100 
THE COTTAGE GABBENER. 
December 10. 
I 
Mana' of onv rcailers have heard or read of the diffei-ence 
of opinion which exists respecting the true origin of 
that anomalotis production — tlie purple Ijahurninn, 
Cyt'mis Adami. Some hclieve it to be a cross-bred 
plant between the common Lahurnnm and the purple 
Ciitisus, while others as firmly assert that it must he the 
result of artificial treatment, although the facts respect¬ 
ing the process have escaped notice. 'J'ho question is, 
therefore, still at issue, no clue having hitherto been 
discovered to decide it cither way. Mr. Adam, in whoso 
nursery, near Vitry, in ]'’rance, it was originated about 
the year ]82.'i, lielievcd it to liave issued from a blind 
bud of the purple Cytisus inserted in the T.ahnrnum as 
a stock in the common way, as related in the Annals of 
tho Horticultural Society of Paris in 1830 by M. 
Poitean. A deputation from the Society was sent, after 
Mr. Adam’s death, to ascertain if the original plant was 
really a seedling or a budded plant. But the evidence 
of this deputation was contrary to that of Mr. Adam’s, 
and in favour of the cross-seedling side of the question. 
This gave currency to many wild and extravagant 
ideas on the continent as to tho effect of hybridisation. 
'J'he old notion, that mules can revert to one of their 
parents, was strongly urged by some, and this anoma¬ 
lous plant adduced as a strong evidence that mules 
could change in time to either of their parents. Even 
the exploded doctrine of superfoetation was revived lo 
account for the origin of such a plant; and to the 
present time no satisfactory answer can he given as to 
how, or by what means, the plant first originated, and 
it is altogether different from those variations called 
“ sports.” Our own belief inclines strongly to the arti¬ 
ficial mode through the blind bud, because, among other 
reasons, if it is really a cross-bred plant, it stands alone 
in its habits among the thousands that have been 
so produced. Both i^arents, very nearly in their ori¬ 
ginal characters, are produced sinudtaneously with the 
mixture between them ; and the sf^eds of the two 
parents, tluis produced, wilt come true in their gene¬ 
ration without any variation whatever. 
These facts of themselves amount almost to a proof 
that the purple Lahurnum is not a cross-bred plant, but 
bad its origin in some way which we have not yet dis¬ 
covered. For these peculiarities are widely different 
from the effects of hybridising on plants, as far as W'O 
have yet discovered them. We have not yet arrived at 
any conclusion which woidd indicate a law or rule by 
which the reversion of a true cross-bred plant to one or 
either of its parents is provided for; and, after experi¬ 
menting on tliis point for very many years, we cannot say 
that we ever forced a true cross to assume or re-produce 
either of its parents; and we believe the thing is an 
actual impossibility in the vegetable kingdom. It is true 
that many writers on this subject assert, that what they 
call a mule plant will in time revert to one of its 
parents; but no one wdio bas dived much into tho 
mysteries of hybridisation can countenance such a 
doctrine. All that our experiments on the subject have 
hitherto brought to liglit is our own total ignorance of 
any such law'. We cannot even, with any degree of 
confidence, foretell whether the offspring of any two 1 
jilants will be fertile or sterile. The most dissimilar , 
species in any genus, if they will cross at all, will be as 
likely to produce a fertile offspring as not, while two j 
others, to all appearance the nearest in aspect and ! 
affinity, will be equally likely to have a sterile offspring, i 
We make use of tho words fertile and sterile to get rid 
of the confusion caused by the different meanings 
given to the term mule by different w'riters. Professor 
I.indley, in his “Theory of Horticulture,” limits the use 
of the word mule to the oOspring of two distinct 
species, whether fertile or not; while he makes “ cross¬ 
breeding” to cover all the ju’oductions between distinct 
varieties; and if all writers had kept to these defini¬ 
tions we sliould be at no loss to comprehend their 
meaning; but Dr. Herbert, late Dean of Manchester, 
applied the terms hybrid, cross-bred, and mule, indis¬ 
criminately, and scouted the idea of jilacing any limits 
between species and permanent varieties; while other 
writers apjdy tho word mule to any cross that is sterile, 
and writers on cross-breeding in the animal kingdom 
are jnst as far at sea in their o])inions and terms. An ' 
actual impediment to a ])ro]ier understanding of the 
language of hybridisation is thus placed in our path, 
w'hich it would bo useful to remove by discarding the 
word mule altogether, or at least from our popular 
literature. 
On poor, light soil the colour of tho flowers of the 
purple Laburnum is much affected by the nature of the ' 
previous season. After a hot, dry summer the flowers 
are almost all of that dingy colour peculiar to the first 
variation, for a “sport” it can hardly he called; and 
after a wet, cold summer the j’ellow flowers of the 
Laburnum are in excess. Those variations are not so 
manifest when tho tree is growing in rich moist soil 
till it attains its full si/.e. If we could fathom tlie law ^ 
which governs these variations, it might form a step . 
towards the clearing of tho mystery which hangs over 
the real origin of the plant. 
Dr. Herbert suggested a very ingenious and probable 
hypothesis to account for the possible origin of this tree, 
which can easily be reconciled with the statement given 
by Mr. Adam, already referred to. Dr. Herbert believed 
that the shield of the ])urple Cytisus hud might be still 
alive after the bud' itself was destroyed, and that this 
live portion might unite with the Laburnum stock in 
tho absence of a bud, and that tho new wood, or cellular 
matter, which formed over the wound, between the 
shield and tho stock, might produce an incipient hud, in 
tho absence of a leading bud ; and if the new bud was 
from an intermixed matter formed by the two plants, it 
could hardly fail of partaking of the two natures—that 
is, of the I.aburnum stock and tho purple Cytisus bud, 
which, in reality, it does; and the question is, how ai-o 
we to proceed in order to obtain similar productions 
between other allied plants, for we must still adhere to 
the fact that species can oidy mix by pollen, or by this 
kind of union, wlieii they are nearly related to each 
other. If it is possible to force a hud from two wounds 
in nnion with each other, and partaking of the natures i 
