Abstract:

This paper describes a floristic study of Bitlis river basin. The research was carried out from 2001 and 2003 to 2150 vascular plant specimens were collected. After the identification of the specimens, the flora was determined to include 925 taxa (at specific and infraspecific ranks) belonging to 770 species, 386 genera and 85 families. One hundred and seventy-nine taxa were defined as new records for the B9 square. The endemism rate of the area is 6.8% based on 63 taxa. The largest families are Asteraceae (109 taxa), Fabaceae (101 taxa) and Poaceae (77 taxa). The largest genera are Trifolium L. (27), Astragalus L. (22) and Silene L. (18). The phytogeographic elements are represented in the study area as follows: Irano-Turanian 292 (31.8%), Mediterranean 81 (8.7%) and Euro-Siberian 46 (4.9%). When the flora of the area is analysed by Raunkiaer’s life form system, the results are as follows: hemicryptophytes 345 (37.3%), therophytes 308 (33.3%), chamaephytes 103 (11.1%), cryptophytes 101 (10.9%) and phanerophytes 68 (7.35%). The descriptions of 29 species in our study were different in terms of some characteristics from the descriptions in the Flora of Turkey and in some cases from the flora of neighbouring countries.

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