Centaurea hausknetchii is a local endemic species growing only in the Nemrut Mountain Historical National Park in the Southeast Anatolian region of Turkey. It grows in three small areas of this mountain and all these areas are under heavy grazing pressure. The germination behaviour of the seeds was studied and for this purpose seeds were left under two different photoperiods (8 h light-16 h darkness and 16 h light-8 h darkness) and treated with different concentratios of NaCl, KNO(3), H(2)SO(4) and HCl solutions. There was no germination in 3 % NaCl, 1-3 % KNO(3), 1-3 % H(2)SO(4) and 2-3 % HCl concentrations in each photoperiod. According to the univariate variance analysis of germination Lest results, germination media with different salts, nitrate and acid concentration (e.g., 0.5 %,1.0 %, 2.0 % NaCl; 0.5 %.1.0 %.2.0 %,3.0 % KNO(3); 0.5 % H(2)SO(4); 0.5 %, 1.0 % HCl) under different photoperiods (8 h light-16 h darkness and 16 h light-8 h darkness and 24 h light) and control have been investigated. The photoperiod and photo period-treatment interaction had a significant impact on the germination percentage and rate (p < 0.05). C. hausknetchii is in the critically endangered category (CR) in the IUCN 2000 Red Data Book. The habitat characteristics of the distribution sites were thus investigated, vegetative growth behaviour followed and interrelations between the increase and spread of populations recorded. The factors effecting the productivity were determined. This report will be helpful in the population biology studies and development of alternatives for effective protection programme.