322 ON THE FALL OF THE COROLLA IN VERBASCUM. 
of the corolla, which is generally covered with hairs, often 
plentiful and sometimes stellate. 
Having set forth these facts, it is easy to see that my obser- 
vations and conclusions do not entirely agree with those expressed 
by Darwin*. He is of opinion that the corolla first separates 
itself from the thalamus, and that afterwards the sepals push it 
off. This opinion would admit of a spontaneous action of the 
corolla in detaching itself from the thalamus; while I believe 
that the fall of this organ is subject to the effort exercised by 
the sepals, and especially by the basal part of them. The 
separating zone, which is not mentioned by Darwin, has not, 
I believe, at this moment and in this case, any other action than 
that of diminishing the resistance of the tissue. It may, however, 
have another function, namely, that of assisting the normal 
detachment of the corolla from the thalamus. 
I would further add that, in order that the irritability of the 
sepals should produce its effect on the corolla, it is necessary that 
the tissues of the flowers should be in a state of turgescence. In 
fact, if we place some cut branches of Verbascum in water, during 
the first and second day we may notice that its flowers are always 
sensitive to shocks, but that, little by little, this sensitiveness 
diminishes, and the new flowers do not suffer from any blow 
aimed at the branch. 
In conclusion I may state that I should liked to have ex- 
amined more species of Verbascum, so as to ascertain whether the 
phenomenon is common to all the species, as I believe to be the 
case, but have not had opportunities of so doing. The species 
on which I have experimented are:—Verbascum Blattaria, 
Cedreti, crassifolium, floccosum, garganicum, Lychnitis, longi- 
folium, macrurum, montanum, nigrum, niveum, orientale, phant- 
ceum, phlomoides, pulverulentum, sinuatum, Thapsus, thapsiforme, 
virgatum, and many of their forms and varieties. In all these I 
have noticed the same phenomenon. If even other species 
do not obey this law, the anatomical study of these would certainly 
be interesting, and might serve as a guide and a comparison for 
later and more decisive results. 
* Darwin, ‘ Forms of Flowers,’ p. 78. 
