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372 LIFK
It appears, from the numerous comparative studies of Alphonse de Candolle, that the general form of the area occupied by each plant is that of
an ellipse a little elongated from east to west, under the temperate, and
from north to south under the tropical latitudes. This natural arrangement is easily understood, for in the various zones the greatest diameter
of the ellipse ought to indicate the direction in which the climate presents
most equality over a more considerable extent. It is a remarkable fact
that the area occupied by the species is the more extensive the simpler
their organization is, and that they likewise seem to possess a greater antiquity. Thus the cryptogams, which are the least developed plants, occupy the largest surface. In the same way marine species have an average area more extensive than that of the terrestrial species; herbaceous
plants occupy a more considerable area than trees; and finally, the annual phanerogams have a country of larger dimensions than the perennial
and woody phanerogams. "The area "of plants is in inverse proportion
to the complication of their structure." It is also very remarkable that
from logical causes, probably anterior to the present state of the globe,
the average area of species diminishes gradually from the Arctic Pole in
a southerly direction.
No kind of flowering plant, not even the nettle and purslane, the most
faithful of the companions of man, inhabit the entire earth. Only eighteen species are reckoned which show themselves at the same time on
half the terrestrial surface, and the total number of known plants, which
each occupy a third ofthe globe, is only estimated at a hundred and seventeen. On the other hand, there are plants which botanists have never
discovered except in a single ravine or on an isolated promontory. The
many islands scattered in the ocean—St. Helena, Tristram d'Acunha, Juan
Fernandez, Madeira, and the Galapagos—possess the greater part of these
solitary plants not to be found elsewhere. But there are arso parts of the
continent where the species have their whole domain—a district of-a few
leagues or acres—which may be regarded as a sort of continental island.
As to the general superficial extent ofthe areas, it would be, according to
Alphonse de Candolle, about the hundred and fiftieth part of the earth's
surface—that is to say, nearly 180,000 square miles.
| Title | The ocean, atmosphere, and life |
| Creator | Reclus, Elisée |
| Publisher | Harper |
| Place of Publication | New York |
| Date | 1873 |
| Language | eng |
| Type | Books/Pamphlets |
| Title | 00000415 |
| Type | Books/Pamphlets |
| Transcript | 372 LIFK It appears, from the numerous comparative studies of Alphonse de Candolle, that the general form of the area occupied by each plant is that of an ellipse a little elongated from east to west, under the temperate, and from north to south under the tropical latitudes. This natural arrangement is easily understood, for in the various zones the greatest diameter of the ellipse ought to indicate the direction in which the climate presents most equality over a more considerable extent. It is a remarkable fact that the area occupied by the species is the more extensive the simpler their organization is, and that they likewise seem to possess a greater antiquity. Thus the cryptogams, which are the least developed plants, occupy the largest surface. In the same way marine species have an average area more extensive than that of the terrestrial species; herbaceous plants occupy a more considerable area than trees; and finally, the annual phanerogams have a country of larger dimensions than the perennial and woody phanerogams. "The area "of plants is in inverse proportion to the complication of their structure." It is also very remarkable that from logical causes, probably anterior to the present state of the globe, the average area of species diminishes gradually from the Arctic Pole in a southerly direction. No kind of flowering plant, not even the nettle and purslane, the most faithful of the companions of man, inhabit the entire earth. Only eighteen species are reckoned which show themselves at the same time on half the terrestrial surface, and the total number of known plants, which each occupy a third ofthe globe, is only estimated at a hundred and seventeen. On the other hand, there are plants which botanists have never discovered except in a single ravine or on an isolated promontory. The many islands scattered in the ocean—St. Helena, Tristram d'Acunha, Juan Fernandez, Madeira, and the Galapagos—possess the greater part of these solitary plants not to be found elsewhere. But there are arso parts of the continent where the species have their whole domain—a district of-a few leagues or acres—which may be regarded as a sort of continental island. As to the general superficial extent ofthe areas, it would be, according to Alphonse de Candolle, about the hundred and fiftieth part of the earth's surface—that is to say, nearly 180,000 square miles. |
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