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TTTE JOURNAL OF BOTANY 



as a common visitor, though frequent in Sussex. It rarely occurs in 

 North Wales, and is thus of no importance in regard to the "pollination 

 of Primroses in Wales. 



Summary. 

 The conflicting views of various writers in regard to the pollina- 

 tion of the Primrose may be to some extent due to the fact that the 

 influence of climatic conditions has not always been taken into 

 account. No one who has carefully studied flowers and their pollina- 

 tion in the field can fail to be convinced of the necessity of calm, warm, 

 and sunny weather, if such investigations are to be of value. This is 

 especially true in the case of animal-pollinated species, as Sprengel 

 {Das enidechte Geheimnis der JSJ~atur, p. 23; 1793) long ago pointed 

 out; Midler (Die Alpenbhtmen, p. 547; 1881) has also emphasised 

 its extreme^ importance, and Weiss (I. c.) has also called attention to 

 the fact. The absence of any previous systematic nocturnal observa- 

 tion has also contributed to the uncertainty, as night-watching in 

 North Wales has resulted in a considerable 'addition to the visitors 

 previously recorded. The investigations recorded above, extcndin<>- 

 over several seasons, have practically doubled the list of visitors 

 hitherto recorded for the Primrose. Cold winds, wet weather, and 

 low temperatures are also found to exercise an adverse influence on 

 nocturnal visitors. Night-observations in Flint and Denbigh nega- 

 tive the statement of Darwin quoted above "that the pollination of 



the Primrose must depend almost exclusivelv on moths." I 



have failed to detect a single moth as a visitor, and conclude that 

 nocturnal Lepidoptera may be ruled out of account. Bell (op. cit. 

 pp. 32-3) has remarked on the scarcity of night-moths at the season 

 when the Primrose is usually in bloom. 



Moths only appear to have been observed (Knuth, op. cit.) as 

 floral visitors to a single member of the genus, Primula lonqiflora 

 AIL, a handsome Continental species. This, however, has variegated 

 pink flowers which are not adapted to nocturnal lepidoptera, but are 

 visitedby the diurnal, Macroc/Iossa s'tellatarum. Darwin may have 

 had this fact in mind when endeavouring to account for the efficient 

 pollination of the Primrose, which was necessarv to substantiate his 

 interpretation of heterostyly. Typical moth-flowers, as Spren<»vl 

 (I. c. p. 16) pointed out, are devoid of nectar guides. Although the 

 colour and the narrow tubular nectariferous corolla are to some 

 extent suggestive, the variegation and the comparative absence of 

 odour do not favour moth-pollination in the Primrose. 



The chief diurnal visitors which regularly visit the flowers under 

 favourable climatic conditions are the Diptera Bombylius major and 

 (in Southern England) B. discolor, the bees Andrena Gwynana and 

 Anthopnora pilipes, and Coleoptera of the genus Meligethes. The 

 humble-bees— Bombus Tiortorum and B. terrestr is, —and other animals 

 which are less frequently associated with the flowers or show little 

 structural adaptation to this end, can onlv be regarded as occasional 

 or subsidiary agents in the pollination of the Primrose. Pollination 

 may also occur at night time through the agency of Gasteropoda 

 (snails and slugs), earwigs, certain Coleoptera (especially Otiorln/n- 

 chus, lachyporus, and Bhayonycha fuscicornis O.), and the Isopoda 



