196 



ILLINOIS STATE ACADEMY OF SCIENCE 



That even these injuries and disturbances are not nec- 

 essary in order that shoots may develop was discovered 

 in the plants at hand. In the Botany Greenhouse, notch 

 growth appeared on the leaves of several plants which 

 apparently were in normal condition. This development 

 has been found on the leaves of B. calycinum as well as 

 on those of B. crenatum and on both old and young 

 plants. An interesting feature noted in the species caly- 

 cinum was that, while in the notch growth on leaves sep- 

 arated from the plant roots appeared before the shoot, 

 the reverse order of development was true on leaves 

 attached to the plant. 



For more ready comparison, the results with B. caly- 

 cinum obtained by Loeb and those with B. crenatum ob- 

 tained by the author are given in the following table. 

 Unless otherwise stated, the results given for B. caly- 

 cinum are those obtained by Loeb ; those given for B. cre- 

 natum were obtained by the author. Where no time is 

 given for calycinum it was the same as for crenatum. 



Leaf Time B. crenatum 



1 10 da. Much notch growth, 



aerial and submersed. 

 5 wk. Shoot on petiole in one. 



2 10 da. Shoot from opposite or 



both axils in all ma- 

 ture leaves. 

 In very young, shoot 

 from adjacent axil in 

 each. 

 5 wk. A few notch shoots and 

 roots. 



3 10 da. Shoot from each axil. 



Notch growth on most 

 leaves. 

 5 wk. Shoots and roots as 

 large as in leaf 2. 

 Notch growth as vig- 

 orous as in leaf 1. 

 10 da. Abundant notch growth 

 the same as in leaf 1. 



7 10 da. No growth. 



4 wk. 2 — no growth. 3 — shoot 

 on petiole and some 

 notch growth. 



8 10 da. 4 out of 6 no growth. 



1 — adjacent shoot. 1 — 

 adjacent shoot and 

 notch growth. 

 4 wk. Adjacent shoots in each. 

 Some notch growth. 



9 Same as leaf 3. 



10 5 da. 4 — basal shoots; 1 — 

 basal and apical node 

 Shoots, 



Time B. calycinum 



Roots and then shoots 

 on submersed portion. 

 Shoot on petiole of 2. 



(Author's results) 

 Opposite axillary shoots. 



No notch growth. 



Roots and shoots on sub- 

 mersed portion. Not 

 quite as quickly as in 

 leaf 1. 



4 shoots from submersed 

 portion. Adjacent axil- 

 lary bud. 



Roots and shoots under 

 water, similar to leaf 

 1. 



Roots on many sub- 

 mersed portions. Shoot 

 on one. 



A few had some roots 

 and shoots on sub- 

 mersed portion. 



Same as leaf 3. 

 Notch roots and shoots, 

 no axillary shoots. 



