NATURE NOTES 
1 66 
several “ ribs ” just where they are wanted to meet the 
“ drag ” towards the front ; thus, li d ^ 
stands for dorsal, or mid-rib ; in, marginal m m 
rib ; s, a supernumerary rib, the adjoined d d 
diagram of the calyx of Salvia explains 
itself. The strain being all to the fore, ^ 
double cords {m, in) are inserted on that m m 
half ; while the strongest “ drag,” or ^ 
“ pull,” is at s, exactly in front. 
When the uses of stamens and pistil were discovered by Sir 
Thos. Millington (Professor of Botany at Oxford) in the seven- 
teenth century, it was thought that every flower which contained 
both was self-fertilising ; so Linnseus noticed that the stigma 
was, as a rule, hdow the anthers, so that pollen could fall upon 
it, as in the Fuchsia. But a very common feature in insect- 
fertilised flowers is that the pollen is shed before the stigmas 
are matured to receive it; such, indeed, is the case with the 
Fuchsia. This is another hindrance to such flowers setting seed 
so easily as the regularly self-fertilised, as in them the pollen 
and stigmas are ready at, the same time, and always applied 
directly to each other. 
Various features should be noticed in flowers. Thus, if 
insects come, they expect to find honey, and if the flower be 
regular, the honey-glands are formed all round the flower. 
Thus they occur on the receptacle in many plants, as the 
wall-flower, geraniums, &c. ; on the sepals in the lime ; on the 
petals in buttercup, aconite, and larkspur ; on the stamens in 
chickweed and in some species of Clematis; on the pistil in 
marsh- marigold, and several of the Gamopeialcc. Wherever they 
occur they are invariably so situated that an insect alighting 
on a flower can secure the honey in the easiest way. 
If the corolla has a petal in front, then this generally becomes 
enlarged and forms the landing place, as in so many irregular 
flowers, the dead-nettle, snapdragon, &c. If, however, there 
happen to be no petal in front, then the insect alights on the 
stamens, and generally the style as well. They then bend 
downwards at the base, but become upturned at the end, and 
are called ‘‘ declinate,” as in rhododendrons. It sometimes 
happens that they have chosen the stamens in preference to 
the front petal. If this be the case, that petal becomes reduced 
in size, as in Germander speedwell {Veronica Chamerdrys), or may 
disappear altogether, as in the horse-chestnut. 
In every case there are numerous features in the structure of 
the flower which, if carefully observed, will show that they all 
conspire to secure one end, that the insect secures the honey and 
gets dusted by the pollen at the same time ; while the stigma is 
so situated as to strike the insect on the spot — back or front, as 
the case may be — where the pollen has been deposited from a 
previously visited flower. 
Mr. Darwin thought, from numerous experiments in “ cross” 
