— 16 — 



remained long and almost unbranched, and reached a length 

 of about 1 cm. Several cells of a filament grown in the 

 dark are shown in Fig. 9 for comparison with those grown 

 under normal illumination. 



In one or two cases the leaves produced structures 

 which were more rhizoid in nature, and these in the cultures 

 both in the light and in darkness. In all of the cultures 

 no buds were produced in the dark, while under normal 

 illumination they appeared after ten days to two weeks. 

 The protonema very soon after its origin from the leaf, often 

 gave rise to a bud as a lateral branch, and numerous cases 

 were observed in which this bud formation occurred from 

 the second protonema cell. This is illustrated in Fig. 8. 



In two cases out of all the experiments which I carried 

 out, I found a protonema productiou from other than the 

 basal cells, so it would seem that the cells of the basal 

 portion of the leaf are more inclined, to produce protonema 

 than those from other parts. In the preparation of the cultures 

 the leaves were stripped from the stem with a pair of 

 forceps, and occasionally portions of the stem were torn 

 away with them. A very abundant production of protonema 

 occurred from these portions of the stem. In order to show 

 whether the power of regeneration was localized more in 

 the basal cells of the leaf, a series of cultures was made 

 in which the entire basal portion of the leaves was cut 

 away. These cultures were kept for six weeks and at the 

 end of that time no formation of protonema had occurred. 

 That the power of protonema production is not confined 

 entirely to the basal cells is shown by the two cases already 

 mentioned where protonema were produced from the region 

 of the tip. Hence, the experiments only show that the leaf 

 cells adjacent to the stem produce protonema more readily. 



Whole plants brought under exactly the same conditions 

 as the detached leaves did not produce any protonema from 

 the leaves, and again plants with the leaves cut away at 

 the tip showed no signs of protonema production. From the 

 experiments it must be concluded that the complete Separation 



