南极是指南纬66度5分 （南极圈） 以南的广大地区，总面积约6500万平方公里。整个南极大陆被一个巨大的冰层所覆盖，平均海拔为2350米，素有“寒极”之称，仅有冬、夏两季。由于海拔高，空气稀薄，及冰雪表面对太阳辐射的反射等，使南极大陆成为世界上最寒冷的地区，迄今为止，观测到最低气温为摄氏零下89.6度。

环境条件决定了南极是地球上植物最稀少的地区。南极大陆与世隔绝，陆地常年被冰雪覆盖，即使在短暂的南极夏季，也仅有5%的地区无冰雪覆盖，称为无冰区或白色沙漠的绿洲，主要分布在大陆边缘的沿海地区。由于南极的酷寒、干燥、风大、日照量极少、营养缺乏和生长季节很短，严重地制约了陆地植物的生长和发育，致使南极没有花草树木。在南极大陆的沿海地带及其附近的岛屿上，最常见、数量最多、分布最广的植物就是地衣和苔藓。经中国南极考察队植物学家考察发现，南极洲仅有850多种植物，其中3种开花的高等植物。在低等植物中，地衣有350多种，苔藓370多种，藻类130多种。

The Antarctic is Earth's southernmost continent, overlying the South Pole. It is situated in the southern hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14.4 million km2. About 98% of Antarctica is covered by ice, which averages at least 1.6 km in thickness.

It covers more than 14 million km2, making it the fifth-largest continent. The coastline measures 17,968 kilometres and is mostly characterized by ice formations.

On average, Antarctica is the coldest, driest and windiest continent, and has the highest average elevation of all the continents. Since there is little precipitation, except at the coasts, the interior of the continent is technically the largest desert in the world. There are no permanent human residents. Only cold-adapted plants and animals survive there, including penguins, seals, mosses, lichen, and many types of algae.

The climate of Antarctica does not allow extensive vegetation. A combination of freezing temperatures, poor soil quality, lack of moisture, and lack of sunlight inhibit the flourishing of plants. As a result, plant life is limited to mostly mosses and liverworts. The autotrophic community is made up of mostly protists. The flora of the continent largely consists of lichens, bryophytes, algae, and fungi. Growth generally occurs in the summer, and only for a few weeks at most.

There are more than 350 species of lichens and about 370 species of bryophytes, such as mosses. Seven hundred species of algae exist, most of which are phytoplankton. Multicolored snow algae and diatoms are especially abundant in the coastal regions during the summer. There are three species of flowering plants found in the Antarctic Peninsula, such as Deschampsia antarctica and Colobanthus quitensis.

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