In Scouts in the mid 60s, we were taught to identify scouring rush which settlers were supposed to have used to clean pots. Alas, I can no longer identify it—so I checked the web where I found.
Equisetum hyemale (aka Scouring Rush) [Equisetum, from the Latin, equus, "horse", and seta, "bristle, animal hair"; hymale, from the Latin, hiemis, "winter"]
Other common names include Common Scouring Rush, Rough Scouring Rush, Bottlebrush, Horsetail, Field Horsetail, Rough Horsetail, Pewterwort, Dutch Rush (UK), Prêle d'hiver (Qué), Skavfräken, Skavgräs, Skurfräken, Skäfte (Swe), Skavgras (Nor), Skavgræs (Dan), Kangaskorte (Fin), Eski(Is), Winter-Schachtelhalm (Ger), Biorag (Gaelic), Cola de caballo (Mex), Lalenikan ("scour grass" - Lenape), Raudosi, Vaseosi, Körbe Osjad, Kidad, Kiviosi (Estonia)
The common name "Scouring Rush" refers to one of its many early uses, as sections can be bundled together to form a pot scrubber; the sharp silica crystals it contains contribute to its scouring ability, but also make it toxic to livestock and humans if ingested. Another use for Equisetum hyemale is as a toy - either a whistle or using its sections to snap apart and back together (a la Tinker Toys.) A favorite of dragon flies, especially if planted near a pond or stream, but once established in a moist environment, it can be invasive.
Use Google Images to search on Equisetum hyemale for photos.
Pete