420 Vines. — On Epino.sty and Hyponasty . 
crumpled appearance, in consequence of hyponastic growth ; 
but after an exposure for three to five hours to bright diffuse 
light the laminae began to flatten out and to become smooth. 
In both cases the exposure to light was followed by epinastic 
growth of the laminae. With the view of testing the accuracy 
of these statements with regard to the cotyledons of Cucurbit a , 
I kept a large number of seedlings of both C. ovifera and 
C. Pepo in darkness for twenty days (June 10-30), and I found 
that in a large majority of cases the cotyledons separated more 
or less widely, the separation becoming first apparent about 
the sixth day. They were, however, exposed to feeble light 
for a few moments, not more frequently than once in twenty- 
four hours, for the purposes of observation, but this exposure 
can hardly be taken into account. Similar observations on 
the primordial leaves of Phaseolus proved the accuracy of 
Detmer’s statement that the laminae do not become fully ex- 
panded in darkness. 
These observations of mine suffice to prove that, in the case 
of Cucurbita , epinastic growth can take place in darkness, and 
thus, on the matter of fact, Detmer’s theory is shown to be 
untenable. It is open to the further criticism that the pheno- 
mena which he describes are capable of another and a simpler 
explanation. Light certainly promotes the epinastic growth 
of the leaves in question, but there is no evidence that it ini- 
tiates this growth; the effect of light is not ' par atonic as 
Detmer would have it to be, but it is ‘ phototonic The 
epinastic growth of the laminae, when exposed to light, is 
well marked, not because light induces photo-epinasty, but 
because the leaves are in the epinastic stage of their growth ; 
so that when, under the influence of light, they regain the 
phototonic condition and resume their growth, that growth is 
necessarily epinastic. 
The second series of experiments were made on plants other 
than those which Detmer observed, and had as their object 
the determination of the growth-movements of dorsiventral 
members when removed either from the directive influence of 
light alone ; or, by means of the clinostat, from that of both 
