Rose-like

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The division of living beings into systematics is a continuous subject of research. Different systematic classifications exist side by side and one after the other. The taxon treated here has become obsolete due to new research or is not part of the group systematics presented in the German-language Wikipedia.

The rose-like plants (Rosidae) form a subclass of the flowering plants (Magnoliophyta) in some systematics . They essentially correspond to the Rosids . The individual groups have produced a great variety of flower and growth forms and many are important as useful plants.

features

The flowers are predominantly radial symmetry , less often dorsiventral. They have a cyclical structure, five or four numbers. They have a double flower envelope : the calyx corresponds to the perigone of the Magnoliopsida and the simple Rosopsida . The petals have developed from an outer circle of stamens . The petals are mostly free, ie not grown together, so they were previously placed in a development stage "Dialypetalae". The androeceum usually consists of two circles (diplostemony). However, secondary, centripetal or centrifugal polyandry has occurred in some kin groups . In wind-flowered groups, the petals and stamens can also be reduced again (secondary apetaly and haplostemony).

The pollen grains are two or three nuclei. They are originally tricolpat , but the further shape is very diverse.

In the basal systems are the fruit leaves still available ( choricarpy ), but it outweigh overgrown carpels (coenocarpy). The ovules have two integuments and are crassinucellate. The secondary endosperm usually develops in a nuclear way.

The plastids of the sieve tubes are predominantly of the S type. Phytochemically, the Rosidae are characterized by the occurrence of trihydroxylated flavonoids (such as myricetin and leucodelphinidin), ellagic acid and ellagic and gallo tannins . Benzylisoquinoline alkaloids , betalaine , iridoids and indole alkaloids are largely or completely absent .

In this group, endosymbioses with air nitrogen- binding prokaryotes ( Rhizobium , Actinomycetes ) often occur , but these are limited to a few related groups: Rosales, Fagales, Fabales, Cucurbitales.

Crops

The orders are of great economic importance: Rosales , with numerous types of fruit such as apple , pear , cherry and wine ; furthermore the fabales with the legumes beans , peas , lentils , further soybeans and peanuts ; the sapindales include the citrus fruits ; to the Malpighiales the common flax or flax, the rubber tree and the cassava plant . Many timber from the temperate latitudes belong to the Fagales .

Systematics

literature

  • P. Sitte, H. Ziegler, F. Ehrendorfer, A. Bresinsky: Textbook of botany for universities. 34th edition. Founded by E. Strasburger ... Gustav Fischer, Stuttgart 1998.