4 Coward, Structure of Syringodendron. 



remains of protoplasmic activity, such as mucilage, in 

 which case these sections certainly lend support to the 

 view that the parichnos strands remain, and enlarge as 

 secretory organs. In the impression specimens, however, 

 the scars have numerous little lumps or ''roughnesses," 

 which are probably these groups of cells preserved, and it 

 seems much more likely that these cells have once been 

 sclerised, but the thickening of the walls has been so 

 acted upon by acids that it has swelled up, and is no 

 longer recognisable as such. In view of the persistence 

 and enlargement of the parichnos strands there is 

 reason to suppose that they were respiratory in function, 

 and the sclerised patches may have served the purpose of 

 support. The strands may then be directly compared 

 with the lenticels of Dicotyledons with which they would 

 be analogous though not, of course, homologous. 



In the sections and in the impression specimens which 

 shew a similar stage of decortication, no trace of the 

 vascular strand which accompanies the parichnos to the 

 leaf can be distinguished. The vascular tissue, having 

 become useless when the leaf has fallen off, has not 

 continued its growth, and while the remains of the bundle 

 become less conspicuous, the enlarged parichnos strands 

 become more so. In different specimens of impression, 

 material, every gradation of size of parichnos strand, can 

 be traced from one sixteenth of an inch in diameter on 

 small stems, to an inch in the largest ones. 



Comparing these various stages with the sections 

 under consideration, there seems to be no doubt that 

 they agree, and the structure material really must be that 

 of Syringodendron ; and although we have thus obtained 

 sections of the structure material of the enlarged parichnos 

 strands, their function is not entirely settled by it, though 

 the evidence at present seems greatly in favour of the 



