AND AMERICAN RURAL SPORTS. 
147 
to the limitation of species to certain quarters of the globe, 
occur in the various tribes of cryptogamic plants. Lin- 
naeus observed, that as the germs of plants of this class, 
such as mosses, fungi, and lichens, consist of an impalpa- 
ble powder, the particles of which are scarcely visible to 
the naked eye, there is no difficulty to account for their 
being dispersed throughout the atmosphere, and carried 
to every point of the globe, where there is a station fitted 
for them. Lichens in particular ascend to great eleva- 
tions, sometimes growing two thousand feet above the 
line of perpetual snow, at the utmost limits of vegetation, 
and where the mean temperature is nearly at the freezing 
point. This elevated position must contribute greatly to 
facilitate the dispersion of those buoyant particles of which 
their fructification consists. 
Some have inferred, from the springing up of mush- 
rooms whenever particular soils and decomposed organic 
matter are mixed together, that the production of fungi is 
accidental, and not analogous to that of perfect plants. 
But Fries, whose authority on these questions is entitled 
to the highest respect, has shown the fallacy of this argu- 
ment in favour of the old doctrine of equivocal genera- 
tion. “ The sporules of fungi,” says this naturalist, “ are 
so infinite, that in a single individual of Reticularia maxi- 
ma, I have counted above ten millions, and so subtile as 
to be scarcely visible, often resembling thin smoke; so 
light that they may be raised perhaps by evaporation into 
the atmosphere, and dispersed in so many ways by the 
attraction of the sun, by insects, wind, elasticity, adhe- 
sion, &c., that it is difficult to conceive a place from which 
they may be excluded.” 
In turning our attention, in the next place, to the in- 
strumentality of the aqueous agents of dispersion, we can- 
not do better than cite the words of one of our ablest bo- 
tanical writers. “The mountain-stream or torrent,” ob- 
serves Keith, “ washes down to the valley the seeds 
which may accidentally fall into it, or which it may hap- 
pen to sweep from its banks when it suddenly overflows 
them. The broad and majestic river, winding along the 
extensive plain, and traversing the continents of the world, 
conveys to the distance of many hundreds of miles the 
seeds that may have vegetated at its source. Thus the 
southern shores of the Baltic are visited by seeds which 
grew in the interior of Germany; and the western shores 
of the Atlantic by seeds that have been generated in the 
interior of America.” Fruits, moreover, indigenous to 
America and the West-Indies, such as that of the Mimosa 
scandens, the cashew-nut, and others, have been known 
to be drifted across the Atlantic by the Gulf-stream, on 
the western coasts of Europe, in such a state that they might 
have vegetated had the climate and soil been favourable. 
Among these the Guilandina Bonduc, a leguminous plant, 
is particularly mentioned, as having been raised from a 
seed found on the west coast of Ireland. Sir Hans Sloane 
informs us that the lenticula marina, or sargasso, a bean 
which is frequently cast ashore on the Orkney isles, and 
coast of Ireland, grows on the rocks about Jamaica, where 
the surface of the sea is sometimes strewed with it, and 
from whence it is known to be carried by the winds and 
currents towards the coast of Florida. 
The absence of liquid matter in the composition of seeds 
renders them comparatively insensible to heat and cold, 
so that they may be carried, without detriment, through 
climates where the plants themselves would instantly 
perish. Such is their power of resisting the effects of heat, 
that Spallanzani mentions some seeds that germinated 
after having been boiled in water. When, therefore, a 
strong gale, after blowing violently off the land for a time, 
dies away, and the seeds alight upon the surface of the 
waters, or wherever the ocean, by eating away the sea- 
cliffs, throws down into its waves plants which would 
never otherwise approach the shores, the tides and cur- 
rents become active instruments in assisting the dissemina- 
tion of almost all classes of the vegetable kingdom. 
In a collection of six hundred plants from the neigh- 
bourhood of the river Zaire, in Africa, Mr. Brown found 
that thirteen species were also met with on the opposite 
shores of Guiana and Brazil. He remarked, that most of 
these plants were only found on the lower parts of the 
river Zaire, and were chiefly such as produced seeds capa- 
ble of retaining their vitality a long time in the currents 
of the ocean. 
Islands, moreover, and even the smallest rocks, play 
an important part in aiding such migrations, for when 
seeds alight upon them from the atmosphere, or are thrown 
up by the surf, they often vegetate and supply the winds 
and waves with a repetition of new and uninjured crops 
of fruits and seeds, which may afterwards pursue their 
course through the atmosphere, or along the surface of 
the sea, in the same direction. The number of plants 
found at any given time on an islet affords no test what- 
ever of the extent to which it may have co-operated to- 
wards this end, since a variety of species may first thrive 
there and then perish, and be followed by other chance- 
comers like themselves. 
Currents and winds, in the arctic regions, drift along 
icebergs covered with an alluvial soil on which herbs and 
pine saplings are seen growing, which often continue to 
vegetate on some distant shore where the ice-island is 
stranded. 
With respect to marine vegetation, the seeds being in 
their native element, may remain immersed in water 
