (1901), No. 7. 



VII. On the Phloem of Lepidophloios and Lepido- 

 dendron. 



By Professor F. E. Weiss, B.Sc, F.L.S. 



Received aitd read October 30th, igoo. 



The structure of the phloem in the genus Lepidophloios 

 and in the nearly allied genus Lepidodendron has been 

 the subject of much discussion and of considerable differ- 

 ence of opinion. This is mainly due to the fact that its 

 delicate tissues are rarely found in a good state of pre- 

 servation. For, while the dead and Hgnified elements of 

 the wood are not liable to much injury, the phloem, 

 composed as it is, in all plants, largely of delicate living 

 cells, is much more subject to speedy decay on the death 

 of the plant, and is therefore less commonly met with in 

 the fossil condition in a good state of preservation. In 

 the two genera referred to above it is often not preserved 

 at all. 



Examining, as I have done, a very large number of 

 specimens of LepidopJdoios and of Lepidodendron in the 

 Cash, Hick, and Wild Collections of Coal Measure fossils 

 in the Manchester Museum, I have found only a very few 

 specimens in which the tissues of the phloem region were 

 moderately well preserved, even when such delicate cells 

 as those of the mid-cortex and of the cambium were fairly 

 perfect. 



The sections of LepidopJdoios fidiginosus figured by 



Williamson under the name of Lepidodendron Harcourtii 



in his Xlth Memoir on the Organisation of the Fossil 



Plants of the Coal-Measures^ show the details of most 



1 Williamson W. C, Phil. Trans., Part II., 1881. 



July lotli, igoi. 



