Vol XLIIL, Art. 1.— K. Yendo : 



the cross sections, to the perimedullary cells. Some other trumpet 

 hyphae, however, remain thin-walled and may contain a hyaline, 

 highly refracting, cartilaginons substance on both sides of the 

 sieve plates. This substance turns yellowish in the dried speci- 

 mens, and stains deep blue by aqueous anilin blue, proving in 

 every point the callus formation observed by Sykes^) (Plate XVIII, 

 fig. 15, 16, 18). 



The fibrous cells interposed between the large cylindrical cells 

 of the perimedullary tissue disappear by degrees towards the peri- 

 phery of the stipe, and the cylindrical cells become at the same 

 time disposed in a more or less regular, radial direction. Hence, 

 in the cross sections, this part appears under the microscope like 

 a parenchymatic tissue. 



From the outer part of the perimedullary tissue the cortex 

 begins quite abruptly. It occupies a greater part of the thickness 

 of the stipe and assumes the part of the xylem of a tree. The 

 term cortex does not at all express the true character of the 

 tissue but has been invariably applied to this part by former 

 writers. It is marked by having cells of much smaller diameter 

 than the tissue lying just inside, and by having very few fibrous 

 cells. The inner part of the cortex has the cells generally irregu- 

 larly disposed and some fibrous cells may still be found interposed 

 between them. In the outer part, the cells become gradually 

 regularly radiate and narrow-lumened until it passes quickly into 

 the epidermal layer. In the longitudinal sections, the inner cortex 

 differs from the outer by having the cells longitudinally elongat- 

 ed but much undulating, while in the latter they are stretched 

 transversely (Plate XVIII, fig. 12). 



1) SïKEs : Anatomy and Histology of Macrocystis pyr'ifera and Lammaria sacckarina, p 

 320. Cfr. PI. XIX, fig. 19, 21, &c. 



