This is quite an odd looking plant. We had noticed this, ribbed bright green stalk with junctions. At the junctions rings of upward pointing green branchlets can grow. Or the stems can remain bare of branches. I have read that it is the fertile plants that don’t have branches, but I’ve also read that branches occur in nutrient-rich places. Water Horsetail has a rounded cone, whereas Marsh Horsetail has a pointed cone. The cones turn black in June-July when the spores ripen. It likes a wet habitat – shallow water, damp ground and watermeadows.