44 



PRINCIPLES OF PLANT-TERATOLOGY. 



cut off from the edge of the thallus also produced 

 adventitious shoots, but not so rapidly. An old 

 brownish portion of thallus produced a shoot at the 

 basal end. He obtained the same results as those 

 cited above when he cut off pieces parallel to the 

 surface of the thallus, and also when he isolated 

 bits of the internal parenchymatous tissue. Pieces 

 cut from the upper part of gemmae-cups also formed 

 adventitious shoots. These experiments were made 

 with Lunularia vulgaris (PL IV, fig. 3). 



Bolleter obtained, with the liverwort Fegatella 

 conica, much the same results as those of Vochting ; 

 he found that the adventitious shoots always arose on 

 the lower side of the thallus. He induced artificial 



t 

 / 



v 



Fig. 7. — Mnium rostratum. Transverse section of portion of a leaf, 

 showing origin of a bud from a leaf-cell, together with the 

 previously-formed rhizoid. (After Forest Heald.) 



production of gemmae by keeping the thallus for some 

 time in darkness and moisture ; they were formed in 

 the same region as that in which the shoots arose. 



Kreh obtained similar results with several Junger- 

 manniaceous liverworts. 



Gemmae occur normally at the apex of shoots in 

 the liverwort Geplialozia bicnspidata. 



The above are all cases of adventitous shoots occur- 

 ring on other shoots. 



We next come to those of adventitious shoots 

 sprouting on leaves. 



Dozy and Molkenboer describe a very interesting 

 phenomenon in this connection. They observed male 

 plants growing from the upper surface of a leaf of a 



