Taxonomic significance of anatomical characters in some species of Caryophyllaceae Family in Iraq

The anatomical characters of the leaves, trichomes and stems of 12 species of Caryophyllaceae family were studied. The results showed that the average of epidermal cells length in the adaxial surface ranged between 95.00 µm in Agrostemma githago and 29.5 µm in Agrostemma gracile, while in the abaxial surface, it ranged between 92.5 µm in A. githago and 35.62 µm in A. gracile. Stomatal complex was circular and elliptic-shaped. All species have four types of stomata: diacytic, anomocytic, paracytic and hemiparacytic. Trichome and their distribution does play significant role in the taxonomic delimitation, A. gracile trichomes have non-glandular hairs, while Arenaria balansae has non-glandular and glandular hairs. Two types of mesophyll appear to be a good diagnostic characteristic isobilateral in the Agrostemma species and dorsiventral (bifacial) in the remaining species as well as several sclerenchyma layers including thick and thin-walled cells that surrounded vascular bundle and also the petiole contains many layers of sclerenchyma cells. Stem shape and size were different between species. The stems had the greatest size (1064.50 µm) in Acanthophyllum bracteatum, while the smallest stem cross section (450.46 µm) in A. balansae. Cells were rich in druses crystals. Sclerenchymatous layers were observed in all species. The number of sclerenchyma was different between the species, so that, 12-23 layers in A. gracile and 4-7 in A. crassifolium.  Size of pith was different. The greatest was 280.22 mm in Agrostemma githago, while no pith was found in Polycarpon tetraphyllum and Arenaria balansae.