150 



HYPOTHESIS OF THE DEVELOPMENT OF 



FIG. 78. 



but behold the secret of their difference ! While the former 

 plant remains in the water, its leaves are all finely cut, and 

 have their divisions hairy ; but when the steins reach the sur- 

 face, the leaves developed in the atmosphere are widened, 

 rounded, and simply lobed. Should the seeds of this water- 

 plant fall upon a soil merely moist without being inundated, the 

 result is the ranunculus hederaceus the presumed distinct 

 species with short stalks, and none of the leaves divided into 



hairy cut work ! l To come 

 to a more familiar instance. 

 The various bread-forming 

 grains, wheat, barley, oats, 

 rye, are found to be resolvable 

 into one. If wheat be sown 

 in June, and mown down so 

 as not to be allowed to come 

 to ear till the next season, the 

 product will be found to con- 

 sist partly of rye or some other 

 of the cereals. Oats have in 

 like manner been transformed 

 into rye, barley, and even 

 wheat. Till a recent period, 

 this phenomenon was doubt- 

 ed ; but it has been tested by 

 experiment, and reported on 

 by so many credible persons, 

 that it can no longer be re- 

 jected. 2 And it appears, that 

 poorness of soil has the same 

 effect as mowing down. One 

 observer states that, in a field 

 of wheat, near Lucerne, he 



1 Lamarck's Philosophic Zoologique. 



2 " I have had occasion to make a careful comparison of the textures 

 of the seed-coats of the corn-grains ; and I find such a marked difference 

 between those of wheat, barley, and oats, that I cannot yet believe in 

 their mutual convertibility, until this has been established on more 

 satisfactory evidence. For it is a rule that has hitherto been found to 

 hold good most uniformly, that intimate structure is far more constant 

 than external form, and is a better test of affinities and differences : 

 e. g.y among all the varieties of apple, there is the same intimate struc- 

 ture ; so also among all the varieties of pear ; and these never approxi- 

 mate one another, notwithstanding the approximations in the appear- 

 ance, form, and flavour of these fruits." M S. Notes of a Physiologist. 



Brassica oleracea. 



