The Virginia enterprise. [volume] (Virginia, St. Louis County, Minn.) 1893-19??, 1905-06-23


union is generally understood to deter
mine the whole success or failure of the
graft. These phrases, good unions and
poor unions, are common in horticulture,
yet their significance is generally I'M
known. The facts are often wrongly
ter at times essentially misunderstood.
1t is pointed out by Prof. Waugh that
in herbaceous grating (where soft
growing parts are used) there is no gen.
eral commingling of the cells of scion
and stock as has been popularity mag
ined. The original scion and the origin
al stock remain to- the end of their ex
istence very largely separate and dis
tinct. Disregarding for moment the
very thin cambium zone, the stock and
scion are made up wholly of dead wood
and bark. With perfectly negligible ex-
:eptions the cells are all dead, totally
and forever. 1t is absolutely impossible
for them to grow or to unite with any
thing. One might as we'll talk of max
ing lead pencil unite with penholder
or neckyoke with a singletree. The
two may be glued together, waxed to-
gether, tied together, but they can never
unite.
The thin sheet of cambium, lying be-
tween the bark and the wood, is the only
portion of the tree stem which is really
alive, the only portion which can grow
and is therefore the part where we must
look for the beginning Of the graft union.
Note Fig. l, which is a diagram of cleft
graft three years old. The black por-
tions represent the wood of the original
scion and stock; the white portions
three annual layers Of wood which have
grown since the graft was made
1t has long been the dream of gar
deners to produce new kinds of plants
by the graft union of new scions and
stocks. Our present observations show
this to be impossible. No matter how
closely the two kinds of cells may lie
against one another, their contents are
never mingled in the production of the
cell. The cell tissues of the stock and
scion may commingle or lap in together
somewhat = the line of union, but this
mixture is only mechanical, not physio-
logical. The experiments were con-
Quoted with bud unions, and from our
view there is no difference between e.
bud graft and long scion graft.
Fig. 2 shows diagramatically the
growth of bud when set upon a stock.
The black portion represents the wood
OF the stock, the shaded portion the bud
or scion and the white portion three an
nual layers Of growth which have been
put on since the bud was set. In this
case, as with the common graft, the lay
ers OF the new growth are continuous,
running from top to bottom without any
break at the plane of junction.
II the normal union of scion and stock
IL made of such complete and continuous
cylinders of annual growth as above
| mentioned, one will naturally ask the
reasons for the unsuccessful unions. The
answer is not an altogether easy one.
We may approach it by saying thai,
when the two members are unlike in ma
ture and In some way physiologically in
compatible, the wood does not heal read
lily, owing to some sort Of irrigation
| which continues to be felt at this point.
After close study of large number
of defective scions, Prof. Waugh has
reached the opinion that they are al
most always due to this incompatibility
| OF stock and scion.
1t is a common notion among horti-
culturists that careless or ignorant mau-
ipulation in the grating will lead to
poor unions. There seems to be little
ground for this opinion. If the stock and
scion are of varieties which are congen-
ial. and if the graft or bud grows at all.
the union will nearly always be good.
Poor manipulation will often cause the
failure OF large percentage to grow,
but it seldom affects permanently the
strength of the union in those crafts
which live at all. This interesting bulle-
tin covering these facts in detail is now
+; ready for distribution.