A New Record of Cerastium (Caryophyllaceae) from Iran with Emphasis on its Micromorphological Characteristics

Caryophyllaceae juss. is a large family. the center of its distribution is in the mediterranean region and adjoining parts of europe, and in western and central asia. the family has been divided into three subfamilies (bittrich 1993). genus cerastium l. belongs to the subfamily of alsinoideae fenzl. this genus is classified into two subgenera and three sections in flora iranica area. the aim of this paper is to describe a new record and to compare it with its close relative based on morphology and micromorphology of seed and pollen. during a revision of the genus cerastium in iran, cerastium pentandrum (l.) was identified as a new record according to m?schl (1988). cerastium pentandrum is reported from northwestern iran and the iranian plateau. it belongs to subgen. cerastium sect. orthodon ser. morphological characteristics, as well as a full description and distribution of the new record are provided. this taxon is compared with its closest relative c. balearicum hermann. the ultrastructure of seed and pollen is examined by sem.