38 
Newcombe, Sensitive Life of Asparagueplwnosns. 
V. Light as Related to Unfolding of Branches. 
Goethe 1 ) in his “Farbenlehre“, stated that plants grown in 
darkness did not nnfold their lateral buds. Sachs 2 ) contradicted 
this Statement, but Jost 3 ) fonnd that Fagus silvatica did not nnfold 
its lateral bnds in the dark, and Asparagus plumosus follows the 
behavior of Fagus. In the case of seedlings, hewever, and in the 
case of shoots growing from the rhizomes, the shoots being removed 
from light not more than 6 to 8 days before ready to take the 
diageotropic position, the lateral bnds unfold into branches not 
differing greatly from the normal. This unfolding of the bnds of 
the seedlings and of the other shoots named is to be acconnted a 
correlation when compared with the lack of unfolding in other 
shoots of Asparagus, since the shoots which nnfold their lateral 
bnds in the dark are all nearing the end of the growth of the 
main axis. This failure of etiolated shoots to unfold their lateral 
bnds cannot be dne to a lack of sufficient building material, since 
the main axis in many of my etiolated shoots grew for more than 
a meter after the normal time for unfolding the lateral bnds. There 
was therefore enough material for forming the branches, but the 
plant did not dispose its supply of food for the unfolding of the 
lateral buds. Similar results are indicated by Sachs 4 ) working 
with the growth of the leaves of Cucurbita pepo , and by Jost 3 ) 
working with the leaves of some of the Leguminosae and the 
branches of Fagus sylvatica. Sachs’ explanation of the smaller 
size of leaves in the dark is that the leaves become diseased; 
Jost has offered the hypothesis that it is due to the competition 
for food. There is a third possibility at least, that is that the 
plant disposes of its supply of food by correlation, correlation 
here not being equivalent to competition. None of these hypo- 
theses attempts to show the mechanism of Operation. 
The lack of unfolding of the needle-bearing branches of the 
etiolated shoot extends also to the needles. Even in seedlings 
grown in the dark, which unfold the larger branches as well as 
tho in light, the needles are much reduced in size. The etiolated 
seedlings, therefore, agree in behavior with seedlings of most plants 
in failing to develop their assimilating Organs in the dark. 
VI. Light as Related to Twining. 
From the experiments already cited, it is evident that if a 
shoot destined for twining in the light is covered from the light 
x ) Goethe, Farbenlehre. Sämtliche Werke. Cotta’sche Ausgabe 1840. 
Bd. 37. p. 208. 
2 ) Sachs, Bot. Zeitung. XXI. 1863. Beilagen, p. 11. 
s ) Jost, Über den Einfluß des Lichtes auf das Knospentreiben der Rot¬ 
buche. (Ber. d. D. Botan. Gesellsch. XII. 1894. p. 194.) 
4 ) Sachs, Lectures on the Physiology of Plants. Translated by Ward. 
Oxford 1887. p. 532. 
