226 T1TE INDUCTIONS OF BIOLOGY. 



mines these buds into sexual individuals, is given when the 

 nutrition is declining. Conversely, very high nutri- 



tion in plants, prevents, or arrests, gamogenesis. It is 

 notorious that unusual richness of soil, or too large a 

 quantity of manure, results in a continuous production of 

 leaf-bearing, or sexless, shoots. Besides being prevented 

 from producing sexual individuals, by excessive nutrition, 

 plants are, by excessive nutrition, made to change the sexual 

 individuals they were about to produce, into sexless ones. 

 This arrest of gamogenesis may be seen in various stages. 

 The familiar instance of flowers made barren by the trans- 

 formation of their stamens into petals, shows us the lowest 

 degree of this reversed metamorphosis. Where the petals 

 and stamens are partially changed into green leaves,- the 

 return from the gamogenetic structure towards the agamo- 

 genetic structure, is more marked ; and it is still more 

 marked when, as occasionally happens in luxuriantly-growing 

 plants, new flowering axes, and even leaf- bearing axes, grow 

 out of the centres of flowers.* The anatomical 



* Among various examples of this which I have observed, some of the most 

 remarkable were among Foxgloves, growing in great numbers and of large size, 

 in a wood between Whatstandwell Bridge and Crich, in Derbyshire. In one case, 

 the lowest flower on the stem, contained, in place of a pistil, a shoot or spike of 

 flower-buds, similar in structure to the embryo-buds of the main spike. 1 

 counted seventeen buds on it ; of which the first had three stamens, but was other- 

 wise normal; the second had three; the third, four; the fourth, four; &c. 

 Another plant, having more varied monstrosities, evinced excess of nutrition with 

 equal clearness. The following are the notes I took of its structure : 1st, or 

 lowest flower on the stem, very large ; calyx containing eight divisions, one 

 partly transformed into a corolla, and another transformed into a small bud with 

 bract (this bud consisted of a five-cleft calyx, four sessile anthers, a pistil, and a 

 rudimentary corolla) ; the corolla of the main flower, which was complete, con- 

 tained six stamens, three of them bearing anthers, two others being flattened and 

 coloured, and one rudimentary ; there was no pistil, but, in place of it, a large 

 bud, consisting of a three-cleft calyx, of which two divisions were tinted at the 

 ends, an imperfect corolla, marked internally with the usual purple spots and 

 hairs, three anthers sessile on this mal-formed corolla, a pistil, a seed-vessei with 

 ovules, and, growing to it, another bud of which the structure was indistinct. 

 2nd flower, large ; calyx of seven divisions, one being transformed into a bud 



