Carex is a vast genus of over 2,000 species[2] of grass-like plants in the family Cyperaceae, commonly known as sedges (or seg, in older books).

[3] The colour of foliage may be green, red or brown, and "ranges from fine and hair-like, sometimes with curled tips, to quite broad with a noticeable midrib and sometimes razor sharp edges".

[citation needed] The defining structure of the genus Carex is the bottle-shaped bract surrounding each female flower.

[6] The shape, venation, and vestiture (hairs) of the perigynium are important structures for distinguishing Carex species.

[citation needed] The fruit of Carex is a dry, one-seeded indehiscent achene or nut[3] which grows within the perigynium.

[4] Most (but not all) sedges are found in wetlands – such as marshes, calcareous fens, bogs and other peatlands, pond and stream banks, riparian zones, and even ditches.

[6] They are one of the dominant plant groups in arctic and alpine tundra, and in wetland habitats with a water depth of up to 50 cm (20 in).

[4] The genus Carex was established by Carl Linnaeus in his work Species Plantarum in 1753, and it is one of the largest genera of flowering plants.

The most influential was Georg Kükenthal's classification using four subgenera – Carex, Vignea, Indocarex and Primocarex – based primarily on the arrangement of the male and female flowers.

[4] The genus is now divided into around four subgenera, some of which may not, however, be monophyletic:[11] Several fossil fruits of two Carex species have been described from middle Miocene strata of the Fasterholt area near Silkeborg in Central Jutland, Denmark.

[20] During the first human expedition to the South Pole in 1911, such a mix were used in skaller, when camps had been set (after each stretch of travelling had been completed).

[21] Carsten Borchgrevink of the British Antarctic Expedition 1898-1900 reported "I found the Lapps method of never using socks in their Finn boots answered well.

The great thing seems to be to arrange the grass properly in the boots, and although we all tried to imitate the Finns in their skill at this work, none of us felt as warm on our feet as when they had helped us.