furnished, are, perhaps, the most wonderful parts of their economy.
When the requisite conditions are present, these are generally
developed during the winter and spring months, and may be easily
recognized by their peculiar appearance. At first a forest of
hair-like stalks, of a pale pink color, rises above the general level
of the tuft of moss to the height of between one and three inches,
giving to the moss the appearance of a pincushion well provided with
pins. These stalks, through course of time, are crowned with little
wen-like vessels called capsules, which are covered at an early
stage with little caps, like those of the Normandy peasants, with
high peaks and long lappets--in one species bearing a remarkable
resemblance to the extinguisher of a candle--a curious provision
for protecting them alike from the sunshine and the rain, until the
delicate structures underneath are matured. When the fruit-stalk
lengthens and the capsules swell, this hood or cap is torn from
its support and carried up on the top of the seed-vessel, much in
the same way as the common garden annual, the Eschscholtzia or
Californian poppy is borne up on the summit of the cone-like petals
before they expand. When the seed-vessel is riper it falls off
altogether, and discloses a little lid covering the mouth of the
capsule, which is also removed at a more advanced stage of growth.
The mouth of the seed-vessel is then seen to be fringed all round
with a single or double row of teeth, which closely fit into each
other, and completely close up the aperture.
It is extremely interesting to note that the leaf is the type of
the plant in the moss as in the flowering plant; the veil being
merely a convolute leaf, the lid a metamorphosed leaf, the teeth
one or more whorls of minute, flat leaves. It is by no means rare
to find individual mosses in which leaves appear at the top of
the fruit-stalk in place of the spore-case, just as happens in the
phyllode of flowering plants, when the colored parts of the flower
are converted into green foliage.
Mosses possess in a high degree the power of reproducing such parts
of their tissue as have been injured or removed. They may be trodden
under foot; they may be torn up by the plow or the harrow; they may
be cropped down to the earth, when mixed with grass by graminivorous
animals; they may be injured in a hundred other ways; but, in a
marvelously short space of time they spring up as verdant in their
appearance and as perfect in their form as though they had never been
disturbed.
Mosses also possess the power of resisting, perhaps to a greater
extent than most plants, the injurious operation of physical agents;
and this likewise is a wise provision to qualify them for the uses
which they serve in the economy of nature. The influence of heat
and cold upon many of them is extremely limited; some species
flourishing indiscriminately on the mountains of Greenland and the
plains of Africa. They have been found growing near hot springs in
Cochin-China, and fringing the sides of the geysers of Iceland,
where they must have vegetated in a heat equal to 186 degrees;
while, on the other hand, they have been gathered in Melville
Island at 35 degrees, or only just above the freezing-point. Though
frozen hard under the snow-wreaths of winter for several months,
their vitality is unimpaired; and though subjected to the scorching
rays of the summer’s sun they continue green and unblighted. Even
when thoroughly desiccated into a brown, unshapen mass that almost
crumbles into dust when touched by the hand, they revive under the
influence of the genial shower, become green as an emerald; every
pellucid leaf serving as a tiny mirror on which to catch the stray
sunbeams. Specimens dried and pressed in the herbarium for half a
century, have been resuscitated on the application of moisture, and
the seed procured from their capsules has readily germinated. They
grow freely in the Arctic regions, where there is a long twilight
of six months’ duration; and they luxuriate in the dazzling,
uninterrupted light of the tropics. They are found thriving amid
moist, steam-like vapors, with orchids and tillandsias, in the deep
American forests; and they may be seen in tufts here and there on
the dry and arid sands of the Arabian deserts. It matters not to
the healthy exercise of their functions whether the surrounding air
be stagnant or in motion, for we find them on the mountain top amid
howling winds and driving storms, and in the calm, silent, secluded
wood, where hardly a breeze penetrates to ruffle their leaves.
