Micromorphological studies on nutlets of some Onosma L. (Boraginaceae) species from Turkey

In this study,the nutlet micromorphology of 9 taxa of turkish onosma species viz.,o. sericeum willd.,o. cassium boiss.,o. rutilum hub.-mor.,o. sieheanum hayek,o. albo-roseum fisch. & mey. ssp. albo-roseum var. albo-roseum,o. in exspectatum teppner,o. auriculatum aucher ex dc.,o. heterophylum griseb and o. thracicum velen. was examined using both light and scanning electron microscopy. according to surface ornemantations,three main types,reticulate,rugose and elongated,and 2 subtypes (rugose and rugose-reticulate) were defined and illustrated. nutlet morphology of the examined specimens exhibits some variation in size and shape. nutlet size ranges between 2-7 × 1.5-5v mm. nutlets are ovoid,broadly ovoid oblong-ovoid and bipyrimidate.