This study included four sp~ci~s of the genus Oenothera,
i.e. Q. nissensis ~ fiedleri, Q. biennis .!::. ~.
grandiflora, Q. coronifera renner and Q. odorata Jacy.
Karyotype studies were carried out on these species at
the mitotic metaphase stage. All species studied have the
same chromosome basic number (X = 7) in the somatic cell.
These chromosomes were metacentric, sub-metacentic, acrocentric
and subacrocentric. The following descnption surr~arizes
the characteristics of the studied material:
1- Q. nissensis: The average total length of the haploid
complement in the five cells studied ..•e.s 29.10+0.41 u ,
The mean length of the chromosernes ranged frorn 0.95
to 5.84 u , The idiogram showed that the 6th and 7th
chromosomes were subacrocentric.
2- Q. biennis: The average total length of the haploid
complement was 25.45..:t.0.1u2, The mean length af the
chromosomes ranged from 1.25 to 7.06 u , The Ldicqrara
showed that the 3rd chromosome was acrocentic with
a small satellite attaching to its short arm.
3- Q. coronifera: The average total length of the ha~loid
complement was 30.22..:t.0.u06, -The mean length of the
chromosomes ranged from 2.06 to 7.00 u , The idiogram
showed that the 6th and 7th chromosomes were subacrocentric.
4- Q. odorata: The average total length of the haploid
complement was 19.00..:t.0.u08, The mean length of the
chromosomes ranged from 1.51 to 4.49 u , The idiogram
showed that the 5th, 6th and 7th chromosomes were