The death of trees does not appear to ai-ise from any natural period being assigned to the existence 
of their living tissues, or reproductive powers. When the tissues of a tree are very old they lose their 
vitality, especially in the centre of the ti'unks of the trees ; and, on being exposed to the atmosphere, or 
moistm-e, they readily decay. The process of new growth is sometimes more rapid than tliis decay, and 
thus trees exist with enormous cavities ih their interior. The time, however, comes, sooner or later, 
when a separation takes place between the roots and branches, and then the tree ceases to exist, al- 
though the tissue that has been conveyed away from it, in the form of slips and grafts, may still con- 
tinue to flourish. Thus, the old stump of the Ribstone Pippin Apple is but struggling for life in Ribstone 
Pai'k, while the slips from its branches adorn a thousand orchards, and supply the thousands upon 
thousands of bushels of Ribstone Pippin Apples that are annually consumed. 
6cci cdccZe 
1 d c d cd c i 
HOMZOXr.iL OR TRANSV^RSK, A^Ii PIlUrE.XDlCULyXJl 
SECTION, OF THE STEM OF AN EXOGEN OF THEKE YE^VRS' 
GROWTH, In the centi-e of ench is seen the pith, 
a, composed of cellular tissue; sm-rounding: it is the 
medullai-y sheath, b ; and exterior to it are three rings 
of wood, each consisting: of c, c, dotted dncts, and dy d, 
woody fibre. The last-formed is in contact with the 
bark, e, e, inwliieh the layers are Indistinct. — Carpetitei-^ s 
Vegetable Physiology. 
Horizontal and vERTicAt, s ction of the s em 
OF AN Endogen, showing the bundles of ducii, 
woody fibre, and spiral vessels, irresyularly disposed 
through the whole stem, a, n, portions of cellular 
tissue ; 6, b, spiral vessels ; c, c, dotted dnets ; d, rf, 
woody fibre. The cellular portion of the sldn, which 
i n ]£xogcns is separated by the first introduction of wood 
into pith and bark, here remains permanently inter- 
mingled -nith it. 
[The accompanying- engra\Tngs, representing Sections of Exogen and Endogen, will explain them- 
selves. The number of zones in trees will probably give a tolerable approximation to the years of 
gi'owth in temperate climates ; but even here, two may be formed in one year, if any great check of 
the growth suddenly occurs during the Simimer. In tropical climates the indication is far more doubt- 
ful ; Adanson's computation, made in this way, carried the age of the Baobabs to from 5,000 to 6,000 
years. It has been stated that montlily rings are formed in the tropics of South America {Hopkins' 
Researches in Magnetism). Some plants, such as the Cacti and Cycadeoe, reqviire more than one year 
for the formation of a zone of wood. — A,H.] 
THE CULTIVATION OF PRIZE PELARGONIUMS. 
By Mr. JOHN PAEKEE, Gakdener to .T. H. Oughton, Esa., Elm Grove, Roehampton. 
fHE cultivation of prize Pelargoniums ha-^dng been a favourite hobby of mine for some years, and 
my labom's having been crowned with some little success, a few remarks on my mode of procedure 
may not be wholly without interest to some of the readers of the Gardeners' Mayazine of Botany. 
I do not know that my system of culture differs very materially ft'om that practised by others, but 
as it has always been attended with unfailing success, I am wilhng to hope that those who may 
follow my directions may not be less successful. The Pelargonium, or, as it is more generally termed, 
the Geranimn, is a favourite plant with most people, being admu-ably adapted for decorative piu'poses, 
in the conservatory and drawing-room as well as at public exhibitions, while by providing a regulai' 
succession of plants, and preparing them properly, a supply of flowers may be obtained, and that wth 
comparatively little trouble, thi-oughout the year. My object, however, in tliis article, is to detaU my 
system of management for exhibition ; the subject of their growth, for general decorative piu-poses, 
more especially in the winter season, may probably form another paper. 
To begin, however, at the beginning. The cuttings should be taken oif when the wood has been 
tolerably ripened by exposure to full light and air, and being prepared, should be struck under the 
