In standing spring crops produced within the borders of Siedlce a strongly ruderal field community which was intermediate between the association of the orders Centauretalia cyani and Polygono-Chenopodietalia was found. The floristic diversity allowed to distinguish four forms of this phytocoenosis, i.e. the form from Spergula arvensis, a typical form, the form from Stellaria media, and the form from Lamium amplexicaule and Stellaria media. It was concluded that the main reasons for the occurrence of these types of phytocoenosis were the following factors: specyfic ecological conditions connected with the spring crop production, high dispersion of fields, and low level of agrotechny which made it easy for ruderal species to spread and settle.

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