STRUCTURE OF FLOWERS. 99 



manner ; the Clematideas double after the first mode, 

 the Ranunculeae after the second, and the Helleboreae 

 present both. There are species even which become 

 double in both ways : thus, Aquilegia vulgaris, when its 

 filaments are changed into flat petals, forms the variety 

 called stellata ; and when its anthers are changed into 

 horn-shaped ones, it forms the variety caniculata when 

 the horn is erect, and inversa when it is reversed by the 

 torsion of the filament. 



2d. Multiplied Flowers (flores multiplicati) are 

 those where the number of petals is augmented by the 

 increase of the number of rows of floral verticils, or of 

 parts of these rows, and their transformation into petals. 

 In the preceding class the number of parts was not 

 augmented, and there was only transformation ; here 

 there is increase in number, and transformation. All 

 the examples mentioned in the two first divisions of this 

 section belong to this class. 



3d. Permuted Flowers (flores permutati) are those 

 where the abortion of one of the sexual organs causes a 

 remarkable change in the form or dimension of one of 

 the floral envelopes ; thus, the abortion of both or one 

 of them in the Compositae frequently causes a change of 

 form in their corolla ; it sometimes, remaining tubular, 

 becomes larger than ordinarily, as is seen in some 

 varieties of Asters, African Marigolds, &c. ; sometimes 

 it is transformed into a flat strap, which is the most 

 usual case in the Compositae called double in gardens. 

 Similar phenomena are met with in the Guelder Rose 

 (Viburnum opulus), the sterile flowers of which have 

 the corolla larger than the fertile ones : in the natural 

 state the lateral flowers alone present this phenomenon ; 

 but in the cultivated variety all are enlarged, owing to 

 the abortion of the sexual organs. 



Thus the name of double flowers is applied, in ordi- 



ii 2 



