Chap. XX VX RELATIVE POSITION OF PARTS. 339 



** down." -^ I have discussed tlie connection between pelorism and 

 a central position, partly because some few plants are known nor- 

 mally to yjroduce a terminal flower different in structure from 

 the lateral ones ; but chiefly on account of the following case, in 

 which we see a tendency to variability or to reversion connected 

 with the same position. A great judge of Auriculas ^^ states that 

 when one throws up a side bloom it is pretty sure to keep its 

 character; but that if it grows from the centre or heart of the 

 plant, whatever the colour of the edging ought to be, " it is just as 

 " likely to come in any other class as in the one to which it properly 

 " belongs." This is so notorious a fact, that some florists regularly 

 pinch off the central trusses of flowers. Whether in the highly 

 improved varieties the departure of the central trusses from their 

 proper type is due to reversion, I do not know. Mr. Dombrain 

 insists that, whatever may be the commonest kind of imperfection 

 in each variety, this is generally exaggerated in the central truss. 

 Thus one variety " sometimes has the fault of producing a little 

 " green floret in the centre of the flower," and in central blooms these 

 become excessive in size. In some central blooms, sent to me by 

 Mr. Dombrain, all the organs of the flower were rudimentary in 

 structure, of minute size, and of a green colour, so that by a little 

 further change all would have been converted into small leaves. 

 In this case we clearly see a tendency to prolification — a term which 

 I may explain, for those who have never attended to botany, to mean 

 the production of a branch or flower, or head of flowers, out of 

 another flower. Now Dr. Masters ^^ states that the central or upper- 

 most flower on a plant is generally the most liable to prolification. 

 Thus, in the varieties of the Auricula, the loss of their proper 

 character and a tendency to prolification, also a tendency to pro- 

 lification with pelorism, are all connected together, and are due 

 either to arrested development, or to reversion to a former condition. 



The following is a more interesting case ; Metzger ^* cultivated in 

 Germany several kinds of maize brought from the hotter parts of 

 America, and he found, as previously described, that in two or three 

 generations the grains became greatly changed in form, size, and 

 colour ; and with respect to two races he expressly, states that in 

 the first generation, whilst the lower grains on each head retained 

 their proper character, the uppermost grains already began to assume 

 that character which in the third generation all the grains acquired. 

 As we do not know the aboriginal parent of the maize, we cannot 

 tell whether these changes are in any way connected with reversion. 



In the two following cases, reversion comes into play and is de- 

 termined by the position of the seed in the capsule. The Blue Imperial 

 pea is the offspring of the Blue Prussian, and has larger seed and 



" Hugo von Mohl, 'The Vegetable 1862, April 29th, p. 83. 



Cell,' Eng. tr., 1852, p. 76. ^3 'Transact. Linn. Soc.,' vol. xxiii., 



" The Rev. H. H. Dombrain, in 1861, p. 360. 



' Journal of Horticulture,' 1861, June ^* ' Die Getreidearteu,' 1845, s. 208, 



4th, p. 174; and June 25th, p. 234; 209. 



