Part I of the _Nuovo Giornale Botanico Italiano_, by Prof. G.
UZIELLI (Florence 1869, Vol. I). He remarks as to the 'four modes':
"_Leonardo, come si vede nelle linie sententi da solo tre esempli.
Questa ed altre inessattezze fanno desiderare, sia esaminato di
nuovo il manoscritto Vaticano_". This has since been done by D.
KNAPP of Tubingen, and his accurate copy has been published by H.
LUDWIG, the painter. The passage in question occurs in his edition
as No. 833; and there also the drawings are wanting. The space for
them has been left vacant, but in the Vatican copy '_niente_' has
been written on the margin; and in it, as well as in LUDWIG'S and
MANZI'S edition, the text is mutilated.] four modes of growing one
above another. The first, which is the most general, is that the
sixth always originates over the sixth below [Footnote 8: _la sesta
di sotto. "Disposizione 2/5 o 1/5. Leonardo osservo probabilmente
soltanto la prima"_ (UZIELLl).]; the second is that two third ones
above are over the two third ones below [Footnote 10: _terze di
sotto: "Intende qui senza dubbio parlare di foglie decussate, in cui
il terzo verticello e nel piano del primo"_ (UZIELLI).]; and the
third way is that the third above is over the third below [Footnote
11: 3a _di sotto: "Disposizione 1/2"_ (UZIELLI).].
[Footnote: See the four sketches on the upper portion of the page
reproduced as fig. 2 on P1. XXVII.]
413.
A DESCRIPTION OF THE ELM.
The ramification of the elm has the largest branch at the top. The
first and the last but one are smaller, when the main trunk is
straight.
The space between the insertion of one leaf to the rest is half the
extreme length of the leaf or somewhat less, for the leaves are at
an interval which is about the 3rd of the width of the leaf.
The elm has more leaves near the top of the boughs than at the base;
and the broad [surface] of the leaves varies little as to [angle
and] aspect.
[Footnote: See Pl. XXVII, No. 3. Above the sketch and close under
the number of the page is the word '_olmo_' (elm).]
414.
In the walnut tree the leaves which are distributed on the shoots of
this year are further apart from each other and more numerous in
proportion as the branch from which this shoot springs is a young
one. And they are inserted more closely and less in number when the
shoot that bears them springs from an old branch. Its fruits are
borne at the ends of the shoots. And its largest boughs are the
lowest on the boughs they spring from. And this arises from the
weight of its sap which is more apt to descend than to rise, and
consequently the branches which spring from them and rise towards
the sky are small and slender [20]; and when the shoot turns towards
the sky its leaves spread out from it [at an angle] with an equal
distribution of their tips; and if the shoot turns to the horizon
the leaves lie flat; and this arises from the fact that leaves
without exception, turn their underside to the earth [29].
The shoots are smaller in proportion as they spring nearer to the
base of the bough they spring from.
[Footnote: See the two sketches on Pl XXVII, No. 4. The second
refers to the passage lines 20-30.]
415.
OF THE INSERTION OF THE LEAVES ON THE BRANCHES.
The thickness of a branch never diminishes within the space between
one leaf and the next excepting by so much as the thickness of the
bud which is above the leaf and this thickness is taken off from the
branch above [the node] as far as the next leaf.
Nature has so placed the leaves of the latest shoots of many plants
that the sixth leaf is always above the first, and so on in
succession, if the rule is not [accidentally] interfered with; and
this occurs for two useful ends in the plant: First that as the
shoot and the fruit of the following year spring from the bud or eye
which lies above and in close contact with the insertion of the leaf
[in the axil], the water which falls upon the shoot can run down to
nourish the bud, by the drop being caught in the hollow [axil] at
the insertion of the leaf. And the second advantage is, that as
these shoots develop in the following year one will not cover the
next below, since the 5 come forth on five different sides; and the
sixth which is above the first is at some distance.
416.
OF THE RAMIFICATIONS OF TREES AND THEIR FOLIAGE.
The ramifications of any tree, such as the elm, are wide and slender
after the manner of a hand with spread fingers, foreshortened. And
these are seen in the distribution [thus]: the lower portions are
seen from above; and those that are above are seen from below; and
those in the middle, some from below and some from above. The upper