lx 
Development and Distribution of Vegetation. 47 
hair. The last is sometimes thought unnecessary, but we certainly cannot say 
that this organ is a transformed something else. Adopting these four parts as 
essentially distinct, it is usually an easy matter to refer everything else to one 
or the other of them. The so-called roots of mosses are hairs. The abundant 
clothing of all young roots are hairs, performing an exceedingly important 
service. The various grades of woolliness of stems and leaves and even of 
prickles and spines are hairs, often more or less modified. Leaves, besides 
serving as foliage, take great varieties of forms and offices,— notably as parts 
of flowers. Nothing can be better substantiated by observation than that 
each part of a flower, however unlike in appearance and function the original, 
is a modified leaf. The proofs are too well known to admit of discussion here, 
but an illustration may perhaps be permitted. 
We all know what an apple is—a rounded, solidified, spiced, sweetened 
and perfumed mixture of juice and substance, done up in a polished package 
delicately chromoed by the sun. This is our unuttered definition as we help 
ourselves to the best in the basket. Let us try to see what another definition 
may be, at the risk of spoiling some poetical notions which we do and should 
value as agreeable occupants of our minds. 
In an apple blossom it is easy to make out an inside series of green organs’ 
called sepals very similar in structure and appearance to small foliage leaves. 
There are five of them, separate above, united below into a short tube. Borne 
on these are five petals of a delicate pink and white color and larger size; 
next, also attached to upper end of the calyx tube, are numerous stamens and 
finally, in the center of the flower, five pistils with adhering ovaries but dis- 
tinct styles. Let us now examine the matured fruit. 
Starting with the idea that the apple must be a modification of some of the 
above-named fundamental parts of plants, let us endeavor to find out what. 
The stem of the fruit is woody with a thin layer of bark on the outside. The 
depression at the apical part of the apple contains what is often called the 
“eye’’. It has five pointed green appendages which any one may recognize 
as the tips of leaves. 
Let us now cut the apple in two at its equator, so as to leave one-half with 
the stem at its centre and the other half similarly bearing the eye. We first 
see five cavities arranged symmetrically, their pointed internal extremities 
approaching near to acommon centre. The lining of these cavities is cartila- 
ginous, much different from the pulpy texture of the fruit. Looking a little 
closer ten green points can be made out, arranged in a circle something like 
midway between the outer ends of the five cavities and the surface of the 
apple. Five of the green points are opposite the cavities and five alternate 
with them. If we slice off the apple parallel to the first cut, we find the green 
points are still seen, showing that they are really green lines running from 
stem to eye. By careful following, it may be made out that five of them run 
to the leaf points of the eye. Each evidently represents the midvein of this 
transformed leaf. These green dots are the alternating ones with the core cav- 
ities. It seems pretty certain therefore that the apple fruit has in its make-up 
at least five leaves, very much thickened and joined together into one mass, 
except at their tips. These leaves form the outside portion of the apple, their 
lower surfaces being outward and the lower epidermis changing into the skin 
of the fruit. 
On further study it is not difficult to satisfy one’s self that the five core-cav- 
ities are formed, in each case, by the folding of a leaf along the mid-rib, the 
two edges meeting at the centre of the fruit. The green spot is the mid-rib 
of this leaf; the cartilaginous lining of the cavity is the modified upper epi- 
dermis. The exterior portions of these thickened leaves are fused together 
among themselves and with the first five leaves we have described. We find 
then that an apple consists of ten leaves much modified and intimately joined 
