i893. HYBRIDITY IN PLANTS. 203 



on several species of Artsfolochia, that when flies enter the chamber 

 formed by the lower part of the perianth, and become dusted with 

 pollen, in their efforts to escape again from the chamber they come 

 into contact with these hairs, and thus lose, before they pass to 

 another flower, almost every grain of pollen. In A. harhata at 

 least 600, and in A. oviiithocephala about 6,000 pollen-grains 

 would be required for the fertilisation of all the ovules 

 in an ovary. Out of a very large number of flies captured in these 

 chambers, only a very few showed the presence of even a small 

 number of pollen-grains adhering to them. On the other hand, both 

 these two species and^. elegans are abundantly fertile when pollinated 

 with their own pollen. He concludes, therefore, that these species at 

 least are self-pollinated. Herr Burck also points out the interesting 

 fact that in Arisiolochia the true stigma and style are abortive, and 

 that the so-called stigmatic surface consists of the connectives of the 

 anthers which have coalesced by their sides into a cup, are provided on ' 

 their margins with papillae, and have assumed the functions of a 

 stigma. In the instances just named, and in others of the same kind, 

 it is an allowable hypothesis that the bright colour or sweet scent of 

 the flower is a survival from cross-pollinated ancestors which has 

 now lost its meaning. But this will not apply in other instances. 

 The hazel and the larch have, it is true, unisexual and therefore 

 necessarily cross-pollinated flowers. But they are not visited by 

 insects, and are universally regarded as typical examples of wind- 

 fertilised plants. What, then, is the object of the bright red colour of 

 the styles of the one and of the scales of the opening cones of the 

 other? It cannot be a survival, since the Corylaceae and the Coniferae 

 are both unquestionably archaic forms of life. Bright colours, indeed, 

 appeared very earlj^ in the evolution of plant-life. How are we 

 to explain the brilliant red of the sporange of Sphagnum ; or the bright 

 pigment of the antherid or "globule" of the Characeae ; or the 

 brilliant colour of species of Peziza or Boletus ? Does Nature love 

 beauty for its own sake ? 



Prominent among those who advocate the anti-Darwinian view 

 of the prevalence of self-pollination, is Mr. Thos. Meehan, of Phila- 

 delphia, a botanist of great experience in the cultivation of plants. 

 He adduces a large number of American plants in which he asserts 

 this mode of pollination to be the rule, among others, in Amsonia 

 Tabernccmoiiiana, belonging to the Apocynaceae, in which the flowers 

 are showy and abundantly fertile, but their structure is such that 

 no insect, not even a thrips, can gain entrance to the nectary. The 

 mouth of the corolla-tube is so densely matted with hairs that if 

 the pollen-clothed tongue of an insect were thrust through the mass, 

 it would be completely cleansed ; nor is there any room for the 

 tongue to pass the capitate stigma. To effect pollination the anthers 

 curve over and rest upon the stigma. Other examples of habitual 

 self-pollination are given in Symplocarpus fortidus, belonging to the 



