AUTOGAMY BY THE BENDING OF THE PISTIL. 355 



be dusted with pollen from younger flowers brought by the insects which come in 

 search of honey. The process of outward inflection of the styles is, however, not 

 yet completed, but continues until the stigmas strike against the anthers and take 

 from them some of the pollen still clinging to their surfaces. 



There are also some caryophyllaceous plants (Lychnis alpina, Alsine Oerardi, 

 Cerastium arvense, G. lanatum, Stellaria graminea, S. Holostea) which exhibit, just 

 before the flowers wither, inflections enabling the stigmas to possess themselves of 

 the pollen of the anthers in the same flower. The flowers are incompletely protan- 

 drous. First of all, the stamens inserted opposite the sepals come to maturity while 

 the stigmas in the same flower are still incapable of receiving pollen. The pollen 

 ofiered by these stamens can therefore only be used for cross-fertilization. The 

 next day their filaments bend as far as possible towards the periphery of the flower, 

 and many of them lose their anthers. Meanwhile, the stamens standing opposite 

 the petals grow longer and their anthers dehisce so that their pollen also is ren- 

 dered available for transference by insects. A day later these stamens bend 

 slightly towards the periphery of the flower, but they never lose their anthers, 

 which continue to ofier their pollen till the flower withers. On the fourth day the 

 styles, which have hitherto stood in the middle of the flower, separate from one 

 another, curve over backwards, and, in some species, become twisted into spirals. 

 The stigmas are thus brought into contact with the anthers last mentioned and take 

 up some of the pollen with which they are covered. 



In the Caryophyllacese whose names are given above the inflections of stamens 

 and styles take four or five days; in Mallows (Malva borealis, M. rotundifolia, 

 &c.) the same processes are completed within 48 hours, and in Hibiscus Trionum, 

 and in Ahutilon Avicennce within from three to eight hours. When the flower of a 

 Mallow is just open a sheaf of filaments bearing round anthers covered with pollen 

 may be seen enveloping and roofing over the styles. Soon after, however, the fila- 

 ments of which the sheaf is composed become reflexed and a bundle of styles is 

 then seen occupying the place previously filled by the stamens. The stigmatic 

 tissue has matured in the meantime. The parts of the fiower do not remain 

 long in this position, which is obviously adapted to cross-fertilization by insect 

 agency; the styles coil into the shape of an S and at the same time bend down 

 until the fringe of papillae constituting the stigmatic tissue comes into contact with 

 the pollen of the anthers which have shortly before been lowered by the inflection 

 of their filaments. In Ahutilon Avicennce, which grows abundantly in Hungary 

 on the banks of the river Theiss, the sheaf of filaments does not at any time form a 

 roof over the style, but, from the moment the petals unclose, five slender styles, 

 terminating in spherical red stigmas with velvety surfaces, may be seen projecting 

 above the anthers. Insects alighting upon the velvety stigmas or brushing against 

 them may cause heterogamy at this period; but a couple of hours later the styles 

 curve down, and the stigmas are appressed to the anthers which are covered with 

 an abundant store of pollen. Other Malvaceae, e.g. Anoda hastata, behave in an 

 opposite manner as regards the inflection of the style. In the buds of these plants 



