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external to it being more or less accessory. The above may be considered the first stage of developement, when
the pericarp and albumen have fallen away; the outer coat of the radicle is expanded into a horizontal membrane,
firmly attached to the cuticle of the Fagua, and the cushion-shaped body is pressed against the stem or twig of the
tree, at that point where the process of penetrating the integuments will begin.
The second period commences by the cusliion destroying the cuticle beneath it and reaching the e])iphlceum.
StUl pushing onwards, it raises the membranous expansion and causes the siuTOimding cuticle, with or without
some of the subjacent tissue, to be also detached with this membrane, for a considerable distance roimd the base
of the radicle. The lesion to the plant is now extensive, and a diseased action, favom-able to the progi-ess of the
parasite is induced, for the whole bark opposite the Myzodendron is raised from the wood (P late CYI. f . 8).
The cushion, which may now be called a true root, is protruded rapidly, and the disorganization of the tissues
it meets in its progress is equally rapid, a cavity is foi-med in the bark and the edges of the flesliy sheath that sm-rounds
the root commence generally to form a close adhesion with the lips of the wound, (Plate CVI. / . 10 and 11).
At last the root, having penetrated the bark, an-ives at the space left between the latter and the wood (P late
CVI. f . 9), and, from the perpendicular direction, assumes a horizontal one. Previous to this there has been a
deposition of much disorganized cellular tissue between the bark and the wood. The spiral vessels that descend
from the plumule have followed the course of the root, which has gained the point where an abundance of
nutritive matter is retained by the disorganized cellular tissue, and where a further supply is ensured for the use of
the now fuUy established Myzodendron.
If at this time, the end of the second period, a vertical section of the Myzodendron and Fagus together be
made, the appearance will be that represented at Plate CV I./. 10, where the plumule is seen fully developed into
two opposite leaves, ready for protrusion, and where also a large space is left that almost isolates the axis of the
caulicule from what remains as an investing membrane. The true root, or cushion-shaped body, at no time
appears to form an adhesion with the bark; that being effected by the thick and fleshy sheath thi-ough which the
radicle is protruded.
The union between the sheath and bark is more or less complete in different specimens that I have examined,
according to their stage of growth. At Plate CV I./. 9, though the radicle has pierced the bai-k, the sheath
had hardly united with the edges of the wound, and the young Myzodendron was removed witliout force from the
Fagus; at / . 10 the union is complete, probably from the stem of the Beech being younger, and affording less
resistance to the attack, and lastly, / . 1 1 represents a still more close union, the circiunference of the sheath
passing along the inner walls of the bark and its revolute edges, thus completely enveloping all the diseased part.
The third period is marked by the exsertion of the plumule from a dehiscence of the two coherent cotyledons,
the consequent elongation of the ascending axis or stem of the Myzodendron, the deposition of the liber and
scalariform tissues in their proper positions; a process I have never had the opportunity of following.
A branch attacked by the Myzodendron suffers no apparent change below their point of union, but all beyond it
being insufficiently nourished, does not increase in proportion, and after a time dies from atrophy. The whole juices
of the branch being suddenly arrested at its abrupt termination, this dilates into the fom of a cup, which, from the
turning of the Myzodendron towards the light assumes an erect position. This cup (Plate CV I./. 12) is more or
less broad (sometimes three inches in diameter) and shallow, uniformly covered with cuticle and bark, and has
infiexed, wrinkled edges. On a vertical section (Plate CVII. / . 1) it is seen to present a shallow, conical hollow,
in which the Myzodendron rests, and to be formed of as many layers of wood as years have elapsed since the
germination of the parasite. The equally expanded base of the latter completely fills this cup in the fom of a
disk, whose edges overlap those of its support, and swell out into a prominent ridge at their point of union. At
Plate CVII. / . 1, a vertical section of the cup of the Beech and still attached discifom base of the Myzodendron
is given. The union of the cellular tissues of the bark of the two is very intimate, but in no case and no stage of
their growth have I been enabled to trace any interlacing of their tissues, or any union of the one -with tlie other.
