RECENT OBSERVATIONS ON THE FERTILISATION OF PLANTS. 341 
next flower (of the same species) which it visits, it will also 
almost inevitably strike against the stigma and leave some of 
the pollen-grains behind on it, which will then put out their 
tubes and fertilise the ovules. But inasmuch as in by far the 
majority of cases the stigma is not “ receptive,” or in that 
papillose and viscid condition in which alone it incites the 
emission of the pollen-tubes at the same time that the pollen is 
being discharged from the anthers in the same individual 
flower, provision is thus made for that “ cross-fertilisation ” 
which we have already spoken of as the general rule; and 
indeed in many cases no other mode of fertilisation is possible. 
Headers of botanical literature are now so familiar, both from 
articles in this journal (Popular Science Keview, July 1869, 
p. 261, and Jan. 1870, p. 45) and elsewhere, with illustrations of 
the infinite variety and beauty of the contrivances for the cross- 
fertilisation of flowers by insect agency, that we do not propose 
to give many more here. The simple arrangement by which the 
pistil and stamens in the same flower arrive at maturity at dif- 
ferent times may be noticed without difficulty by the most care- 
less observer. It is only necessary to gather the common rib-grass 
{Plantago lanceolata) to observe that the feathery stigmas are 
produced from the still half-closed bud before the stamens are 
nearly mature ; and the same is the case with the water-side fig- 
worts (^Scrojphularia nodosa and aquatica). The reverse, how- 
ever, is far more common, and may be well seen in almost any 
plant belonging to the natural order Caryophyllacese, as, for 
example, any of the common species of stitch-wort (Stellaria 
Holostea or graminea), where the anthers have actually dropped 
off the filament before the stigmas have acquired their receptive 
condition. The hare-bell, or any other species of Campanula, 
wild or cultivated, will illustrate the same phenomenon. A 
singular circumstance connected with these arrangements is that 
closely allied species of the same genus exhibit sometimes exactly 
opposite peculiarities in this respect ; and it is even uncertain 
whether the same species does not vary under different condi- 
tions. A very interesting account of the phenomena presented 
by a number of plants of the pea-tribe belonging to the na- 
tural order Leguminosse, by Mr. T. H. Farrer, will be found in 
“Nature,” vol. vi. We may give a single very good example 
of this in the two common mallows, illustrated by fig. 1 in our 
plate, which are taken from a book, to which we shall have 
occasion to refer again, by Dr. H. Muller, of Lippstadt,* on the 
Fertilisation of Flowers by Insect Agency. In the large mal- 
low (^Malva sylvestris) the stamens are collected together into 
* Die Befriichtung’ der Blumen durch Insekten und die gegenseitigen 
Anpassungen beider. Von Dr. Hermann Miiller.” Leipzig, 1873. 
