OBSERVATIONS ON FLOWER POLLINATION 



IN 



EUROPE AND THE ARCTIC REGIONS 



[The abbreviations made use of in the bibliographical references are — where possible — those of 

 the 'International Catalogue of Scientific Literature.' The following are employed in the statements 

 regarding the flower-visits of insects: — nect-lkg., nectar- li eking ; skg., sucking; po-cltg., pollen- 

 collecting; po-dvg., pollen-devouring; freq., frequent. When there is no special reference to 

 locality, Knuth's observations are to be regarded as having been made in Schleswig-Holstein 

 (more especially near Kiel), those of Hermann Miiller in the neighbourhood of Lippstadt (West- 

 phalia), those of Buddeberg in Nassau, and those of Borgstette in Tecklenbnrg.] 



ANGIOSPERMAE 



CLASS I. DICOTYLEDONES 



I. ORDER RANUNCULACEAE JUSS. 



Literature. — Herm. Miiller, 'Fertilisation.,' pp. 69-89; Knuth, ' Bl. u. Insek. 

 a. d. nordfr. Ins.,' pp. 16-17, ' Grundriss d. Blulenbiol.,' pp. 15-17. 



The Ranunculaceae are characterized by a great variety of flower arrangements, 

 such as is met with in but few other orders. The conspicuousness of the flowers 

 is sometimes due to the corolla (Ranunculus, Batrachium, Adonis), sometimes to 

 the calyx (Clematis, Hepatica, Pulsatilla, Anemone, Caltha, TroUius, Helleborus, 

 Eranthis, Aconitum), sometimes to both (Aquilegia, Delphinium), and sometimes 

 even to the stamens (Thalictrum). The colour of the flowers is frequently white, 

 greenish, or yellow (Anemone, Batrachium, Ranunculus, Myosurus, Caltha, Trollius, 

 Helleborus, Eranthis, Actaea), more rarely red, blue, or violet (Pulsatilla, Atragene, 

 Hepatica, Adonis, Aquilegia, Delphinium, Aconitum, Paeonia). The modes of 

 secretion and concealment of nectar are quite as varied as the devices by which 

 conspicuousness is brought about. Nectar may be secreted by the sepals (some 

 peonies), by the stamens (Pulsatilla), or by the carpels (Caltha), but usually by 

 the petals, either at their bases (Batrachium, Ranunculus, Myosurus), or in specialized 

 nectaries resulting from their metamorphosis (Trollius, Helleborus, Eranthis, Aqui- 

 legia, Aconitum, Nigella). Comparison of some of the nectaries in the order 

 (Fig. i) shows a gradual transition from the perfectly simple nectar-pit of Ranunculus 

 to the complex apparatus of Aconitum. In Trollius the petal is much reduced 

 and possesses an elongated nectar-groove above its base, in Helleborus the expanded 



