Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Equisetum fluviatile L.
- Family: Horsetail (Equisetaceae)
- Spores: May-August
- Field Marks: This species has tight, persistent sheaths with 15-20 distinct dark brown teeth
on its green stems. There are often whorls of short, slender branches which are produced
only on the upper half of the main stem.
- Habitat: Swamps, along shores, sometimes in shallow, standing water.
- Habit: Perennial herb from coarse rhizomes.
- Stems: Main stem upright, smooth, jointed, up to 3 feet tall, sometimes unbranched but
often with whorls of short, slender branches on the upper 1/2 of the stem.
- Leaves: Reduced to form sheaths, the sheaths tight, appressed, with 15-20 distinct, dark
- Fruiting Cones: Oblongoid, up to 1 1/2 inches long, early deciduous and usually not
observable late in the growing season.
- Notes: This species produces both fertile and sterile stems. Except for the reproductive
cone produced on the fertile stems, they are similar in appearance.
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