Spirogyra.

These digital images were taken through a Canon 40D attached to an Orthoplan microscope fitted with DIC optics.

There are over 300+ species of Spirogyra found around the world. They are unbranched filamentous algae and are found in fresh water usually in large clumps floating on top of the pond or lake; they do not attach themselves to the substratum. The alga feels very slimy to the touch and will slip easily out of the hand. The chloroplast is helically twisted within the periphery of the cell wall and is ribbon like in shape twisting its way all around the inside of the cell. Numerous pyrenoids are embedded within the chloroplast. The nucleus seen in some of the photographs below is attached to the cell wall by many protoplasmic strands, which again can also be seen. This alga can be used to demonstrate cytoplasmic streaming which can usually be seen in this alga especially when using phase contrast.

Three stands of the filamentous alga Spirogyra, showing the ribbon nature and pyrenoids of this common alga

	This Image shows a slightly magnified nucleus and also the nucleolus along with the cytoplasmic strands that attach the nucleus to the periphery of the cell wall. The nucleolus has been slightly darkened to give the viewer a better idea of where exactly it is in relation to the cell body.
	This image shows the cell nucleus within the single cell of the filament of spirogyra. Many single cell units go to making up a single filament of spirogyra. Note the cell walls on either side of the nucleus and also the ribbon chloroplast structure.

Spirogyra ribbon showing the pyrenoids.

This image shows the ribbon chloroplast that is wrapped around the inside of the cell wall. The green circular lumps that can be seen embedded within the chloroplast are storage organelles for starch and are called pyrenoids.

Outer cell wall of Spirogyra.

This image was taken with a X40 DIC objective and a further magnification of X1.5 with the Leitz vario tube which was especially made for the Orthoplan microscope. The image shows the outer cell wall and its striations.

Introduction to photomicrography.