May IG, 1895. 
JOURN'AL OF HORTICULTURE AND COTTAGE GARDENER. 
437 
much more restricted than in the other. Let us now examine the natural 
conditions under which seeds are commonly produced and dispersed, in 
relation to the retention of their vitality; and we shall learn how 
much more it depends on their nature, or natural means of protection, 
than on the seasons. An Oak tree sheds its acorns in the autumn, and 
the leaves which fall afterwards afford them some protection from frost 
and excessive dryness. But the leaves might be blown away from 
one spot, and the acorns exposed to intense frost or drought, either of 
which will speedily kill them. In another spot the leaves may drift 
into thick layers, with an excessive accumulation of moisture, causing 
decay of the underlying acorns ; and there are many other unfavourable 
conditions which may destroy the vitality of the acorn. It is apparently 
impossible, however, to preserve an acorn’s vitality by any artificial 
means for more than one season. 
The Scarlet Eunner Bean loses its germinative power on exposure 
to comparatively slight frost, the degree depending on the amount of 
moisture in it; yet it will retain its vitality for an almost indefinite 
period under favourable artificial conditions. In both of the examples 
given, germination would naturally follow as soon after maturation as 
the conditions allowed. The seeds of the Hawthorn behave differently. 
Bach haw contains normally three to five seeds, every one of which is 
encased in a hard, bony envelope, in addition to its proper coat or testa. 
Committed to the earth, and under the moat favourable conditions, 
these seeds do not germinate till the second year, and often not so soon. 
In this instance prolongation of vitality is probably due in some 
measure to the protective nature of the shell enclosing the seed. 
Returning to seeds in which the embryo or plantlet forms only a 
very small part of the whole body. Wheat may be taken as a familiar 
and easily observed illustration of a seed, the vital energy of which 
requires very little to stimulate it into active growth ; and yet this 
same one, having no special protection in the way of coating, will 
retain its vitality as long, perhaps, as any kind of seed, if not under 
the influence of moisture. The primary condition to the preservation 
of vitality in a seed is perfect ripeness. Unripe seeds of many kinds 
will germinate and grow into independent plants if sown immediately 
after removal from the parent. The facility with which immature 
Wheat will germinate is most disastrously exemplified in a wet 
harvest, when the seeds will sprout while the corn is standing or in 
sheaf; thus destroying more or less completely the value of the grain 
for flour, as the starch or flour is consumed in the development of the 
embryo, or what is left is so deteriorated by chemical change that it is 
not good for food. There is perhaps no other seed more susceptible to 
moisture, and none less affected by dryness, or by heat or cold in the 
absence of moisture. 
The kind of vivipary exhibited by the Wheat is occasionally observed 
in various other plants ; and sometimes the seeds of pulpy fruits germi¬ 
nate in the fruit. There is also a class of plants in which vivipary is 
normal. Prominent in this class are the Mangroves (Rhizophorem and 
others) of seashores in the tropics. In these plants there is a remarkable 
adaptation to conditions, which insures their reproduction. From the 
very inception of the embryo there is no apparent interruption of active 
vitality in its development and germination. In the earliest stage the 
cotyledons or seed-leaves are formed, and the radicle or future primary 
root is represented by a very small point. When the former have 
attained their full development, which is not great, the latter begins to 
grow and rapidly increase in size. Each fruit or seed vessel, it should 
be mentioned, contains only one seed, the rootlet of which points to 
the apex of the fruit. Soon this rootlet pushes its way through the 
apex of the fruit, and grows into a spindle-shaped body of great density 
and length ; the cotyledons or seed leaves remaining partly inside 
the fruit, and acting as an organ of absorption from the parent 
plant to nourish the seedling. In Rhizophora mucronata this radicle 
attains a length of 2 to 3 feet, and the seedling eventually falls, and 
by its own weight penetrates and sticks in the mud, leaving the fruit, 
containing the exhausted cotyledons, attached to the tree, where it dries 
up. Another singular adaptation to conditions is the vital development 
of the seeds of aquatic plants which ripen their seeds on or under water. 
Vallisneria is a remarkable instance of this. The unisexual flowers are 
formed under water ; the female on long coiled stalks, which at the 
right period uncoil, and the flower rises just above the surface of the 
water. Simultaneously the short-stalked male flowers are detached from 
the base of the leafstalks, and also rise to the surface. After impreg¬ 
nation has taken place, the stalk of the female flower coils up again, and 
draws the seed vessel down under water, where the seeis ripen. 
It has been explained that heat, moisture, and air are necessary to 
the germination of seeds, varying immensely for different seeds. We 
come now to the behaviour of certain seeds under the influence of an 
unusual or unnatural amount of moisture, heat or cold, especially in 
relation to the length of the duration of exposure to any one of 
these factors. It has been proved beyond dispute, by actual experiment, 
that the vitality of certain seeds, notably various kinds of Bean and 
Convolvulus, is not impaired by immersion in sea-water—or rather 
floating and partially submerged—for a period of at least one year ; and 
that after having been kept quite dry for two or three years. Plants 
are actually growing at Kew from seeds treated as described ; and some 
years ago several seeds of Entada, cast ashore in the Azores, whither 
they had been transported by the Gulf Stream, were raised at Kew. 
