Eriocaulon aquaticum (Hill) Druce
Eriocaulon pellucidum Michx.
Eriocaulon septangulare With.
Common Pipewort, Seven-angle Pipewort
These tiny plants are North American natives found at the perimeter of bogs and ponds, and in water up to about several feet deep.
Plants: These plants are easy to miss, sporting tiny flowers and nearly invisible leaves. They are up to ¾-39" (2-100 cm) in height (even up to 9' (2.7 m) according to some accounts), but that is a bit misleading. The ones I found were about 3" (7.6 cm) high, in mud exposed by drought. But underwater, the thin tubular stems extend to reach the surface. The stems are dark brown, twisted, leafless, with 5-7 ridges (hence the common name seven-angle pipewort).
Leaves: The leaves resemble a small tuft of grass, with thin, nearly translucent blades emerging from a basal rosette. They are ⅜-4" (1-10 cm) long, up to 16" (40 cm) when submersed, and ¹/₁₆-⅛" (1.6-3.2 mm) wide.
Flowers: The flowers are tiny whitish balls, ⅛-³/₁₆" (4-6 mm) around, comprised of many diminutive flowers. They are soft and easy to squeeze flat. They look grayish because the flowers are actually gray in color, but dense white hairs mostly obscure the flowers. In the water, the flowers poke just above the surface, the only portion visible.
Eriocaulon aquaticum at Minnesota Wildflowers
Eriocaulon aquaticum on the Connecticut Botanical Society's Connecticut wildflowers site
Eriocaulon aquaticum on Earl J.S. Rook's Flora, Fauna, Earth, and Sky ... The Natural History of the Northwoods
Eriocaulon aquaticum on eFloras
Eriocaulon aquaticum description by Thomas H. Kent, last updated 21 Oct 2016.