sunflower stem, helianthus annuus, longitudinal section, 20x micrograph

20x anatomy annuus background biology botanical botany cell cells cut cytology education helianthus histology isolated lab layer light longitudinal magnification magnified micro microanatomy microbiology micrograph microscope microscopy microsection out photo photomicrograph plant research sample science section sectioned slide specimen stain stained stem sunflower visual white