Unlike the ferns, the size and number of which gradually diminish in
passing from tropical to temperate countries, the maximum of mosses
is found in cold climates, increasing in luxuriance, beauty, and
abundance as we approach the North Pole. Like the ferns, moisture and
shade are highly favorable to their growth and well-being; hence, as
a rule, they produce a larger number of species and individuals, and
spread over wider areas in islands and the vicinity of rivers and
lakes than in the interior of continents, unless when well wooded and
watered. Their favorite habitats appear to be rocky dells or ravines
at the foot of mountains, with streamlets murmuring through them and
dense trees interweaving their foliage over their sides and creating
a dim twilight in the recesses beneath. In such hermit seclusions the
botanist may expect to reap the richest harvest of species.
Mosses, in many instances, are limited to rocks and soils of the same
mineral character; their limits of distribution, and of the rocks and
soils possessing such character being identical. For instance, some
are confined to limestone districts and chalk cliffs; a calcareous
soil being indispensable to their existence. Others affect granite;
numerous species luxuriate in soil formed by the disintegration
of micaceous schist; while not a few are found growing chiefly on
sandstone and clay. Some are found only on and near the seashore;
others are confined to the beds of streams and cliffs moistened by
the spray of cascades, where, however impetuous the torrent may be,
they cling tenaciously to the rocks and form carpets of greenest
verdure for the white, glistening feet of the descending waters.
Some are restricted exclusively to trees whose trunks and boughs
they clasp like emerald bracelets; others lead a lonely, hermit-like
existence in the dim moist caves and crevices of rocks, where they
are discovered only by the glistening of a stray adventurous sunbeam
on the drops of dew trembling upon their shining golden leaves.
Mosses are sometimes found in an isolated state as single
individuals, but they are far oftener found in a social condition.
It is a peculiarity of the family to grow in tufts or clusters, the
appearance of which is always distinct and well-marked in different
species, and often affords a specific character. This disposition to
grow together, which is exhibited in no other plants so strongly,
redeems them from the insignificance of their individual state, and
enables them to modify in many places the appearance of the general
landscape. As social plants they often cover vast districts of land.
Along with the lichens they give a verdant appearance to the desert
steppes of Northern Europe, Asia, and America. Mixed with grass
they luxuriate in parks, lawns, and meadows, particularly in moist,
low-lying situations. They spread in large patches over the ground
in woods and forests; and at a certain elevation on mountain ranges
they take exclusive possession of the soil, forming immense beds
into which the foot sinks up to the ankles at every step, bleached
on the surface by the sunshine and rain, blackened here and there by
dissolving wreaths of snow which lie upon them through all the summer
months, and gradually decomposing underneath into black vegetable
mould.
The plants whose peculiarities have been described in the preceding
pages are called Urn Mosses, their fructification being urn-shaped,
furnished with teeth and closed with a lid. There is another large
class called Scale-Mosses, so closely allied to the true mosses that
they are frequently confounded even by an educated eye. There are
upward of a hundred species of scale mosses indigenous to Great
Britain and Ireland, some of which are so small as to be scarcely
visible and others much larger than any of the true mosses. With the
exception of a few prominent species, which are found in every moist
wood and on every shady rock, they are somewhat local and limited in
their distribution, many of them being remarkably rare and confined
to remote and isolated localities. The greatest number of species
occurs in the tropics; and nowhere do they luxuriate so much as in
the dark woods and mountain ravines of New Zealand. Some of them
grow in the bleakest spots in the world, and are to be found even at
a higher altitude than the urn-mosses on the great mountain ranges
of the globe. They form the faintest tint of green on the edges of
glaciers and on the bare, storm-seamed ridges of the Alps and Andes,
where not a tuft of moss or a trace of other vegetation can be seen;
and this almost imperceptible film of verdure, when cleansed from the
earth and moistened with water, presents under the microscope the
most beautiful appearance.
The peculiarities of these plants are so remarkable and interesting
that they deserve more than a passing notice. As a rule, to which,
however, there are a good many exceptions, they do not grow upright
in tufts like the mosses, but have a flat, creeping, lichen-like
habit, spreading over rocks and trees in closely applied circles
which radiate from a common centre. The whole typical plant is like a
series or necklace of roundish, flat, imbricated scales, several of
which branch from a common point in the middle. The leaves, unlike
those of the mosses, are entirely destitute of a central nerve, for
what is called the nervure in the membraneous or leafy species is
nothing more than the stalk itself on the edges of which the leaves
are fastened together in such a manner as to form apparently a
continuous whole.
