HISTORICAL DEVELOPMENT OF FLOWER POLLINATION 13 



arrangements, so far as he had recognized them in the flora of Sweden. This 

 work is noteworthy, especially because the attempt is made 'to arrange all the 

 floral adaptations of Phanerogams in a series, according to their natural develop- 

 ment from the less perfect to the more perfect.' 



It is remarkable that Axell doubts the occurrence of protogyny in insect- 

 pollinated flowers, holding that in these only protandrous dichogamy is possible '. 

 On account of this belief, which is contrary to the facts, Axell does not give 

 to protogyny a position of equal importance to protandry, and he is led to 

 doubt the correctness of numerous observations that are opposed to his views. 

 Axell introduces the term ' chasmogamy ' as the contrary to cleistogamy ; and 

 by 'herkogamy' he understands a floral arrangement of such a nature that self- 

 pollination — 'homocliny' in contrast to ' heterocliny ' — is impossible on account of 

 the relative positions of stigmas and anthers. 



At the close of the first part of his work, Axell gives the following summary 

 (according to Loew's ' Einfuhrung,' p. 152): — 



Phanerogamous Flowers. 

 Heteroclinous Pollination. Homoclinous Pollination. 



A. Hermaphrodite Flowers 



\ 



=27 



tn 



■a _c 

 c S 



always 

 occurring 



not always 

 occurring 



5" 3. 



Vt3 ^ 









impossible . I. Cleistogamous necessary 



/ / . II. Chasmogamous .... 

 (a) Homostylous .... 

 (a) Mature stigmas sur- 

 rounded by pollen of 

 same flower . . . 

 (0) Mature stigmas not 

 surrounded by pollen 

 of same flower ... 

 ^ favoured (b) Heterostylous hindered 



(c) Dichogamous 



(d) Herkogamous } p." / 



\ c IB. Unisexual Flowers ,. . impossibl 



/ 



Axell distinguishes the following oecological groups (Loew, op. cit., p. 152) : — 



A. Flowers which are pollinated with the help of an external agent. (Chasmo- 

 gamous flowers.) 



I. Wind-pollinated. {Anemophilous.) 

 II. Insect-pollinated. {Enlomophilous.) 



' Axell starts from the quite unfounded supposition that the corolla generally fades and secretion 

 of nectar ceases as soon as pollen gets on to the stigma, and passes to the equally erroneous 

 conclusion that in insect-pollinated flowers only protandrous dichogamy is possible. (Hermann 

 Miiller, ' Fertilisation,' Eng. Ed., p. 20, note.) 



