( 310 ) 
of Spathodea campanulata the same Inchoates which secrete the 
calyx-water inside I he flower and he could show experimentally that 
under favourable conditions these latter are also able to secrete water. 
In addition Haberlandt described in other plants metamorphosed 
epidermal cells and multicellular trichoraes on the surface of the 
leaves, which under certain conditions functioned as water-glands. 
Haberlandt’s observation regarding the occurrence of water-glands 
on the leaves was soon followed by others. 
Nestler gave a detailed account of the water-secretion from 
epidermal glands in Phaseolus multiflorus and in Malvaceae and 
von Minden ’) in Nicotiana and Glaux maritima. 
With regard to one very important point, viz. the conditions under 
which water-secretion from the glands takes place, Haberlandt, 
however, reached a conclusion which is not in agreement with the 
results of earlier observers, particularly with those of Gardiner on 
the water-secretion from the multicellular epidermal glands on the 
leaf surface of Limoniastrum (Stalice) monopetalum and from the 
water-glands of Polypodiaceae; nor has Haberlandt’s conclusion been 
confirmed by the above-mentioned later investigations. 
Starting from the view that the secretion of water would serve 
to prevent an overloading of the leaf with water and an injection 
of the intercellular spaces, Haberlandt regarded the glands on the 
surface of leaves and also those of ferns and similar glands as 
regulators of the water-content which only begin to act when the 
hydrostatic pressure in the vascular-system, i.e. the so-called bleeding- 
pressure, has reached a certain height through interrupted transpiration. 
Nestler *), to whose investigations on water-secretion in leaves of 
Phaseolus multiflorus we owe the certain knowledge, that the water 
is really excreted by the glands (he succeeded in directly observing 
under the microscope the excretion of drops of water from the ceils 
of the glandular hairs), was unable to confirm this view 8 ). He 
found that the secretion of water is independent of root-pressure, as 
Gardiner had also found for Limoniastrum and for ferns. The drops 
of water appeared on the surface of cut leaves which were kept in 
a space saturated with aqueous vapour. 
*) M. von Minden, Beitrage zur anatomischen und physiologischen Kenntnis 
wassersecernirender Organe. Bibliotheca botanica Heft 46. 1899. 
8 ) 1. c. Bd. CVIll. 1899 und Berichte der deutsch. bot. Gesellsch. Bd. XVII 1899, 
S. 332. 
8 ) That we cannot always deduce from the presence of glands that any water 
which* may occur has been secreted by those glands was shown by Nestler s 
investigation'of water-secretion in Boehmeria (Sitzungsber. Wien Vol. GVUI, p- 690 h 