The Hepaticæ, or scale-mosses, may be divided into two groups,
consisting of those species in which the vegetation is frondose, that
is, in which leaf and stem are confounded, and of those in which
the vegetation is foliaceous, that is, in which leaves and stem are
distinct.
The most interesting of all the frondose group of scale-mosses is
the common Marchantia or Liverwort (Marchantia polymorpha). It is
very common, creeping in large, dark-green patches over rocks in very
moist and shady situations, such as the banks of a densely wooded
stream in a deep, narrow glen, or the sides of rivers and fountains.
It may often be seen also on the moist walls of hothouses and in
the pots and tubs. It adheres closely to rocks, which it sometimes
completely covers with its imbricated fronds by the numerous white,
downy radicles with which the under surface is covered.
The second or foliaceous group of scale-mosses, in which the leaves
and stem are distinct, is called Jungermanniæ, and contains by far
the largest number of species and the richest variety of form and
color. On either side of the thread-like stem arise in a more or
less oblique position the membraneous overlapping leaves; while the
fruit-vessel springs from the end of the stem, and is produced upon
little silvery foot-stalks. It bursts into four valves, and when
fully expanded spreads out into the form of a cross. There is a class
of plants whose external appearance and mode of growth would indicate
that they belong to the tribe under review, but whose structure and
functions are so different that they are commonly supposed to bear a
closer analogy to the ferns. They occupy an intermediate position,
and form a connecting link between ferns and mosses; I allude to the
Lycopods, or club-mosses. They are usually found in bleak, bare,
exposed situations in all parts of the world, and sometimes attain a
large size; forsaking the creeping habit peculiar to the family, and
becoming slightly arborescent in tropical countries, particularly New
Zealand, rivaling in rank luxuriance the smaller shrubs of the forest.
The club-mosses are all very graceful and beautiful plants. The
Spanish moss (Lycopodium denticulatum) is a great ornament to
conservatories and hothouses, where it conceals with its luxuriant
drapery the mould in the pots, and keeps the roots of the plants
moist. Nothing can be lovelier or more elegant than a basket of
orchids in full flower, with clusters of this moss in careless grace
from its sides. Lycopods may be said to present the highest type of
cryptogamic vegetation, the highest limit capable of being reached by
flowerless plants.
The first pages of the earth’s history reveal to us very
extraordinary facts with relation to members and allies of the moss
tribe. The club-mosses, in particular, at a former period, seem to
have played a more important part, or to have found conditions more
suitable to their luxuriant development than is the case at the
present day. The two or three hundred species at present existing are
the mere remnant of a once magnificent group. Some of them are stated
to have formed lofty trees eighty feet high, with a proportionate
diameter of trunk. They are among the most ancient of all plants.
The oldest land-plant yet known is supposed to be a species of
lycopodium closely resembling the common species of the moors. In
the upper beds of the Upper Silurian rocks they are almost the only
terrestrial plants yet found. In the lower Old Red Sandstone they
also abounded; while they occupied a considerable space in the Oolite
vegetation. But it is in the Coal-measures that they seem to have
attained their utmost size and luxuriance, sigillaria, lepidodendron,
etc., being now considered by competent botanists to be highly
developed lycopodia. Along with ferns they covered the whole earth
from Melville Island in the Arctic regions to the Ultima Thule of the
Southern Ocean, with rank majestic forests of a uniform dull, green
hue.
EUROPEAN SEA-WEEDS
--P. MARTIN DUNCAN
The zones of life are (1) the littoral zone, or tract between
tide-marks; (2) the laminarian zone, from low water to fifteen
fathoms; (3) the coralline zone, from low water to fifteen fathoms.
Then come other zones leading to the great depths.
The broad-leaved tangles live in the laminarian zone, and it is
called so from their Latin name, and therefore they limit the plants
and animals of the shore, seaward.
