Manchester Memoirs, Vol. xlv. (1901J, No. 7. 15 



from the sieve tubes and storing for the use of the cambium 

 or of the developing wood cells, the food material which 

 passes down the sieve tubes. Frank^ and Blass^ indeed 

 consider the function of the phloem as a whole is more 

 nutritive than conducting, but at any rate we should 

 expect to find in the leaf trace bundles the conducting 

 function outweighing the storage or nutritive function. 



The difference in the aspect of the phloem in the 

 figures of Binney and Seward as compared with those 

 given in this paper, if not due to differences in the 

 preservation, may be due to the fact that the bundles 

 represented in the two cases are from different parts of 

 their course. 



The bundle figured by Seward and Binney is at the 

 level of its passage through the mid-cortex, while the 

 figures in the present paper are of bundles passing through 

 the closer cells of the inner cortex. This may very possibly 

 account for the difference in structure, for Bertrand has 

 stated* that in the case of the nearly related Lepidodendron 

 the so-called laticiferous cells increase greatly as the leaf 

 trace bundle passes outwards from the central cylinder. 

 Such an increased complexity might therefore also occur 

 in Lepidopldoios. 



I will now discuss briefly the phloem of Lepidodendron, 

 basing my remarks chiefly on the examination of a very 

 perfect specimen o{ Lepidodendron selaginoides, the species 

 so admirably described by Hovelacque.* As mentioned 

 above, the phloem region in Lepidodendron appears 

 generally even more defective than in LepidopJdoios, and 

 in most cases the phloem region is represented by large 



^ Frank A. B. Lehrlnuh de>- Botanik, 1892, p. 184. 

 - Blass Dr. " Die Physiologische Bedeutung des Siebteils der Gefassbandel. • 

 Jahrb. f. wiss. Bot. xxii., 1891. 

 ^Bertrand, loc. cit., p. 142. 

 * Hovelacque, M., loc. cit. 



