(455) 
attention to the interstaminal secretion of nectar in Anemone nemorosa. 
He stated that the thalamus contains much sugar, and that its inter- 
staminal portion is covered with numerous thin walled papillae, from 
which, under favourable conditions, minute drops of nectar are seen 
to exude. My own investigations have shown me that what BONNIER ') 
observed, may be called a pretty general phenomenon in the order 
of Ranunculaceae i.e. in many genera, nectar is secreted from this 
portion of the thalamus. 
The flowers of Anemone and of Clematis may therefore be con- 
trasted with those of 7vol/ius, as regards secretion of nectar. Here 
the nectar comes into direct contact with the ovaries and it is 
evident, that the numerous drops of honey, which are found every- 
where between the stamens, and which are constantly renewed, 
contribute not a little to the maintenance of a certain degree of 
humidity in the neighbourhood of the ovaries. 
It is remarkable, that in many other Ranunculaceae the nectar is 
secreted in the flower in two places, so that a peripheral and a 
central secretion may be distinguished. It should be noted, that in 
some genera the two methods of secretion are of about equal im- 
portance to the plant, but that in other genera the peripheral one 
is much the least important. 
The flower of Aconitum may serve as an example of a plant in 
which both secretions are of importance for the protection of the 
sexual organs. 
At the beginning of the flowering-period the 3—5 quite glabrous ovaries 
have not yet reached their full development. They can scarcely be 
discerned, as they are enclosed by the numerous stamens. These 
stamens are distinguished by broad filaments, which are very rich 
in glucose, and which, being closely pressed against the ovaries, 
protect the latter against external influences. The sexual organs are 
kept moist by a secretion of nectar from the interstaminal portion 
of the thalamus.?) The sepals and petals are also rich in glucose. 
The two superior petals are metamorphosed to nectaries with long 
stalks and during the time of flowering these secrete a copious 
supply of honey. The two superior, dark blue sepals have coalesced 
to form a helmet-shaped hood, which, as long as the flower is still 
in bud, encloses it for the most part and further, during the 
1) Bonnier, G,. Les nectaires. Annales des sciences naturelles. Botanique. Tome 
VIIL. 1879. p. 141. 
2) Not unfrequently the nectar-drops can be detected on the stamens with a 
simple lens; the presence of nectar between the stamens may moreover be easily 
demonstrated chemically, by depriving a young flower of its calyx and corolla, and 
washing it with water. 