It has been noticed that the animals and plants of the shores of our
coasts are not the same everywhere, and that in certain parts some
peculiar kinds are to be found. This is produced by climate, the
nature of the sediment on the shore, the geological nature of the
coast-line and inland parts, and the mineralogy of the district. And
with regard to this last, it may be noticed, that where the rocks
contain lime, or limestone and chalk, there certain shell-fish and
corallines abound; but where this mineral does not exist, there
they are comparatively or entirely absent. The British Islands,
extending to the north and south, and being washed by the North Sea,
the Atlantic, the German Ocean, and the Channel seas, come within
the limits of certain natural history provinces. One is called the
Boreal, and it extends across the Atlantic from Nova Scotia and
Massachusetts to Ireland, the Faroe Islands, and Shetland Islands,
and along the coast of Norway. That is to say, there are marine
animals and plants which are found on the American, Irish, Scottish,
and Norwegian shores, and which are either of the same kind or
species, or of the same genus or group.
The next province is the Celtic, and it includes the coasts of
England, Scotland, Denmark, southern Sweden, and the Baltic, and all
these places have animals of the shore and other zones in common. The
Channel Islands and parts of British south coasts come within range
of another province, called the Lusitanian, which is that of the west
coasts of France, Spain, and of the islands off the coast of Africa.
The Celtic province is that to which most of the British coasts
belong; and it is a subject of great interest to know that many of
the kinds of shelly mollusca, which are now living, lived in the last
geological ages, and their remains are found fossil; so that the
condition of the coast-lines and shores and a part of the assemblage
of animals and plants now living on them have a remote ancestry.
It is by no means easy to say where the seashore begins landward.
It may be limited by cliffs and mountain-ground, so that there is
but little shore, and the tide-water then comes up the sides of the
cliff; and it may reach for miles inland, among salt marshes, the
ditches of which have salt water and marine animals and plants in
them. Again, even when the shore is perfectly limited inland, there
are proofs that the sea is near, long before it is reached. Trees
usually get scarce, and often those which are seen are much gnarled
and bent and covered with lichens. A new set of flowering plants is
noticed, and the old favorites of the meadow and wood are absent;
and grasses, reeds, rushes, and many singular plants straggle on
the sand and pebbles, out of the range of the tide, but within that
of the spray sent in by a high wind. Common observation has enabled
even the most unscientific collectors of plants to recognize what
may be called a maritime, coast, or shore flora, just as they can
distinguish a marsh, mountain, or wood flora beyond the range of the
sea. A flora is the name for all the plants of a district, and it
has been found that the seaside and seashore floras of these islands
are very rich in kinds. Indeed, there are many little local floras
included in the great seaside one, for the landscape, the nature
of the rocks, and the vegetation of the shore, differ greatly in
different parts. Each particular landscape by the sea, and every kind
of soil there, has its little set of peculiar plants, some liking
limestone, others clay, many rejoicing in sand, and some even finding
nourishment among the highest pebbles.
Hence, on walking round British coasts, the plants, as a whole,
will differ from those found inland, and at every turn or change of
rock and scenery new kinds appear. But many of the inland plants do
go down far to the seaside, and the art of gardening and all sorts
of accidents have dispersed many plants which originally were not
dwellers near the sea; and, on the contrary, they have also removed
seaside plants, like sea-kale and asparagus, inland and into our
gardens. In many places, however, and where the sea comes up very
close, the inland plants are not found. There is a very remarkable
thing about this seashore and seaside flora, and it is this, that
nearly all the important groups, families, or genera of inland plants
have a kind or two in it, and that there are few extraordinary
novelties which would enable us to say that such a set of plants was
destined for the seaside. Thus the pod-bearing order, which contains
the pea, bean, clover, and such plants, has many species which are
only found near the sea. The toothed medick (Medicago denticulatus),
and the common melilot, love sand and gravel near the sea; the star
clover lives on a shingly beach near Shoreham; while two kinds of the
genus lotus live on dry places, two being found near the sea in Devon
and Cornwall. There is a vetch, with a pale purple flower, on the
pebbly beach of Weymouth, and another of a sulphur-color likes such
situations. Even the poppy order has a kind with large golden-yellow
flowers, with seed-cases from 6 to 12 inches long, living on sandy
seashores; and this “horned poppy” has a very interesting companion,
for a poppy with a bluish-white flower with a violet spot lives in
the fens and on sandy ground near the sea, and it is the kind which
yields opium. The cruciferous plants, of which the wall-flower,
the rocket, cabbage, mustard, etc., are examples, are well and
interestingly represented at the sea. There is a sea-stock living on
the sandy seacoasts of Wales, Cornwall, and Jersey. The wild cabbage,
the parent of all domestic cabbages, lives on cliffs by the sea; a
wild mustard is at St. Aubin’s Bay, Jersey; a white draba, not very
unlike the common whitlow grass, is on sandhills by the sea in Islay.
