A shrub ( lat. Suffrutículus ) is one of the life forms ( biomorphs ) of plants . In the classification system of life forms of Raunkier plants , shrubs belong to one of the four subtypes of the Hamefita type.
Often, semi-shrubs are called undersized shrubs and even confused with shrubs , two other life forms, which of course is not true. The differences between shrubs and shrubs are not in the height of the plant, but in the location of the buds, from which annual shoots are formed annually and also, in the scale of lignification of the perennial part. The differences between shrubs and shrubs are obvious, since the latter are purely woody plants, in which only leaves and generative organs die annually.
Description
Perennial semi - woody plants, with lignified bases of generative stems, which are represented only by the lower internodes that persist for several years on the soil surface (or at a small distance from it). Every year, from the buds located on them, annual shoots arise, some of which are lignified, thereby forming the skeletal structure of the crown . At the same time, generative shoots are grassy and completely die off at the end of the growing season .
There is a group of primitive shrubs (for example, some kermeks ( Limonium spp. ) And a whole group of wormwoods of the subgenus Seriphidium ) that carry a number of characteristics inherent in perennial herbaceous plants and are, as it were, a transitional link between them and true shrubs.
Semi-shrubs propagate mostly by seeds, but some of them are characterized by particularization , which occurs, for example, in sarsazan ( Halocnemum strobilaceum ), potash ( Kalidium spp. ), Cocpeca ( Atriplex cana ) and some others. Others, such as izen ( Kochia prostrata = Bassia prostrata ), are completely incapable of partitioning and their reproduction is exclusively generative (seed).
Representatives of this ecobiomorph are found in various flowering families. They are very numerous in the families haze , piggy , clear - headed , aster , leaf- leaved , franken, and a number of others.
The life expectancy of most shrubs, usually within 7-20 years.
Distribution
The shrubs, for the most part, are most characteristic of arid ecosystems - dry steppes , semi-deserts and deserts , both flat and mountainous. Their greatest number is found in warm-temperate latitudes , in the south it is limited, reaching only the subtropical zone. They grow on all continents (except Antarctica ). In particular, shrubs (mainly from the creeper and aster families) form the core of the floristic diversity of the Iranian-Turanian and partly North African deserts and semi-deserts, forming their characteristic appearance. Most of them are landscape plants of these territories.
Literature
- Bespalova Z. G. On the biology of semi-shrub- edificators of phytocenoses of Nogai desert steppes and dry steppes of central Kazakhstan // Botan. journal - 1960. - T. 45 , No. 10 . - S. 1462-1475 .
- Bespalova Z. G. On the life form of “shrubs” // Problems of modern botany . - 1965.- T. 2 . - S. 65-69 .