450 Fr. J. Mathiesen. 



found completely surrounded by a compact mass of stereom; 

 only the tissue immediately surrounding the protohadrome 

 remains unthickened and unlignified. 



The anatomical structure in that portion of the stem 

 which bears the rosette-leaves deserves a more special de- 

 scription. 



A transverse section of an axis of an innovation-shoot 

 in its first growth-period, about 3 mm thick, exhibited a 

 distinct Casparian sheath, and in the stele a circle of small 

 vascular bundles, separated by comparatively broad rays of 

 intervening parenchyma; at a depth of about 3 — 5 layers of 

 cells within the cortex there had been formed, even at that 

 point of time, a cork-cambium which had produced a 3 — 6 

 layered cork (Sudan III). 



The transverse section of a 2-year-old rhizome, with its 

 richer 2nd year's leaf-rosette developed, exhibited in its 

 uppermost part a structure similar to that described in the 

 case of the one-year-old shoot, only, the diameter of the 

 organ was larger (about 5 mm), the vascular bundles were 

 more numerous and also individually broader, and they had 

 on the outer side of the xylem-portions a thick cap of wood- 

 fibres. In the basal portion of this shoot, which had been 

 developed the year before, and which was consequently 2 

 years old, there occurred, however, a distinct growth-zone 

 in the vascular bundles, since, either as a direct continuation 

 of the xylem-portion developed during the first year of 

 growth, and furnished on the outer side with a cap of wood- 

 fibres, or else separated from that xylem-portion by 1 — 3 

 layers of thin, unlignified elements, one more xylem-portion 

 was found, which also had a cap of wood-fibres along its 

 peripheral portion, and evidently represented the growth of 

 the 2nd year. Frequently, such xylem-groups of the 2nd year 

 are also developed without being in connection with the 



