T. Holm — Chionophila Bentli. 35 



lar ; there are eight primary mestomestrands with a few 

 vessels, but with neither me s tome-parenchyma nor libri- 

 f orm ; the center of the stele contains a thinwalled, starch- 

 bearing pith. Further down, and below the rosette, the 

 epidermis is more or less collapsed, and replaced by two to 

 three layers of cork, developed from the hypodermal 

 structure of the cortex. The cortex is as above ; in the 

 stele is* no endodermis, but a parenchymatic pericycle, and 

 two concentric bands of leptome, separated by some ten 

 layers of radially arranged parenchyma, a secondary cor- 

 tex. Some secondary vessels may be seen in the primary 

 mestome-strands, and the hadrome thus constitutes much 

 deeper rays than in the internodes above. 



The flower-hearing stem, which is axillary, is two- 

 winged at the base, with the stele circular (in cross sec- 

 tion). It is glabrous and smooth, but the cuticle is, here 

 and there, wrinkled longitudinally. The epidermis is 

 thickwalled, especially the outer cell-wall, and the cortex 

 is also somewhat thickened, and consists of six to seven 

 strata, very open from the wide intercellular spaces, and 

 destitute of starch and crystals. Endodermis is barely 

 distinct (End. in ^g. 7), and the pericycle is merely pres- 

 ent as a single layer of small-celled parenchyma (P. in 

 fig. 7), which is continuous and bordering directly on the 

 numerous small strands of leptome. There are eight 

 primary mestome-strands, containing a few (four) layers 

 of radially arranged, thick^\'alled, and porous mestome- 

 parenchyma. The interfascicular tissue consists of lep- 

 tome, and three to four layers of radially arranged, thick- 

 walled parenchyma. The pith is solid, homegeneous, with 

 no starch or crystals {f^g. 7). In the Avings of the stem is 

 only thinwalled cortex, no collenchyma being developed. 



This portion of the flower-bearing stem was subter- 

 ranean, but the structure of the upper, aerial internodes 

 is about the same. However, small hairs with cuticular 

 pearls {fig. 9) occur on the internodes, and the cuticle is 

 more wrinkled. The epidermis is more thiclrwalled, the 

 cortex contains chlorophyll, and is very open from lacunae 

 of quite considerable width, but otherwise the inner tis- 

 sues are as described above. 



Characteristic of the stem is thus the complete absence 

 of collenchyma and stereome, the only strengthening tis- 

 sue being represented by the thickwalled, interfascicular 

 parench^maa. 



