Conditions influencing regeneration of hypocotyl. 



By 



Prof. George P. Burns 



and 



Mary E. Hedden. 



(Witli 4 Images in tlie text.) 



It has long been known tliat tlie hypocotyls of many seed- 

 lings will prodiice, under some conditions, one or more ..adventi- 

 tious" shoots.^) 



The writers cited, worked witli iminjured seedlings and 

 established the following facts. 



First, that many seedlings produce „adventitious'' buds 

 normally. Irmiscli points out tliat abont 50 "/o of tlie seedlings 

 Anagallis arvensis do this. 



Second, that many seedlings produce these buds onlj'- 

 under exceptional conditions. Wydler found tliat only those 

 seedlings which he kept in crocks produced hypocotyl buds, 

 those in the open never doing so. Braun found the same and 

 agreed with Irmisch and others, that an abundance of water 

 might l)e the causal factor. 



1) Röper, Enunieratio Euphorbiarum. 1824. 



Bernliardi, Linuaea VII. 1S3'2. p. 572. 



Cliavannes, Monographie des Antirrliinnm. 1833. 



Wydler, Bot. Ztg. 185U. Nr. 22. Flora. 185G. Nr. 3. 



Bemer Mitteil. Nr. 485—487. 



Irmisch, Über die Keimung und die Erneuerungsweise von Convol- 

 vulus sepium und ('. arcensis, sowie über lij-pokotylisclie Adventivknospen 

 bei krautartigen phaneroganien Pflanzen. (Bot. Ztg. Bd. XV. 1857. p. 433. 

 Flora. 1853. p. .522. Flora. 1857. p. 439.) 



Braun. Adventivknospenbilduug am ersten (liypokotj'len) Stengel- 

 glied. (Sitzungsber. der Naturf.-Ges.. Berlin. 1870: vergl. auch Bot. Ztg. 

 Bd. XXVIII. 1870. p. 438.) 



Zabel, Entwicklung der von der Adise abgetrennten Keimblätter. 

 (Bot. Jahresber. Bd. X. 1.^2. j). 82.) 



Bej^erinck. Over regeneratieverschynselni aan gespleten Vegetation 

 punten van stengelsen over Ijekervoruung. (Bot. Central d1. 1883. p. 231.) 

 Beobachtung und Betrachtungen ül)er Wurzelknnspen und Neben wurzeln. 

 Amsterdam lS8f). 



