On the Reproduction of Plants. 267 



leaves; from this bud after elongation, other leaf-buds are often 

 developed, each consisting like the first of a number of leaves. 

 It is an admitted fact (as may be found in Treatises on Vege- 

 table Physiology), that each of these buds is a proper plant- 

 individual, and that those constituting a tree are as distinct 

 and independent as the several polyps of a compound zoo- 

 phyte ; and that the tree therefore is as much a compound 

 group of individuals, as the zoophyte. In some cases the 

 plant forms but a single leaf-bud ; in others, where there is 

 successive germination for. a period, the number is gradually 

 multiplied, and more or less according to the habit of the 

 species. So among polyps, there are the simple and compound 

 Tubularia, Campanularia, and the like. 



After the plant has sufficiently matured by the production 

 and growth of its number of leaf-buds, there is a new deve- 

 lopment — a flower-bud — consisting of the same elements as 

 the leaf-bud, but wholly unlike it in general appearance — 

 as much so, as the Medusa is unlike the polyp. The flower 

 individual starts as a bulb from the leaf individual, or the 

 group of leaf individuals, and is analogous in every respect 

 to the bulbs from the Campanulariae and allied species ; and 

 when it has fully matured, it produces, like the Medusa, 

 ovules, or seed — these seed to begin the round again of suc- 

 cessive or alternating developments. 



Thus among plants the seed produce leaf individuals ; and 

 these produce seeds ; precisely, as the egg produces polyps, 

 the polyps bulbs, that develop into Medusae, and the Medusae 



When we follow out this subject minutely, we find the 

 analogy completely sustained even in minor points of struc- 

 ture and growth. The leaf-bud consists of leaves developed 

 in a spiral order ; and in the polyp, as some species show be- 

 yond doubt, the tentacles and corresponding parts are spiral 

 in development. The same spiral character is found in the 

 flower, but the volutions are so close as not to be distinguished 

 readily from circles. In the Medusae referred to, the regu- 

 larly circular form is far more neatly and perfectly developed 

 than among the polyps — as is clearly seen in a comparison of 

 the polyp Coryna, with the elegant Sarsia, a species of which 

 is described and beautifully delineated in Professor Agassiz's 



