48 
POPULAR SCIENCE REVIEW. 
then these marauding bees would not wait for that occurrence, 
but would make holes in the buds. I therefore gathered 100 
flower buds, as nearly open as might be, in the same place 
and on the same day as had furnished the 100 open blossoms. 
In 89 of them there was no hole, in 11 only was one present. 
It seems a fair inference from this, that nectar is not secreted 
until the flower is on the point of opening. It is plain how 
accordant this is with the view I have taken of the use of nectar ; 
namely, that it attracts insects to enter by the mouth of the flower. 
Among the figworts there are other species nearly allied to the 
two I have described — bartsia, for instance, and yellow rattle 
(Rhinanthus ) — in which there is a very similar arrangement of 
the anthers and a similar method of fertilisation. 
The coherence of the anthers, and the mechanism for fecun- 
dation in the species as yet mentioned, may be called ex- 
ceptional. In most didynamia there is a simpler arrangement, 
and this must now be considered. 
The flower which I shall take as an example — the woodsage, or 
Teucrium Scorodonia — t hough not very attractive in appearance, 
presents some points of interest. Figs. 3, 4 will give a sufficient 
notion of its shape. It will there be seen that the flower differs 
from most of its tribe in having no hood formed by the upper 
lip. The stamen and pistil are, however, protected while the 
flower is in bud by the lower lip, which is so bent back as to 
cover them in and shut out wind and rain, while it also prevents 
the premature visits of importunate insects. So soon as the 
anthers are ripe, this lip turns over and becomes the landing- 
place of insects. The stigma is at this time immature, and lies 
behind the stamens out of reach. The stamens, on the other 
hand, incline forwards (fig. 3), so that the ripe anthers, which 
dehisce in front, are in such a position that the bees, which 
visit the flower in abundance, cannot fail to rub the back of 
their heads against the pollen. So soon as the stigma is ripe, 
the stamens, which have now shed all or most of their pollen, 
retire backwards, bending over the upper lip ; while the style 
comes forwards, and occupies the position which before was held 
by the anthers (fig. 4). It is plain that this arrangement brings 
about the fertilisation of the older by the younger flowers, an 
occurrence of which we have numerous examples. 
Let me now notice another point. The stamens in this 
flower are of unequal length. Two are long, two short, or, in 
botanical language, the flower is dfdynamous. Can any use be 
ascribed to this arrangement? I think there can. Were all 
the stamens of equal length, the hinder pair would be impeded 
by the front pair, and the pollen of the former would be wasted 
on the posterior surface of the latter, and never come into contact 
at all with the bee. This evil is avoided by their longitudinal 
