Horsetails and Scouring Rushes are in a primitive genus (Equisetum) of non-flowering plants. Most of their stems are hollow and have distinct nodes, or swollen areas, where branches are sometimes attached. Both stems and branches have vertical ridges and grooves. Silica, embedded in the ridge tissue, led to the stems being used to scour pans as well as an abrasive for burnishing brass and finishing violins.
Equisetum leaves are barely recognizable as leaves – these pointed structures fuse into small sheaths surrounding each node. A spore-bearing cone forms at the tip of the fertile stems. If you look closely you will see that hexagonal plates (modified leaves) cover the surface of the cone. Underneath these plates are the sporangia, in which spores are produced. Upon maturation of the cone, the sporangia expand, split open and release their spores. (photo: Variegated Scouring Rush,Equisetum variegatum )
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