262 Transactions. — Botany. 



sometimes in the stigma. On the other hand, heterostyled 

 flowers may not exhibit any great difference in the length of 

 either style or stamens. 



Hottonia palustris exhibits only two forms of flowers, and 

 therefore belongs to the group of heterostyled dimorphic plants. 

 In Lythrum, Oxalis, and one or two other genera heterostyled 

 trimorphic flowers are developed : in each form there are two 

 sets of stamens, and the style varies in length reciprocally with 

 the stamens, the long-styled form having the shortest stamens, 

 and the short-styled form the longest stamens; one set of 

 stamens in each form is of the same length as a set in one of 

 the other forms. No pistil can be fully fertilised except by 

 pollen from stamens corresponding to the length of its style, 

 but the pistil of either form may be fertilised by pollen from 

 one or both the other forms. 



The arrangements for cross-fertilisation in the New Zealand 

 species of Fuchsia are much less complicated than in Lythrum 

 or Oxalis, and combine with heterostyled trimorphism a 

 marked tendency to unisexuality, the long-styled form in each 

 species being practically a female flower, although in some 

 instances capable of self-fertilisation." 



The variation in the form of the flowers of the New Zea- 

 land fuchsias has been long recognised, although even yet it 

 can scarcely be said to be fully understood. Sir Joseph 

 Hooker, under the description of Fuchsia excorticata, in the 

 "Flora Nov.-Zel.," volume i., page 56 (1853), remarks, 

 " The stamens vary much in length, being sometimes quite 

 included"; and was so much impressed by the short-styled 

 form of F. procumbens that he was led to consider it a distinct 

 species, and described it as such under the name of F. Jeirkii. 

 After pointing out that it was impossible to distinguish the 

 two plants by the leaves alone, he adds, " In the flowers they 

 differ widely. ... At first I was inclined to think that 

 these differences might be sexual ; but I should rather regard 

 them as diagnostic of two representative species that possibly 

 had a comparatively recent origin." t Mr. G. M. Thomson 

 detected two forms of flowers, one of which he rightly stated 

 to be hermaphrodite in structure but pistillate in function .| 

 Unfortunately, with other southern botanists, he failed to dis- 

 tinguish between F. colensoi and F. procumbcns, and conse- 

 quently has no distinct reference to the heterostyled flowers of 

 the latter. 



All the New Zealand species agree in having alternate 

 leaves and axillary solitary flowers, although in F. cxcorti- 



* If it were not for the two forms of hermaphrodite flowers, the New 

 Zealand fuchsias might be termed gynodicecious. 

 t Ic. PL, 3rd ser., i., G7. 

 X Trans. N.Z. Inst., vol. xiii. (1880), p. 264. 



