Equisetum palustre |
Equisetum ramosissimum |
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marsh horsetail |
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Sheaths | rectangular, 5–10 mm, green; teeth 3–7 mm, persistent with a dark center and pale hyaline margins. |
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Aerial stems | annual, monomorphic; up to 80 cm tall, deeply grooved, green; ribs 5–10; central cavity less than 33% of the stem diameter. |
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Branches | in whorls; from the mid-region of the stem, numerous to sparse (rarely absent); ridges 4–6; first internode shorter than the sheath and not exserted. |
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Cones | pedunculate. |
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2n | =216. |
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Equisetum palustre |
Equisetum ramosissimum |
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Distribution | ||
Discussion | Swamps, marshes. 0–1200 m. Casc, WV. Northern North America; Asia, Europe. Native. Damaged green stems of E. arvense can sometimes produce cones and resemble E. palustre. However, the latter differs from E. arvense in the size of its central cavity (greater than 33% stem diameter vs. less than 33% in E. arvense) and the first branch internode (shorter than sheath vs. longer than sheath in E. arvense). |
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Source | Flora of Oregon, volume 1, page 79 Duncan Thomas |
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Sibling taxa | ||
Web links |
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