Every year when the boughs of a plant [or tree] have made an end of
maturing their growth, they will have made, when put together, a
thickness equal to that of the main stem; and at every stage of its
ramification you will find the thickness of the said main stem; as:
_i k_, _g h_, _e f_, _c d_, _a b_, will always be equal to each
other; unless the tree is pollard--if so the rule does not hold
good.

All the branches have a direction which tends to the centre of the
tree _m_.

[Footnote: The two sketches of leafless trees one above another on
the left hand side of Pl. XXVII, No. 1, belong to this passage.]

396.

If the plant n grows to the thickness shown at m, its branches will
correspond [in thickness] to the junction a b in consequence of the
growth inside as well as outside.

The branches of trees or plants have a twist wherever a minor branch
is given off; and this giving off the branch forms a fork; this said
fork occurs between two angles of which the largest will be that
which is on the side of the larger branch, and in proportion, unless
accident has spoilt it.

[Footnote: The sketches illustrating this are on the right hand side
of PI. XXVII, No. I, and the text is also given there in facsimile.]

397.

There is no boss on branches which has not been produced by some
branch which has failed.

The lower shoots on the branches of trees grow more than the upper
ones and this occurs only because the sap that nourishes them, being
heavy, tends downwards more than upwards; and again, because those
[branches] which grow downwards turn away from the shade which
exists towards the centre of the plant. The older the branches are,
the greater is the difference between their upper and their lower
shoots and in those dating from the same year or epoch.

[Footnote: The sketch accompanying this in the MS. is so effaced
that an exact reproduction was impossible.]

398.

OF THE SCARS ON TREES.

The scars on trees grow to a greater thickness than is required by
the sap of the limb which nourishes them.

399.

The plant which gives out the smallest ramifications will preserve
the straightest line in the course of its growth.

[Footnote: This passage is illustrated by two partly effaced
sketches. One of these closely resembles the lower one given under
No. 408, the other also represents short closely set boughs on an
upright trunk.]

400.

OF THE RAMIFICATION.

The beginning of the ramification [the shoot] always has the central
line [axis] of its thickness directed to the central line [axis] of
the plant itself.

401.

In starting from the main stem the branches always form a base with
a prominence as is shown at _a b c d_.

402.

WHY, VERY FREQUENTLY, TIMBER HAS VEINS THAT ARE NOT STRAIGHT.

When the branches which grow the second year above the branch of the
preceding year, are not of equal thickness above the antecedent
branches, but are on one side, then the vigour of the lower branch
is diverted to nourish the one above it, although it may be somewhat
on one side.

But if the ramifications are equal in their growth, the veins of the
main stem will be straight [parallel] and equidistant at every
degree of the height of the plant.

Wherefore, O Painter! you, who do not know these laws! in order to
escape the blame of those who understand them, it will be well that
you should represent every thing from nature, and not despise such
study as those do who work [only] for money.

The direction of growth (403-407).

403.

OF THE RAMIFICATIONS OF PLANTS.



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