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flowering-period, acts as a protective roof to the two nectaries and 
the sexual organs below them, while the latter are surrounded by 
the remaining sepals and petals. The secretion of nectar has once 
more rendered the flower a moist chamber, in which the sexual 
organs are protected against the dangers of dessication. At first the 
stamens, with anthers bent downwards and closed, lie turned away 
from the entrance of the moist chamber. Later they become erect; 
afterwards they become elongated, and so bring the anthers to the 
entrance of the flower, where they can give up their excess of 
moisture to the air, at least when the latter is not too damp. As 
they dehisce, the stamens again bend downwards with empty anthers. 
The broadened parts of the filaments do not, however, bend in this 
way, but retain their original position and protect the ovaries 
throughout the whole of the flowering period. It is not until this 
stage that the stigmas, which are now fully developed, come to 
the entrance of the flower. 
Although the corollar-nectaries of Aconitum are not much less 
important than the thalamus, as regards secretion of nectar, this is 
not so in all genera of Ranunculaceae, as has already been pointed 
out. In Ranunculus, Batrachium, and Ficaria the corollar-secretion 
is of much less significance and that of the thalamus certainly much 
more important. In Pulsatilla the corollar-secretion is still further 
reduced and in the genera Paeonia, Caltha, Anemone, and Clematis 
the corollar-nectaries no longer occur; here the honey-secretion of 
the thalamus has become of primary importance. 
In Caltha palustris secretion of nectar can be observed in the 
flower in three places: first at the periphery of the thalamus, where 
in the allied Helleboreae the stalked corollar-nectaries are placed ; 
secondly at the interstaminal part of the thalamus; thirdly on the 
wall of each ovary. The ovaries of Caltha are glabrous, but on both 
sides of each ovary there is a spot, covered by hundreds of delicate 
papillae with very thin walls. Each of the latter secretes a minute 
droplet of nectar, and the large drop, which is formed by the fusion of 
the droplets, can easily be detected with a lens between any two adjacent 
ovaries. The parietal papillae here replace the hairs of other genera, 
The extent of the reduction in the peripheral nectar-secretion of 
other genera is best observed in Ranunculus and in Pulsatilla. 
The flower of Ranunculus acer for instance, agrees with that of 
Trollius both as regards the position of the stamens relative to the 
ovaries and the elongation and inward-movement of the stamens. 
The nectar-secretion at the base of the petals cannot contribute to 
the protection of the sexual organs by keeping the flower moist, 
