( 316 ) 
surface are more pointed, have thicker walls and are marked with 
protuberances. 
Next morning there were numerous clear drops, both at the apex 
and on many of the teeth, but only on those leaves which had not 
bent over and become free of the bud; the apices of the following 
third pair of leaves also showed the formation of drops. 
In addition to the secretion at the teeth and at the apex, which 
is to be ascribed to the same cause as in Philaclelphus coronanus, 
namely to the secretory action of the epidermal and sub-epidermal cells, 
we observe, in addition, that the hairs with which the leaf is covered, 
behave as glands and secrete the water with which the young leaves 
are covered. 
In Hydrangea campanulata the mode of watersecretion is not 
very different from that in H. pabescens. 
Weigelia rosea variegata. 
In this Weigelia the young leaves have both halves rolled up to 
the middle vein. Secretion of large, clear drops of water takes place at 
the apex of the young leaves and at the apices of the teeth, which 
anatomically agree with those of Hydrangea. The leaf surface, espe¬ 
cially the upper one, is thickly covered with trichomes of various 
sizes, shaped like a pedunculate cushion (Kopfchendriisen), which is 
so often found in watercalyces; they occur especially on the basal 
half of the leaf They secrete abundantly so that the space enclosed 
by the rolled-up leaves is filled with water. 
They do not occur in the very youngest leaves. The youngest 
leaves, of which the teeth are not yet formed, only have a covering 
of long unicellular hairs, of which the rounded base takes part in 
the secretion of water. 
In an experiment made in the end of May, when the leaves of 
the bud were fully grown, no formation of drops took place under 
the circumstances mentioned. 
Corylus Avellana L. 
In Corylus Avellana every leaftooth bears at its apex a large, 
compound, almost cylindrical gland, by way of appendix. The teeth 
are placed in two rows, one of which consists of much smaller 
teeth which are pointed inwards; these smaller teeth also have the 
character of mucilage-glands. 
In the branch, on which the experiment was made, the buds were 
just beginning to unfold. The outermost leaf had already liberated 
itself from the bud and was bent outwards; the glands at the apices 
