( 454 ) 
the liumidity of the flower in Fritillaria does not interfere: with 
the dehiscence of the anthers, because these are outside the flower, 
this is not so in Trollius, where the dehiscence of the anthers is 
equally dependent on the evaporation of superfluous water into the 
air, for in Trollius the stamens are enclosed within the calyx. 
This is the explanation of the remarkable phenomenon, that the 
stamens, beginning with those of the outer whorl and then grad- 
ually from the periphery to the centre, become elongated soon after 
the opening of the flower and bend inwards, until their anthers are 
near the opening; tle anthers of the inner staminal whorl then come 
to lie immediately above the stigmas. If one places a young flower 
in a closed glass box, the phenomenon may be followed step by step, 
and one observes at the same time, that as long as the flower re- 
mains in the glass box, the anthers remain closed. In an open box 
on the other hand, the anthers are seen to dehisce as soon as they 
have come under the opening of the flower, and their pollen is seen 
to be seattered on the stigmas. Observation in the field likewise 
proves, that the anthers remain closed in damp weather. 
Honey is not secreted in any place other than the petals. In the 
main the arrangement of the flower is quite like that of Fritillaria. 
The closed condition of the corolla can hardly be explained other- 
wise than as a device to prevent the rapid evaporation of the nectar 
into the air and is connected with the erect position of the flower’). 
As a second example of the methods of nectar-secretion in 
Ranunculaceae, | now choose the flowers of Clematis and of Anemone, 
which do not possess petals, but where the calyx takes the place 
of the corolla, and where no nectar is observed on the periphery of the 
flower. This is the reason, why they are referred to as nectarless 
plants in the literature on the biology of the flower. That this is by 
no means correct, is at once evident when we wash the ovaries, which 
are thickly covered with silky hairs, for a moment with a drop of 
distilled water on a slide, and then warm the water with a drop 
of Frarine’s solution; we then obtain a strong glucose-reaction, 
proving that the hairy covering of the ovary is saturated with nectar. 
Further investigation shows, that this nectar is derived from the 
interstaminal portion of the thalamus. 
The droplets of nectar, which are secreted here, are sucked -up 
between the stamens and the ovaries and are retained, especially by 
the hairy covering of the latter. 
I must now recall that many years ago, Bonnier already drew 
1) | believe that this is also the explanation of the closed flowers of Calceolaria, 
Fumariaceac, Antirrhineae, Rhinanthaceae etc. 
