JOURNAL 
OF THE 
Royal Horticultural Society. 
Vol. XIX. 1896. 
Part III. 
ETIOLATION AS A PHENOMENON OF ADAPTATION. 
By Feancis Daewin, F.E.S., F.E.H.S., &c. 
[Read July 9, 1895.] 
Etiolated plants differ from normally grown specimens — 
(1) in the absence of chlorophyll ; * (2) in form. It is with the 
last-named phenomenon — the deformity of etiolated plants — that 
I am concerned. 
The deformity varies greatly in different plants : the best 
known appearances are those presented by a seedling bean or a 
potato tuber which has been allowed to germinate in the dark. 
The shoots differ notably from light-grown shoots in two par- 
ticulars — viz. the great length of the internodes and the dwarfing 
of the leaves. This, as is well known, is not the only form 
assumed by etiolated plants, although certain theorists have built 
up hypotheses which meet no other case. If one of the cereals 
is forced to grow in the dark, its leaves are not dwarfed, but, on 
the contrary, elongated. The same thing is true of some other 
monocotyledons as well as of certain dicotyledons with radical 
leaves. These two types of etiolation will serve for a preliminary 
* With certain ^Yell-kno^vn exceptions. 
B 
