REGENERATION IN PLANTS 85 



not due to the new part arising on the basal end because there is no 

 other cut-surface, the apical part of some of the pieces was cut off. 

 These pieces, with two free ends, produced new buds only on their 

 basal ends. 



The sexual organs of lunularia are borne on the top of erect 

 reproductive branches having a limited growth (Fig. 9, D\ which 

 carry later the sporiferous branches. The branches have a stalk and 

 a terminal disk. If pieces of the stalk are cut off they do not pro- 

 duce any new parts for a long time, but ultimately each produces 

 from the basal cut-surface, or not far from the basal end, a new bud 

 (Fig. E l ). If the disk is left attached to the piece, the result is the 

 same as before (Fig. D l \ If a twisted part of the stalk is used, new 

 buds may develop at the base and also near the twisted region, as 

 shown in Fig. 9, E 1 . If pieces of the stalk are stuck into the sand, 

 some with the apical end, others with the basal end in the sand, the 

 former produce new buds at the upper basal end, the latter produce 

 buds on the stalk just above the surface of the sand. Pieces that 

 retain the old disk when stuck into the sand (Fig. 9, D) produce one or 

 more buds along the stalk above the sand, often some distance above 

 it. The part buried in the sand does not seem able to develop new 

 buds, and as a result they are produced at the first region of the 

 basal part of the stalk, where the conditions make it possible for 

 buds to develop. 



If the disk is cut entirely from the stalk and placed on moist 

 sand, it produces adventitious buds in the region at which the stalk 

 was removed. Buds are also produced at the bases of the rays that 

 go off from the disk. They arise from the under side of the rays 

 without regard to the position of the disk, i.e. whether it is turned 

 upward or downward. If the rays are cut off they, produce new 

 buds at the base (Fig. 9, F}, and if the outer tip of the ray is also 

 cut off, the new bud still arises at the base, as shown in Fig. 9, F l . 

 These results on pieces with limited growth agree in every respect 

 with those that have been obtained in flowering plants. Vochting 

 thinks that the phenomenon is due in all cases to the limited growth 

 of the parts. Goebel rejects this interpretation, and thinks that the 

 results can be accounted for by the direction of the movement of 

 formative or, at least, of building material. In favor of this view, 

 he points out that in other liverworts the polarity is not shown in the 

 same degree as in lunularia (according to Schostakowitsch), and 

 also that in very old pieces of marchantia, as Vochting has shown, 

 the polarity disappears. In the latter case the attractive action at 

 the vegetative point, to which the building stuff is supposed to flow, 

 is less strong ; and in longer pieces the influence of the apical region 

 may not extend throughout the entire length of the thallus. In favor 



