The sedge family, with approximately 5500 species and 90 genera worldwide, is the third largest monocotyledonous family. A unique combination of morphological and karyotypic features contributes to the rapid evolution and diversification, as well as a high level of endemism in some groups.
Morphological features and characteristics of the family
Sedges look like herbs. There is increasing evidence that the closest relatives of sedge sedges are calyx. Both families have chromosomes with a very peculiar structure. The centromeres, the attachment points of spindle-shaped fibers during meiosis, are not localized in one place near the middle, but are distributed diffusely along the length of the chromosomes. Both sedge and calyx have pollen, which is dispersed in the form of tetrads. Both families also have the same number of leaves in rows.
Sedge stems are often triangular, mostly solid, while grass stems are never triangular - they are usually hollow. Most sedge plants have a morphological appearance of herbaceous perennials with fibrous roots, triangular stems and three-row leaves. Many types of rhizomes of different lengths; in a number of them, rhizomes are important organs for storing nutrients. Sedge sizes vary from tiny plants less than 1 centimeter high to gigantic papyri, which can reach five meters.
Sedge Classification
Modern classification systems divide the sedge family into 2-4 subfamilies. Separation of the family into two subfamilies would lead to the subfamily of the anatomy (usually with hermaphroditic flowers) and the subfamily of sedge (with the same sex flowers). However, many botanists consider this division rather abstract.
Scientists divide sedge into four subfamilies in this way:
- Satiety. This is the largest subfamily, including about 70 genera and 2400 species. Representatives usually have perfect flowers in simple ears with often numerous helically arranged or double-row scales.
- Subfamily sedge Caricoideae. The next largest subfamily consists of 2100 species scattered among only 5 genera, and is characterized by unisexual flowers in spikelets enclosed in shoots.
- The subfamily Sclerioideae has about 14 genera and 300 species; its flowers are also homosexual, but the fruits are not covered by a similar shoot.
- Subfamily Mapanioideae. It has about 170 species in 14 genera. Strongly reduced same-sex flowers are tightly grouped in such a way as to mimic a single flower, the so-called pseudantium.
Distribution and diversity
Sedges contain about 5,000 species and, depending on the classification used, from 70 to 115 genera. Plants are distributed across all continents except Antarctica. Although there are a large number of species in the Arctic, temperate, and tropical regions, the diversity of genera is much greater in tropical regions. Many sedge species found in northern latitudes have a circumpolar distribution. Species found in tropical or warm temperate regions, with the exception of those that are widespread agricultural weeds, are usually limited to one continent.
The ecological diversity of sedges is enormous: species are found in almost all habitats, except for extreme deserts, marine and deep-sea ecosystems. Most species of the sedge family, however, are plants of a sunny or wet habitat (fresh and salt marshes, shores of ponds and lakes, meadows, wet prairies and savannahs, as well as wet tundra). Species that prefer sunny areas can also be found in artificially created habitats, such as ditches and canal banks. Many sedge species are found in undergrowths of various types of forests (both temperate and tropical). Some are adapted to specialized habitats, including sand dunes, freshwater lakes and streams, as well as rocks.
The following are some representatives of the sedge family, most of which grow everywhere in Russia:
- reeds;
- cobresia
- common grass sword;
- sedge;
- cotton grass;
- shenoplektus;
- to have;
- fimbristilis;
- cyperus.
Ecology of the family
The ecological significance of sedge is unusually high. They are often the dominant components of many biomes. Thus, they are crucial for primary productivity and many aspects of the continuous circulation of water in the atmosphere, i.e. evaporation, transpiration, condensation, precipitation and runoff. Fruits, and sometimes shoots, as well as sedge tubers are important food for many aquatic and amphibian animals. Large sedge plantations are also crucial as shelter for many mammals.
Sedge are not only important components of sustainable marshy soil communities, but also play an important role in their succession. Many species of annual and perennial sedge are the first colonizers on the lifeless soil of newly created biomes. In mature marshy soils, these species are replaced by perennial representatives. Sedge seeds can enter new habitats by dispersal, usually by birds. However, many species, especially those that undergo cyclic drying periods, have “dormant” viable seeds that are stored in the soil as a seed bank. The vegetation of such soils is rejuvenated from the seed bank under appropriate conditions, and does not fully rely on resettlement.
Economic importance
The sedge family cannot boast of a large number of useful crops. Of these, of course, the most important are Chinese water chestnuts and chufa or tiger nuts, varieties of yellow walnut sedge, grown mainly in Africa. In both species, edible parts are underground tubers. In boreal regions and mountainous regions, sedge species are often important pasture plants and can even be cultivated, such as the meadows of some sedge species in Iceland.
All over the world, many species of sedge are of regional importance in weaving baskets, screens, and even sandals because of their strong fibrous stems and leaves. Such plants are cultivated in India. Indigenous peoples on Lake Titicaca in the Andes use sedge to build small boats called balsas. Some large fast-growing sedges of wetlands are grown in ponds and tanks for domestic wastewater treatment because of their ability to absorb excess nutrients, in particular phosphorus and nitrogen.