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VEGETABLE PHYSIOLOGY. 
conservatory. When the footstalks elongate and loosen the truss, it is the worst fault the Rhododendron 
can possess ; we ought not to be able to see between the flowers at any time." 
It is just now an interesting problem with cultivators, what horticultural value the new 
Sikkim species may possess. Should they prove cultivable, and equal Dr. Hooker's repre- 
sentations, some of them will be splendid acquisitions. — M. 
Stable ^{iijsiiilngtf. 
I 
By ARTHUR HENFREY, Esa., F.L.S., Lecturer on Botany at St. George's Hospital. 
GERMINATION. 
OTIHE independent bodies thrown off by perfect plants for the reproduction of the species, are called 
Ia. sjiores in the Cryptogamous, and seeds in the Phanerogamous plants ; these two kinds of bodies are 
very different in their nature and construction, the first representing an earlier stage of the second; 
thus the phenomena which are comprehended under the name of germination are very distinct in 
character in the two cases. The spore, as cast out from the parent capsule, consists of a single cell of 
microscopic size, possessing, apparently, two or more coating membranes, one of which, in the higher 
forms, is indeed said to be of a complex nature, consisting of a layer of very minute cells arranged Kke 
an epidermis. In the germination of the higher cryptogams, the spore undergoes a course of develop- 
ment which, in its early stages, may be compared to the production of the embryo in the ovule of the 
flowering plants, while still contained in the seed vessel ; and it is not until a subsequent period that the 
formation of the regular permanent organs of the plant commences. Thus, while the spore of the 
Conferva simply grows at once into a filament by elongating into a tube which becomes divided off into 
separate cells by the production of cross partitions ; the spore of the mosses is first developed, almost 
precisely in the same way, into a conferva-like germ, from which a bud at length arises, ultimately 
producing the regular moss stem with its leaves and capsules. In the ferns, again, the spore cell is 
first developed into a flat cellular plate resembling a Liverwort, upon which a bud is afterwards formed, 
whence the fronds of the regular form arise. This mode of development is rendered the more interesting 
from the fact that there appears to be good ground for believing that, in some cases, a process of 
fertilization, somewhat resembling that effected by pollen upon the ovules of flowering plants, takes 
place upon these germs after their complete separation from the parent — for example, in the ferns, as 
already described in this Magazine (p. 22). 
The most remarkable point, however, with regard to the germination of spores, is one that they 
have in common with seeds, namely, the capability of retaining their vitality in a state of rest for an 
indefinite period, when no injurious influence is allowed to act upon them. That this is possessed by some 
spores is proved by the frequently repeated experiment of raising ferns from spores taken from plants 
preserved in herbaria : and it seems impossible to doubt that a similar power resides in the spores of 
many lower cryptogams which only become developed in peculiar circumstances, as with parasitic Fungi, 
the spores of which must often be floating in the atmosphere, ready to germinate when they light on an 
appropriate nidus. Other spores seem to be more perishable, since M. Thuret found it impossible to 
make any but fresh spores of the Equiseta germinate. In general, warmth and moisture, as with seeds, 
are sufficient to stimulate spores into activity. It remains a question whether or not those of parasitic 
Cryptogams germinate on other bodies besides those on which the perfect form of the species is pro- 
duced ; the hypothesis that these spores produce fungi of different form according to the nidus upon 
which they germinate, is so contrary to our general notions of specific differences, that it requires much 
better proof than we have at present before it can be accepted. 
The germination of seeds is so familiar a phenomenon that it is merely necessary to dwell upon the 
peculiarities which distinguish it from that of spores, and the more str ikin g variations of character in 
different seeds. Almost all seeds contain a perfect rudiment of a plant, one or more leaf-like organs 
seated on the summit of a little root-like process, with a nascent bud between or within. In some cases 
this rudimentary plant or embryo, wholly fills the seed-coats, as in the Beans, Lupins, &c. : in such 
cases the leaf-like parts, or cotyledons are large and thickened, containing the nutrient matter to 
support the growing plant in the earlier stages of germination ; in other instances the embryo is com- 
paratively small, and is imbedded in a mass called the albumen, from which it draws its nourishment 
in the outset of its development. 
A certain number of plants have a more rudimentar}- fomi of embryo, as the orchis tribe, and many 
parasites, where no cotyledons can be distinguished ; such cases we may regard as instances of an arrest 
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