Riyadh Abas's scientific contributions

The current research was designed to study of pollen grains of the genus Centaurea L. of the Asteraceae. The study included 17 species (C. cardunculus, C. scleroleis, C. cana, C. balsamita, C. solsititialis, C. sinaica, C. behen, C. thracica, C. laxa, C. aggragata, C. vergata, C. ibrica, C. bruguiriana, C. Phyllocephalla, C. rigida, C. hylolepis and C. hylolepis ssp. Hylolepis). Samples utilized in the present study were collected from different areas in the middle and north of Iraq. A compound microscope was used to examine the slides of samples and records the required measurements. The properties of samples such as the length of the polar axis, the equatorial axis and the thickness of the grain wall were of each pollen grain were measured by using an ocular micrometer and photographed by the camera on the microscope. The results showed that the pollen grains were tricolporate, as it turned out that the size of pollen grains, the diameter of germination pore, the length of the colpus, the surface sculpturing, as well as the thickness of the wall (exine) of the pollen have a taxonomic value to isolate the species of the genus from each other.

This study assessed Achene morphology of 17 taxa of the genus Centaurea L. were collected from different areas in the middle and north of Iraq. the current study has 12 different features. Diagnosis and isolation of the studied species, on the basis of the variation in these features. The characteristics studied are shape, size, color and hilum achene, the connection area between achene and pappus and the length and color of pappus. The results showed that the isolation of the species process is profoundly dependent on many characteristics of the achene, for example, The shape of the fruit assisted to isolate the two species C. behen and C. vergata from other species, the size and color and the hilum of the achene were considerable in the diagnosis and separation of the species studied, as well as the presence or absence of the hilum appendages helped to segregate the species C. cana from other species, The margin shape of the connecting area and its length and color were important in the isolated species, as regards the shape of the margin, the species under study were divided into two groups: denticulate and entire, and the length and color of the pappus was substantial in the prognosis of the species.