monomorphic adjective. 
[mɒnǝ(ʊ)'mɔ:fɪk] L19.[from MONO- + Greek morphē form + -IC.]Having or existing in only one form; monomorphous; 
esp. in 
Biology, (of a population or species) identical or homogeneous as regards morphology or genotype. 
 [TahlilGaran] English Dictionary ▲