be the cafe with all the Silver Firs, that their feed feems to be productive only once in three or four years.
We believe that the experience of feedfmen will bear us out in faying that three out of four confignments of
feeds of thefe Firs, from one fource or other, proves a failure. Such was the experience of thefe gentlemen
with the Picea nobilis. It naturally became an object of fome intereft to know what was the infect which
occafioned this havoc. This was not difficult to afcertain. A cone placed in a clofed glafs veflel in due
time brought out hundreds of a fmall hymenopterous infect belonging to the genus Megafligmus, and now
named Megafligmus Pini, allied to the Chalcidites (fmall Ichneumon flies), of which the woodcut [fig. 19]
is a highly magnified reprefentation. The fort of calyx out of which the abdomen fprings is peculiar to the
tribe of infects to which this fpecies belongs. Thefe flies are generally fuppofed to be entirely parafitical;
but the fact of immenfe numbers coming out of the cones without any admixture of other infects, and
from no trace of the (kin of the facrificed larva being to be found in any of the empty kernels from which
the infect emerges, this would feem to be unlikely, fo far at lealt as regards this fpecies, as it is highly
improbable that all the larvie could have been ichneumonifed. It thus appears
reafonable to fuppofe that the infect which lays its egg in the feed is the Mega-
Jtigmtts which afterwards appears; and it follows as a corollary that it is
(imply a vegetable feeder, and that the whole of the fpecies, of the family of
Ichneumonidfe, are not parafites. Similar exceptions to the general economy
of a family have been found in other groups. The converfe of what
takes place here has been found in the Cynipidce or gall-flies, which live in
gall-nuts or morbid excrefcences caufed by their own prefence in the leaves
of oaks or other plants. Some of thefe have been fatisfactorily fhewn to be
parafitic in other infects. Subfequently to Murray and Beardfley's expeditions,
various importations have taken place, chiefly from the collections of Mr
Lobb or Mr Bridges, two affiduous collectors, who have done much to fupply this country with the
cream of Californian vegetable productions. The fame drawback which attended previous efforts has
accompanied theirs: the feed is feldom free from the attacks of the Megajligmus Pini; and when one is
found in a cone, it is fafe to affume that fcarcely a fingle productive feed will be found in it. The careful
and affiduous mother leaves not a found feed unfupplied with an egg ; nor does (lie wafte one upon a feeble
or unproductive embryo. Seedlings of this tree, therefore, (till are, and are likely to continue, fcarce and
valuable.
Properties and U/es.—For decoration no tree can be finer; but fo far as we yet know, its ufes go no
further. Its timber was (tated by Douglas to be of excellent quality. This is now known to be a miftake.
It is white, foft, and nearly worthlefs.
Culture.—No particular mode of cultivation is required for it. It is very hardy, having paffed through
the winter of 1860-61 unfcathed. There appears, therefore, no reafon for the precaution which is ufually
taken of fowing the feeds in a cold frame; a precaution, no doubt, taken by cultivators more out of
regard to the high price and value of the feed than from any neceffity or fpecialty in its growth. We are
not aware how it thrives in undrained wet foil. The common Picea peclinata likes a good deal of moifture,
and we fhould not be furprifed that P. nobilis had fimiliar predilections; but we have never feen it growing
in fuch conditions. It is generally placed in fome fpecially well-drained fpot near the manfion, where it can
be readily reached, and feen, and admired. It feems, however, to thrive well everywhere, and is now pretty
generally diftributcd in this country.
