H80 ]inrns aiul H o d den, ('omlitidiis inlhi encinj;' regenei-iilion ot'liypocotyl. 



seemed capable of forming a biid, the hypocotyl in some cases 

 was almost completely covered witli buds from base to apex. 



The buds were dovoloped near the l)ase of the hypocotyl 

 in Lniaria^ but in Aiitirr/iiniun and Linuin they were more 

 generally di-stributed. 



As a rille the hypocotyl of Antirrhnium and Limim became 

 bent sometimes as niuoh as 90 ^ and the buds then tended to 

 crowd on the upper side, very few if any were ])roduced on the 

 under side. These buds either developed one after the other or 

 several at a time, but no very detinite arrangement was ever 

 determined. In the majority of cases, however, the second bud 

 developed below the first. 



In several cases the hypocotyl buds were cut off as soon 

 as they fornied, and in this way an almost indefinite numbcr 

 could be forced to develop. They were produced either above 

 or below the origin of the first buds; there was no fixed rule. 

 Seidom more than two of the buds developed into shoots, 

 generally one, but if they were cut off some of the undeveloped 

 buds took their places, or a new shoot was formed on the stem 

 of the old one. As soon as the hypocotyl shoots l)egan to 

 develop they gi'ew very rapidly and took the place of the main 

 axis, which became bent over to one side. After a week or two 

 the undeveloped buds died, the shoots evidently growing at 

 their expense. The hypocotyl buds when produced on uninjured 

 plants of Linaria. as observed by Bernhardi. became the flower 

 stalk and the main stem soon died. One other fact should be 

 mentioned in this connection. Often the seed coats cling to the 

 cotyledons and do not allow them to open. They are not then 

 exposed to the light and cannot serve as assimilating organs. 

 In such cases the hypocotyl produced buds as if it had been 

 wounded. This was tested further by covering the cotyledons 

 with plaster of paris. In this case regeneration took place. It 

 is thus evident that not the wound^j but the absence of the 

 normall}^ present functioning cotyledons give the first Stimulus. 

 The length of time required for the production of such „ad- 

 ventitious" buds differs, widely depending as we will see to 

 some extent upon external conditions. This is not entirely 

 true. In November a large number of seedlings were decapita- 

 ted and kept in the greenhouse. The first buds appeared only 

 after 37 days. The same experiments conducted in January 

 later gave results in one third of that time. 



Anisop hylly. The phenomenon^j varies with different 

 individuals but not with changing external conditions as far as 

 learned. 



Linaria hipartifa splendida develops only a few buds when 

 the cotyledons are removed. Out of 140 individuals, 2 developed 



'■) Goebel. Über Regeneration im Pflanzenreich. (Biolog. Centralblatt. 

 Bd. XXn.) 1902. Weitere Studien über Regeneration. (Flora. 1J)03. p. 132.) 

 2) Küster. 1. c. 