The woody plates o fth e various branches oi &<s Myzodendron aU meet in its expanded base, and are there strangely
convoluted and contorted, enclosing masses of brown and dead cellnlar tissue, probably consisting m part of the
alburnum of the bccch deposited there, as well as of the decayed meduBary rays of the Myzodendrm. Lower
down, the woody plates, much reduced in size, slightly converge and meet the layers of wood of the beech ; these
may perhaps come into actual contact, but generaUy, if not always, there is a deposit of disintegrated cellular
tissue between them. The Myzodendrm, having finally arrived at its fuU gi-owth, a time probably coincident with,
if not dependent upon, the period when the Fagm cannot supply it with sufficient nutriment, faUs away and leaves a
cup stm attached to, or rather terminating the branch of a Beech (P late CVI, / , 13) whose mner surface is
channelled with radiating fissures and these again crossed by the concentric rings of the wood.
This process of germination is probably similar to what is pursued by many Loranthaceous plants, aud is
rudely represented by M, Korthals,* as occurring in some Javanese species of this Order.
The resemblance between the sheathed radicle of LorantJm and Vkoum and a coleorhiza was first pointed out
by Mirbelt, but hardly admits of a strict comparison of tins order with FndorUzex in tbis respect, any more than
the confernimiuated cotyledons of this species are to be compared with the one large cotyledon of the true Mono-
cotyledones, for in rkeum. the cotyledons equaUy enclose a cavity containing the plumule, though they are not
combined. Tbe sheath of the root of lorantliaceee appears a peculiar organ, especiaUy adapted to the wants ot the
plants in wbicli it occurs.
So very highly organized a nature of the embryo renders it probable that germination takes place very soon
after the faU of the seed, or perhaps even before. I t is remarkable too, that tbe operation proceeds in summer
and exposed to the fuU light of day, there being no viscous substance to protect the cmbi-j'o. I have described
the radicle as descending from tbe seed to its future point of attachment, but here, as in Fkcum, it is immaterial
to which sm-face of tbe branch the embryo is approximated, the radicular extremity being invariably directed
towards the axis. In a dried specimen of M. qnadrifiorum I have found a seedling plant fidly estabUshed on its parent.
The frequent curving of the cauUcnle also, immediately after the protrusion of the radicle, is highly curious, the seed
being loosely suspended by its filamentous appendages, and thus presenting no fulcrum or point of resistance, in
attempting to overcome which, such a ftexiire might be induced. It is worthy of remark that both these functions,
so closely resembling instinct in the lower animals, are characteristic of an embryo of more complex structure
than any with which I am. acquainted..
The absorption of nourishment from the albumen takes place through the cotylcdonary extremity, which is
retained in the perispenn, and by the time the radicle has gained the bai'k of the tree, the fécula of the albumen
is wholly absorbed. This transfer of nourishment to such an extent, effected simply by the contact of two
cellular membranes, only one of them being endowed with life, is a proof that in vegetables no verj° highly com-
pbcated tissues are required to conduct a very subtile chemical operation.
The bark of the Beech becomes detached from the subjacent wood prior to its complete penetration by the
Myzodendron; the intrusion itself is by no means a mechauicEil operation, there can be little or no pressiu-e exerted
by an embryo suspended as this is, it must be effected by the coiTOsiou of the cortex which simultaneously
produces a separation of the bark from the wood, materially facibtating the progress of the radicle.
I have mentioned that the duration or period of life abowed to the Myzodendron, is probably determined in
some degree, by the effect it produces on the plant it infests; the latter being of slower growth, is sure at some
period to.rid itself of the intruder. Thus, the weight of the parasite being considerable, and exerted upon the branches
* Verhandebug over de op Java &c. verzamelde Loranthaceæ door P. W. Korthals.
j- Annales du Muséum d’Hist, Nat. vol. 16. p. 429. t. 21.
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