164 
THE GARDENING WORLD. 
February 25. 1905. 
lower organisms to form a cell wall merely as a protective 
covering. Many of these forms are microscopic in size, 
and their presence can only be detected by the naked eye 
when they exist, perhaps in millions, on the surface of water, 
giving that some peculiar hue according to the kind of 
organism. 
Needless to say, these delicate organisms can only exist in 
water or damp places, for if dried up they have to assume 
the form of a spore so as to withstand the dryness of the 
conditions until circumstances favour a resumption of growth. 
Some of these organisms live singly and in the_ active 
stages of life are endowed with means of locomotion by 
which they can move about in the water. Others again, 
such as theVolvox, live in colonies, immense numbers of 
them forming a globular ball with cilia projecting into the 
water like oars from a boat, the combined action of which 
causes the whole colony to roll through the water. 
From the simpler organisms, consisting of a single cell 
with or without a wall, the authors carry the story to higher 
and higher organisms, showing into what complex forms a 
single cell may develop in different genera and species. 
The history”of these cells becomes more interesting as we 
turn to the higher plants, some of which are built up of cells 
or units of remarkable form. In the common Bean, as well 
as in the common Rush, the individual cells form a star 
united to one another by the ends of the rays only. It must 
be understood that in these higher plants the cells are usually 
more or less completely united,and that, too,permanently. The 
cells that go to form the giant Sequoias of California are not so 
remarkable, in form as those of the Rush, but nevertheless 
they are not the less interesting, seeing that every giant of 
200to 40.0 feet in height is simply made up of cell piled on 
cell to an infinite number. Their strength is, of course, 
vained by the form of the cells, the complete cohesion 
between them, and the thickening of the cell walls which go 
to form the wood of those Conifers. It is the argument then 
of scientific men that the whole functions of plant life may 
be carried on in a single cell, while those of the largest plants 
on the earth’s surface are merely built up of an aggregation 
of such individual cells just as the Pyramids of Egypt were 
built by piling one brick on the top of another. 
The second chapter of the book deals with the protoplast 
as a house-builder and house-furnisher. We have just been 
discussing the building of the house, so to speak, by plant 
life, and if we were to make a passing remark about the pro¬ 
toplast as house-furnisher we might say that everything 
which the root, stems, leaves, flowers, and fruits contain has 
been manufactured and built up by the protoplast, in the 
first place as a single unit, and in the second place by the 
great multiplication of these cells or units. Everything ob¬ 
tained from" the plant kingdom that is of service to mankind 
or the lower animals has been built up originally through the 
aid of this protoplast. The starch oi wheat, barley, and oats 
is, so to speak, some of the furniture of the house built up by 
the cell. Wax, honey, sugar, sago, rice, tapioca, oils, vege¬ 
table fats, and so forth, are merely some of the furnishings of 
the house built by this primaeval cell unit. 
All of the wonderful work done by this individual cell of 
plant life is brought about under the agency of sunlight and 
by means of the chlorophyll or leaf-green to be found in all 
plants having -green leaves or green stems. While dealing 
with this subject of leaf-green, we would refer to the author’s 
interesting note on plant life under deep sea conditions. It 
is here indicated that the red seaweeds are these which grow 
at the greatest depth in sea water. When such plants are 
unable to live below a certain depth no form of vegetable 
life exists, so that in the deeper portions of the sea there is 
no vegetable life of any kind. 
A number of plants are able to live although they do not 
possess this leaf-green, but they are all more or less either 
saprophvtes, living on dead vegetable matter, or parasites 
living on live plants. Such plants are able to obtain the 
necessary food from those upon which they are able to live, 
and can thus dispense with sunlight. Fungi of various 
kinds, of which the common Mushroom is a well-known 
example, belong to this class of plants. We have, however, 
some plants belonging to the higher order which have become 
degraded to the condition of parasites, and no more remark¬ 
able example perhaps is known than that of Raffiesia, illus¬ 
trated on p. 103. The whole plant is so degraded that it 
has been able to dispense with leaves, stems, and roots, and 
lives in the interior of the plant on which it feeds until about 
to bloom, when it produces a remarkable flower reaching a 
diameter of three feet in the larger specimens. 
A chapter is devoted to seed and root, and here, again, a 
large number of very curious forms of the lower orders of 
plant life are used to illustrate different stages of advance¬ 
ment or evolution from lower to higher forms. Amongst the 
lower orders that which corresponds to a seed in popular 
estimation is the spore, but some plants have not even spores. 
In the higher forms we have an immense variety of 
seeds differing in size and shape, and the young seedling 
which springs from the same at germinat on shows the early 
root and leaf stage of the baby plants, and here again many 
very interesting lessons are to be learned. 
It is characteristic of a dicotyledon to have only two seed 
leaves, but there are some interesting modifications or abnor¬ 
mal departures from this type. An oak in germination is shown 
to have three cotyledons. Three seed leaves we may state 
are of frequent occurrence in seed beds, but they may not 
all originate in the same way. For instance, in the Chinese 
Primrose, frequent examples may be found of one or both 
cotyledons becoming more or less divided so that the original 
two may constitute three or four according to the extent and 
the division of the original ones. In many cases, however, a 
third cotyledon is perfectly formed in the early stages of the 
embryo. Some remarkable examples are given of aerial roots 
amongst tropical plants including the Screw Pine, the Banyan 
tree, and the Mangrove. 
A chapter is devoted to stems, and is headed “ Nature's 
Woodcraft.” Numerous illustrations are given of the struc¬ 
ture of various types of stem, being drawn from specimens 
that require the aid of the microscope to see them. Numerous 
forms of stems are mentioned, and some of the more remark¬ 
able are illustrated ; but we presume the limits of space 
have not allowed discussion of the reasons that determine 
any particular shape. Some of the tropical twining plants 
assume remarkable forms in after life, owing to the thickening 
of the original twig around or upon the stems of the other 
plants. We have an instance here of the lianes or cables, 
consisting of climbing plants that continue to hold up 
gigantic trees even after the latter may have been uprooted 
by storms, so that the lianesAontinue to support trees to whose 
injury they have originally contributed. A very remarkable 
form of stem is that of the Bottle Tree of Australia, 
the trunk of which is short and swollen and probably 
serves the plant as a storehouse for water in the dry regions 
where it occurs. Illustrations and descriptions are also given 
of stems and branches that assume the form of leaves, though 
the flowers that proceed from their edges or midrib are a 
pretty sure indication that they are merely branches. A 
remarkable form of stem is that of the Welwitschia, allied to 
the Conifers, and which forms a dwarf trunk very much 
resembling a wooden Mushroom or table-like structure. 
A chapter is devoted to leaf beginnings and leaf forms, in 
which leaves of a great variety and character are described 
or delineated. The folding of these leaves in the resting or 
winter buds of trees is also an endless source of instruction for 
those who care to go into this interesting field. An illustration 
shows the beautiful folding of the Lady’s Mantle (Alchemiila) 
in the bud and half-expanded state. A study of the unfold¬ 
ing of leaves in general is, indeed, extremely interesting. It 
can be studied during winter by dissecting buds taken from 
the trees, but we think there is no more interesting time to 
