PROCEEDINGS OE THE PERTHSHIRE SOCIETY OP NATURAL SCIENCE. 
61 
are frequently protected from injury by being enclosed 
in a hard covering, which in some is the outer coat of 
the seed (e.g., nutmeg), while in others it is the inner 
layer of the carpel (stone of cherry, &c.) Other seeds (e.g., 
gooseberry) are enclosed in a soft jelly-like pulp, which 
seems to protect them. 
Few Scottish plants have the seeds themselves ex¬ 
posed, the attraction being found in a fleshy growth, 
called an aril, that Surrounds the seed, and is usually 
conspicuous in colour; but we find examples of such in 
the yew and the spindle tree (Euonymus). Among 
exotic plants a frequently-quoted instance of this method 
is the nutmeg, the seed of which is the size of a 
pigeon’s egg. It is covered with the fleshy mace, and is 
swallowed for this by large fruit-eating pigeons, and is 
widely dispersed by this means. At one time the Dutch 
tried to restrict the cultivation of nutmegs to the Banda 
islands, in order to retain a monopoly of them, and de¬ 
stroyed the trees on the other Malay islands; but their 
efforts were vain, as tire seeds were continually conveyed 
to these islands from Banda by the birds. 
Very commonly the walls of the carpel become 
fleshy in whole or in part, and remain indehiscent. 
Such fruits may be divided into the two groups of 
(a) berries, with the whole wall soft, enclosing numer¬ 
ous seeds; and (b) drupes, where the outer part of 
the wall is fleshy, but the inner layer is leathery or 
stony as in cherries, enclosing usually not more than 
two seeds, generally only one. Both groups are well re¬ 
presented among us. Of berries we have the gooseberry 
and currants, the barberry, privet, vacciniums, honey¬ 
suckle, crowberry, potato, Solomon’s Seal, and various 
others. Of drupes we have the cherry, gean, sloe, 
and a few others of a similar nature. The raspberry 
and bramble are merely masses of small drupes crowded 
on a slightly-fleshy stalk. A modification of the drupe 
is seen in the apple, pear, rowan, and others of the 
genus Pyrus, in which the leathery carpels are sunk 
completely into a cuplike fleshy flower - stalk which 
enlarges greatly as the seeds ripen. In the hawthorn, 
well known to be much eaten by many of our birds, the 
structure is much as in Pyrus, only the carpels are of 
stony hardness. In roses the flower-stalk is hollowed out 
and encloses a number of small one-seeded carpels, gener¬ 
ally mistaken for seeds. The rosehip is this flower-stalk 
much enlarged, fleshy, and sweet; it is very attractive to 
various animals. The strawberry, on the other hand, is a 
convex flower-stalk much enlarged, and becoming sweet 
and fleshy as the seeds ripen. The so-called seeds on its 
surface are small one-seeded earpels. They are swallowed 
with the edible part, and the seeds are protected by the 
carpels in their passage through the intestine. These are 
the various adaptations met with among our native plants 
that favour this mode of dispersion, but I may be per¬ 
mitted to note one or two additional parts that become 
fleshy in fruits of other lands. The mulberry at first 
glance looks not unlike a bramble, but is essentially 
different, being made up of a number of flowers, each con¬ 
sisting of a one-seeded ovary enclosed in two pairs of 
enlarged fleshy sepals. In figs there is what reminds us of 
a rose in its structure, but in the fig the hollow flower- 
stalk supports and envelopes a multitude of minute 
flowers, each one of which has a small one-seeded ovary,— 
the so-called seed of the fig. The flower-stalk is the eat¬ 
able part, and makes up the great mass of the fruit. 
In a few plants the bracts become fleshy, but this is 
rarely the case, and I am not aware of any example of this 
structure among Scottish species. The pine-apple (Ana- 
nassa sativa) shows it well, and its appearance is probably 
familiar to most persons now-a-days. 
Elastic dehiscence of fruits frequently occurs in certain 
orders of plants, notably among the Leguminesa and Qera- 
niacece. The mode of dehiscence of the former forces 
itself on one’s notice, to the ear at least, in the fine sunny 
days of autumn on any piece of ground overgrown with 
broom or whins. The sharp reports of the bursting pods 
are often to be heard on all sides in such circumstances. 
When the seeds are ripe in the fruits of this order, there 
are two lines from tip to base of the pod, viz., its two edges, 
where the structure renders them most liable to give way. 
In dry sunny weather some moisture evaporates, and con¬ 
traction of the walls of the pod follows. If this goes 
beyond a certain limit, it becomes too great for the resist¬ 
ance offered at these lines, which suddenly give way, the 
two halves burst apart, and the jerk throws out the seeds 
often to a distance of several inches, or even feet. In the 
wild geraniums each carpel usually contains only one seed, 
but generally five carpels are present in each flower. The 
ovaries are closely adherent in the flower to the base of a 
central column, while their long styles are adherent to the 
column nearly to their tips. When the seed is ripe, in dry 
weather, each ovary separates suddenly from its attach¬ 
ment, while the style remains adherent to the column, and 
thus throws the seed, as if from a sling, to some distance. 
In the nearly-allied wood-sorrel (Oxalis) the seed is thrown 
out by a different mechanism. The fruit is a capsule that, 
when the seed is ripe, bursts into five parts in which the 
seeds lie. Each seed has an outer coat or arillus in addi¬ 
tion to the usual coats, and this arillus is very elastic. 
When the fruit bursts the fleshy arillus contracts through 
