Equisetum hyemale

Hollow, jointed stems rough with silica, historically used to scrub pots and pans (hence the common name Scouring Rush). A spore-bearing plant that produces cone-like strobili rather than flowers or fruit. Spreads aggressively via rhizomes; contain it or give it a wild corner to colonize. Good for rain gardens, pond edges, and other consistently wet spots, although we have some planted here in hot and dry full sun (see photos; contained as a foundation planting) and it seems fine.