So far as at present known, all the seeds that will bear very long 
immersion without injury have an intensely hard, bony, or crustaceous 
coat, that would withstand boiling for a minute or two without killing 
the embryo. Yet it is difficult to understand this power of resistance, 
especially after being kept dry for a long time. This imperviousness to 
water explains the wide distribution of many seaside plants, the seeds of 
which are conveyed by oceanic currents. How long such seeds would 
retain their vitality in water is uncertain, because experiments have not 
reached the limit. Many readers will remember Darwin’s experiments 
in this connection ; but it should be borne in mind that they were 
chiefly with seeds of plants not at all likely to be dispersed by the sea. 
It has already been stated that some seeds will bear immersion in 
boiling water for a short time, and gardeners occasionally practise this 
treatment to accelerate the germination of hard-coated seeds. But seeds 
of all kinds will bear for a considerably longer period a much higher 
dry temperature than soaking in water of the same temperature. It is 
recorded, by trustworthy authorities, that the seeds of many plants— 
Poppy, Parsley, Sunflower, and various kinds of grain, for instance—if 
perfectly dry, do not lose their vitality when subjected to a temperature 
of 212° F. for forty-eight hours ; and for shorter periods to a much 
greater heat. The result in most cases, though not all, is a considerable 
retardation of germination. Dry grain is equally impervious to cold. 
In 1877, seedling Wheat was exhibited at the Linnean Society that had 
been raised at Kew from grain that had been exposed to the intense 
cold of the Arctic expedition of 1874 to 1876. 
The next question that arises is. How long do seeds retain their 
vitality when stored in the ordinary ways adopted by dealers ? As a 
rule, seedsmen and gardeners prefer new seeds, because a larger per¬ 
centage germinates ; and mixing old seeds with new tells its own tale 
in irregular germination. Nevertheless, there are many seeds that 
retain their vitality from five to ten years sufficiently well to be 
depended upon to yield a good crop. Old Balsam seeds, other things 
being equal, have the reputation of yielding a larger proportion of double 
flowers than new ; and some gardeners consider that Cucumber seeds of 
four or five years of age give better results than those of the previous 
year. As already mentioned, perfectly ripened seeds will retain their 
vitality longer than those imperfectly ripened. In illustration of this, 
we note that Carrot seeds grown in France retain their germinative 
power, on the average, longer than English-grown seeds, owing to 
climatal differences. 
There is one other natural condition in relation to the vitality of 
seeds that should be mentioned : that is, the duration of the vitality of 
seeds on the mother plant. Some of the Australian Proteacere, and 
some of the Fir trees, especially North American, bear the seed-vessels 
containing quick seeds of many successive seasons ; and only under the 
influence of excessive drought or forest fires do they open and release 
the seeds. Rapid forest fires are often not sufficient to consume the 
cones, but enough to cause them to open and free the seeds for a 
succession of trees. The unopened cones of thirty years have been 
counted on some Fir trees ; and it is averred that the first seed-vessels 
of some proteaceous trees do not open to shed their seeds, under ordinary 
conditions, until the death of the parent plant, so that a tree may bear 
the accumulated seeds of half a century or more. 
Finally, a few words respecting the extreme longevity attributed to 
certain seeds. The reputed germination of “ mummy Wheat,” from 
two to three thousand years old, has been the theme of much writing ; 
but the results of careful subsequent experiments with grain taken from 
various tombs do not support the doubtless equally conscientious, though 
less skilfully conducted, experiments, supposed by some persons to have 
established the fact of Wheat of so great an age having germinated. 
Indeed it is now known that the experiments mainly relied on to 
prove this long retention of vitality were falsified by the gardener who 
had charge of them. Nevertheless, there is no doubt that some seeds do 
retain their vitality for a very long period, as is proved by numerous 
well-authenticated instances. 
Almost every writer on physiological botany cites a number of 
instances. Kidney Beans taken from the herbarium of Tournefort are 
said to have germinated after having been thus preserved for at least 
100 years. Wheat and Rye are also credited with having retained their 
vitality for as long a period. Seeds of the Sensitive Plant (Mimosa 
pudica) kept in an ordinary bag at the Jardin des Plantes, Paris, germi¬ 
nated freely when sixty years old. A long list might be made of seeds 
that have germinated after being stored for twenty-five to thirty years. 
If seeds retain their vitality for so long a period as this under such 
conditions, it is quite conceivable that seeds buried deeply in the earth, 
beyond atmospheric influences, and where there was not excessive 
moisture, might retain their germinative power for an almost indefinite 
period ; and the fact that plants previously unknown in a locality often 
spring up where excavations have been made, bears out this assumption. 
The same thing happens in arable land should the farmer plough deeper 
than usual; and deeper tillage, which would otherwise be beneficial, is 
often avoided on this account. 
A careful writer like Bindley states, though without qualification, 
that he had Raspberry plants raised from seeds taken from the stomach 
of a man whose skeleton was found 30 feet below the surface of the 
ground. Judging from coins found at the same place, the seeds were 
probably 1600 or 1700 years old. One more example of seeds germinating 
that are supposed to have been buried some 1500 to 2000 years. About 
twenty years ago on the removal of a quantity of slack of the ancient 
silver mines of Greece, several plants sprang up in abundance previously 
unknown in the locality. Among these was a species of Glaucium, 
which was even described as new; and it is suggested that the seed may 
have lain dormant for the long period indicated. But there is not the 
amount of certainty about any of these assumed very old seeds to 
convince the sceptical or to establish a fact. It remains yet for some¬ 
body to institute and carry out careful investigations where excavations 
are being made.— W. Botting Hemsley (in “Nature”). 
