Segetal plants in complexes of utilization of space of the Siedlce city.
The aim of a paper is presentation of spatial distribution of segetal species in the area of Siedlce city as well as floristic analysis of agricultural complexes of utilisation of space (agricultural and garden-cottage complex). Floristic-ecological studies were carried out between 1999 and 2007 in a network of 48 squares studied of a side of 1 km. According to Jackowiak  7 complexes of utilisation of space were distinguished in the borders of the city: forest-meadow, intermediate, agricultural, garden-cottage, block building, tenement-house building, industrial-transport. In total 947 vascular plant species were noted in the area of Siedlce city, of which 8.7% (78 species) were classified as segetal plants. Many of them (26-18.2%) were included to common constituents of the flora of the city. Occurrence of segetal species in the area of the Siedlce city is not limited only cultivated fields. The species were also frequently noted in the ruderal communities in the center of Siedlce. Agricultural and garden-cottage complexes indicate a similar floristic richness (494 and 480 species). The highest share of segetal species was noted in tenement-house building (20.9%) and block building complexes (20.2%). Agricultural and garden-cottage complexes are also similar in their phytosociological composition with domination of meadow (21.3 and 19.8%) and ruderal species (16.8 and 19.6%). A high expansiveness of segetal species is also visible in their distribution in complexes of utilisation of space of the Siedlce city As much as 34 segetal species (43.6%) are widely distributed in all 7 complexes. They area such species, as, Capsella bursa-pastoris, Chenopodium album, Galinsoga parviflora, G. ciliata, Echinochloa crus-galli, Stellaria media, Lamium purpureum, Atriplex patula, Raphanus raphanistrum, Anthemis arvensis, Erodium cicutarium, Setaria pumila, Viola arvensis, Apera spica-venti, Sonchus arvensis, Fallopia convolvulus, Sonchus oleraceus and Myosotis arvensis. Only 9 segetal plants (11.5%) have a narrow occurrence range, limited to 1 complex of utilisation of space (agricultural or garden-cottage complexes). They are: Arnoseris minima, Galium spurium, Linum usitatissimum, Veronica agrestis, V. opaca, V. polita, Vicia sativa, Avena fatua and Bromus secalinus.