IUCN threat status:

Not evaluated

Comprehensive Description

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This native perennial plant is about 1½–3' long. It consists of a central stem that is erect or semi-erect; this stem often has whorls of 2-6 branchlets along the upper half of its length, otherwise it is unbranched. The central stem has about 15-25 fine ridges along its length; it is green to dark green. The stem diameter is up to 1/3" across; it has a very large interior cavity that spans at least 80% of the diameter. The central stem consists of several overlapping joints. Each joint is several inches long; its apex consists of an appressed ring-like sheath, from which the base of the next joint develops. This sheath is about ¾" in length and green to brownish green; it is often dark brown or black at the base, while its upper rim has about 18 tiny teeth that are dark brown or black. However, the sheaths and their teeth become whitish grey as they age. The jointed branchlets have an appearance that is similar to the central stem, except that they are smaller. These branchlets usually spread upward, rather than droop downward; unlike the central stem, they are always unbranched. The branchlets are hollow and they span a few inches in length. Each fertile shoot produces a spore-bearing cone that is about 1" long; this cone is usually rounded at the top and it occurs on a short stalk. Infertile shoots are similar to fertile shoots, except they lack spore-bearing cones; both types of shoots are deciduous, rather than evergreen. The spore-bearing cones are produced during late spring to early summer. After releasing their spores, they gradually wither away. The root system consists of extensive rhizomes and fibrous roots. This plant often forms vegetative colonies.


Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© John Hilty

Source: Illinois Wildflowers

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