158 BOTANICAL GAZETTE [SEPTEMBER 
a plant there is no sharp line separating its embryonal from its 
subsequent life, and in the study of the development of the 
individual in order to make out the course of development of 
the species, we must follow its whole life from its beginning to 
its maturity. The leaves of dicotyledons present an interesting 
study from this standpoint. It is a well-known fact, as pointed 
out by Lubbock,’ that the earlier leaves are generally quite dif- 
ferent from the later. In the young plant of the field buttercup 
of Europe (Ranunculus arvensis), for example, the leaves of the 
first node (cotyledons) are obovate or slightly spatulate; the 
second leaf, round-cuneate and five-toothed; the third, broadly 
obovate-cuneate with five large teeth; the fourth, three-parted, 
the divisions cuneate and three-toothed; the fifth, three-parted, 
the divisions cuneate, narrower below and four to five-toothed 
above; the sixth, three-parted, the terminal division irregularly 
three-lobed, the lateral divisions deeply two-parted, all the sub- 
divisions toothed; the seventh, three-parted, the terminal divi- 
sion again three-parted, the lateral divisions two-parted, all the 
subdivisions narrow and more or less deeply and narrowly 
lobed. Here the earlier leaves suggest the mature foliage of 
Ranunculus abortivus, R. pygmaeus, R. pedatifidus, R. pusillus, R. 
hyperboreus, and others. It does not require much study to con- 
vince one, after an examination of Lubbock’s descriptions, that 
the young plants of different species of Ranunculus are much 
more alike than are the mature plants. And it is a familiar fact 
to those who have watched the growth of seedlings of all kinds 
that in general they resemble one another most when youngest, 
and that this resemblance becomes less and less as the plants 
become older. For many seedlings one can do no more when 
they first appear than to recognize the sub-class to which they 
belong; a little later the family characteristics may be made out, 
still later the genus is recognized; while it often happens that 
we must wait for the flower or even the fruit before we are able 
to certainly recognize the species. Sow seeds of a buttercup 
(Ranunculus), a clematis (Clematis), a potentilla (Potentilla), 
® On seedlings 2, 75, e¢ seg. 1892. 