The scurvy grasses are all found on seashores, and constitute a
shore group. Finally, there are the purple sea-rocket and sea-kale,
loving sandy shores, and there is a rare wild sea-radish. Among
other well-known inland orders of plants, such as the violets, there
is a rare one with its flowers wholly yellow, or yellow with the
upper part purple, living on sands by the sea. Of another order, the
tamarisk may be seen close to the waves on the Essex coast; even the
pink tribe has a sea bladder-campion, an alsine, and a cerastium.
Again, the tree mallow lives on rocks by the sea. The rose tribe are
certainly not lovers of the seashore, but there is one kind belonging
to the whitethorn tribe (Cotoneaster) which ornaments the rocks of
the Great Orme’s Head, in Carnarvonshire; and a solitary kind of the
thick-leaved plants, a sedum, lives there also, loving the limestone
soil. The Corrigiola littoralis of the southwest of England has
white-stalked flowers. The sea-holly, with its blue flowers in a head
or umbel, lives on sandy seashores; the wild fennel, the Scottish
lovage, and the fleshy-leaved, whitish-flowered samphire love rocks
by the sea. The sea-carrot lives on the southwestern coasts.
The red valerian is found on chalk cliffs; but no other of its
tribe, or of the teazels or scabious set, is found particularly as
a seashore plant. Both the composite orders, of which the daisy
and the asters are examples, and which form so large a part of
the inland flora, have many seashore species. Thus, there is the
golden samphire, allied to the elecampane plant, the sea-diotis,
the sea-feverfew, and the sea-wormwood. There is, or was, a wild
cineraria on the rocks of Holyhead, and there is a thistle with pink
flowers which loves sandy places by the sea. The least lettuce likes
chalky places. One of the centaury kinds lives on sandy seashores,
and there is a seaside bindweed with very handsome pink flowers with
yellow bands. One of the bugloss tribe lives on northern seashores,
and there is a curious great snap-dragon which is to be found about
cliffs overhanging the sea. The primroses and pimpernels are not
inhabitants of the seashore, but two sets of plants, called glaux
and samolus, belonging to their order, frequent the shore and salt
marshes. Then there is the sea-lavender tribe with four kinds, all
living in England, or Ireland, on rocky shores and salt marshes;
and the thrift plant likes the shore as well as the mountain top, a
distribution which is noticed also in the sea-plantain. Many of the
spinach tribe, such as the glass worts, the sea-beet, the salsolas,
and the sea-purslane, inhabit the shores, and some of them were
formerly used in the preparation of barilla. Such a common thing as
the dock could hardly be found away from the sea, and there is really
a sea-dock found on the marshland; and the Channel Islands have a
sea-snake-weed. A thorny shrub with lancet-shaped silvery leaves,
and attaining the length of from four to six feet, frequents sandy
spots and cliffs, on the southeast and east coasts, and is called the
sea-buckthorn. There is also a sea-spurge. The wild asparagus, with
a stem not one-third of the height of the cultivated kind, but the
true parent of all asparagus, is a rare plant, but it has been found
at Kynance Cove, Cornwall, Callar Point, Pembroke, and at Gosford
Links in Scotland. Another important plant, the onion, has its
representatives on the rocks of Guernsey, and another called chives
is a Cornish cliff seaside dweller. The rushes have several kinds on
salt marshes and shores, and there is a plant called the zostera,
with long leaves, which flourishes under water on many parts of the
eastern coast. Belonging to the same botanical order is the Ruppia
maritima, found at Newhaven and Guernsey.