parts of equisetum arvense horsetail sporophyte with fertile and sterile stems and titles

arvense background biology botanical botany elaters english equisetum fertile flora grass green herb herbal horsetail illustration isolated leaf medical medicinal medicine morphology part parts phytomorphology plant puzzlegrass rhizome root scheme snake sporangiophore spore sporophyte stem sterile strobili strobilus structure system title tuber vector white wild