This picture was made with a scanning electron microscope and shows a cross section through a mature "stem" section from Cryptocoryne usteriana. The "stem" is short in this species, consisting of older leaf scars and vascular tissue, which will elongate to at most a few centimeters as the plant ages. What is most interesting is the presence of abundant pin-like structures thought to be raphides. Rather than being explosively released as is usually described, these appear to have been stored rather passively in larger vacuoles within the stem structure and released, without violence, in packs when the stem was sectioned. Raphides were scattered individually, and in bunches as depicted here, promiscuously over the entire cross section. Click on the image for a larger image and more information.

Cryptocoryne Starch Grains

This picture was also made under a scanning electron microscope of a stem cross section of Cryptocoryne usteriana and was chosen because of the details within the cell structure. Each cell in this section is stuffed with solid granules. While not readily provable, these would seem likely to be starch crystals. Many aroids are known for their starchy tissues and they are used by humans as food in many countries. Click on the image for a larger image and more information.