The plants raifed from home-grown feeds are not fo (trong and healthy as plants grown from feeds
brought from their native country; and it has been obferved that a large proportion of the fcedlings from
home-grown feeds foon become difeafed, the leaves firft decaying at the tips and gradually becoming wholly
dead [figs. 20 and 21]. The tips of the leaves firft (hew it; they begin to wither, and gradually the decay
fpreads
fpreads until the whole plant has a rufty appearance, fo that we have heard it fpoken of as a ru(t attacking
the plant. It is not fo, however; it is merely the ends of the leaves becoming brown by ^
decay, and dropping off by mortification like a froft-bitten toe, and doubtlefs from the '1-*
fame caufe, viz., defective circulation: how caufed is another queftion. This has been )|" |
attempted to be accounted for in two ways: firft, by affuming that the feeds have been j' 1 •;!/ gjffiSjSjf
what is called " imperfectly impregnated;" or, fecond, by fuppofing that they have been j
fertilifed by the pollen of the common Silver Fir growing in company with the P. 1
tiobilis—in fhort, by fuppofing the young plants to be hybrids. As to the firft idea, we F'8'
fcarcely know enough of the fecrets of the alembic of nature to be able to fay whether fuch a thing as
" imperfect impregnation " can or does exift; but we can undcrftand (what is probably meant by the phrafe)
that, as in ordinary cafes, fome ovules arrive at perfection, and others do not; thofe which do, have had
the energies of the plant mainly directed to them, and the others which do not, have had a lefs (hare of fuch
vital influence. So, in a plant placed in uncongenial circumftances, the energies directed to the ovules may
never be fufficient to give them their full (hare of vitality, and hence may produce plants of a weakly conftitution,
and the refult be fomething, perhaps, refembling in nature the difference between a home-born
Englifhman and one born in America or Auftralia of Englifh parents. This decay has hitherto been
remarked only in plants produced from home-grown feed, and has been obferved in them even when grown
under .exactly the fame conditions as plants raifed from feed of foreign growth, and it has hence been fuppofed
to be congenital; but it would appear that this is not the cafe; for during the wet feafons of 1861 and
1862, we have had old grafted plants fuffer in their leaves in precifely the fame manner. It may, however, be
objected to this exception, that grafted plants are liable to the fame fufpicion of weaknefs as home-grown
feed, being like them produced in an abnormal manner, or at leaft under circumftances different from thofe
provided for them by nature. Regarding the fecond theory of the difeafe—viz., that the feedlings from
home-grown feeds are hybrids—it may be mentioned that the difeafe, fo far as yet afcertaincd, firft (hewed
itfelf in plants produced from feeds grown at Elvafton, thefe being the firft feeds produced in this country.
This gave rife to an unfounded report that, when the trees at Elvafton began to bear cones, Mr Barron,
under whofe able charge the plantations were, finding no male cones, fupplied their abfence by dufting them
with a branch of Silver Fir well charged with male catkins. The beft refutation of this report is, that the
difeafe alfo appears in nurferies where home-grown feed not procured from Elvafton has been ufed. The
following remarks on the fubject, underftood to be from the pen of the Rev. M. J. Berkeley, one of the ableft
vegetable phyfiologifts in Britain, appeared in the "Gardeners' Chronicle," Jan. 18, 1862: " A moft extraordinary
cafe of bad conftitution in home-produced feedlings of Abies nobilis has lately been fent to us by
Mr Murray from the Royal Horticultural Society. A confiderable portion of plants raifed from homeripened
feed are affected by a peculiar chlorofis, at firft confined to the tips of the leaves, but gradually
increafing downwards and ultimately caufing death, when they are attacked by a minute fpecies of Phoma,
which is, however, an after-growth, and not the primary caufe of evil. The condition of the buds, indeed,
apparently refembles that which occurs in the common Silver Fir, when affected by the fungus that
caufes the Witches' Befoms (Hexen-befen) which are fo common in the German forefts, and which
occafionally make their appearance in this country. But there is no identity of caufe, nor, as in that
cafe, does the chlorofis extend when the buds expand through the whole length of the leaf. The cafe
appears to us decidedly to be one of conftitutional weaknefs arifing from propagation in a climate where
the conditions arc fuch as arc not favourable to perfect development; and it is probable that feedlings
from thefe difeafed plants, fhould they ever have vigour enough to bear fruit, will have the evil in an
aggravated form. We have ourfelves proved, in the cafe of annuals, that where the parent plant is
chlorotic, the produce is liable to a fimilar condition year after year, and there is no reafon why the fame
condition fhould not hold good in plants of longer duration. It is evident that in fuch a cafe there
is no remedy. Original weaknefs of conftitution may admit, under fcientific treatment, of palliation, but
a found and healthy ftock will fcarcely ever be derived, except poffibly by croffing, from one which is
originally weak, or deficient in the conditions effential to health."
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