2 Weiss, PJiloem of Lepidophloios and Lepidodendton. 



of the tissues very clearly, but are defective with regard to 

 a portion of the phloem. 



In Fig. 1 1 V){ Plate 49 it can be seen to consist of small- 

 celled parenchyma with "large isolated cells." Even in 

 the excellent preparations in the Hinney Collection of 

 Coal Measure Plants now at Cambridge, which have 

 recently been described by Seward (I.)' the phloem region 

 is only partially preserved. From an examination 

 of these preparations Seward concludes that the large 

 clear spaces which form so prominent a feature of Lepido- 

 phloios " cannot be satisfactorily explained as the result 

 of decay previous to mineralisation." He considers that their 

 appearance is suggestive of sacs or spaces formed, for the 

 most part during the life of the plant, by the separation 

 and partial disorganisation of thin-walled cells. " The 

 constant occurrence of patches of dark brown substance in 

 this zone " seems to him to point to a secretory nature of 

 the tissue, and hence he terms the phloem region the 

 secretory zone. This explanation is also advanced by 

 Seward (11.)^ for the appearance of similar large spaces in a 

 "Lepidodendroid stem from the calciferous sandstone of 

 Dalmeny, possibly identical with Lepidophloios Harcourtii 

 (Witham)." 



Among the specimens of Lepidophloios fuliginosits 

 in the Manchester Museum I have come across three 

 preparations, in the Cash Collection of Coal Measure 

 Plants, which throw a little further light upon the structure 

 of the phloem, by the excellent state of preservation of its 

 tissues. The three preparations (No. 409, 645 A, 645 B) 

 are all transverse sections cut from the same stem, 



> Seward, A. C. (I.). Proc. Cavth. Phil. Soc, Vol. X., Part III., 

 1900. 



•■^Seward, A. C. (II.). Tratis. Roy. Soi. Edinl:, Vol. XXXIX., 

 Part IX., No. 31, 1900. 



