GOETHE ON THE METAMORPHOSIS OF PLANTS. 331 
differ most from the cotyledons in being flat and of a delicate texture, 
and especially in being formed like true: leaves, in being perfectly 
green, and in being situated on a visible node. = Their connection with 
the future stem-leaves can no longer be denied; they are neverthe- 
less inferior to them in the imperfect state of their margin. 
20. At each successive node the form of the leaf attains greater per- 
fection; the midrib lengthens, and the side-ribs, which arise from it, 
extend more or less towards the margin, The different relations of the ` 
ribs to each other are the principal cause of the various shapes we ob- 
setve in leaves,* which are notched, deeply incised, or formed of many 
leaflets, looking like little branches. The Date Palm is a striking instanee 
of the most simple form of leaf becoming gradually but deeply di- 
i As the leaves succeed each other, the midrib lengthens, till at 
last it tears asunder the numerous compartments of the simple leaf, 
and an extremely compound, branch-like leaf is formed. 
21. The development of the leaf-stalk keeps pace with that of the 
leaf; the stalk being either closely cohereut with the leaf, or so formed 
as ultimately to be easily severed from it. 
22. We see in different kinds of plants that this independent leaf- 
stalk has a tendency to assume the form of a leaf, as in the Orange ; 
its structure, which for the present we pass over, will afford us matter 
for future consideration. $ 
23. Neither can we now enter upon a closer examination of the 
stipules; we can only remark in passing that, especially in those 1n- 
stanees where they constitute a part of the leaf-stalk,$ they share 1ts 
future transformations in a remarkable manner. 
724. Whilst the leaves principally derive their first nourishment from 
the more or less modified fluids which they draw from the stem, it is to 
: istribu- 
n observers hold that the mode of distri 
tion of the ribs of the leaf. depends essentially on the form of the latter. De Can- 
er of the å p : of 
"t Tréeul describes the leaf of the Date Palm as a compound - o tnt fat 
Whieh are attached by their points to a cellulo-fibrous cord, - jj aapi ag 
: leaf. . By the rupture o is cord, and by the peeling ,m - 
brownish pellicle, which at first covers the w ole | 
Feuill rom each other. oru Mém 
: es, Ann. des Se, Nat. 3rd ser. vol. xx. p. 499-7. 3 i 
"t As illustrations may be cited the phyllodia, ot ilated foliaceous petioles of some 
Species of Acacia, Oxalis, etc. i a 
"8 For a concise account of the different kinds o 
in stipules, see Griffith, Notulee, 
Vol. i. p. 233, 
E 
x 
