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marsh horsetail, prêle des marais

dwarf horsetail, dwarf scouring-rush, prêle faux-scirpe, sedgelike horsetail

Sheaths

elongate, 4–9 × 2–5 mm;

teeth dark, 5–10, narrow, 2–5 mm, margins white, scarious.

green proximally, black distally, elliptic in face view, 1–2.5 × 0.75–1.5 mm;

teeth 3, dark with white margins, not articulate to sheath.

Aerial stems

monomorphic, green, branched or unbranched, 20–80 cm;

hollow center small, to 1/3 stem diam.;

vallecular canals nearly as large.

persisting more than a year, unbranched, tortuous, 2.5–28 cm;

lines of stomates single;

ridges 6.

Branches

when present only from midstem nodes, spreading, hollow;

ridges 4–6;

valleys rounded; 1st internode of each branch shorter than subtending stem sheath;

sheath teeth narrow.

Cone

apex pointed;

spores green, spheric.

2n

=216.

=216.

Equisetum palustre

Equisetum scirpoides

Phenology Cones maturing in summer. Cones maturing in summer, or cones overwintering and shedding spores in spring.
Habitat Marshes and swamps Wet woods, peat bogs, tundra
Elevation 0–1500m (0–4900ft) 0–1000 m (0–3300 ft)
Distribution
from FNA
AK; CA; ID; ME; MI; MN; MT; ND; NH; NY; OR; PA; VT; WA; WI; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; YT; Eurasia s to Himalayas; n China; Korea; Japan
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from FNA
AK; IA; ID; IL; MA; ME; MI; MN; MT; NH; NY; SD; VT; WA; WI; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; YT; SPM; Greenland; n Eurasia
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[BONAP county map]
Discussion

The name Equisetum palustre var. americanum has been used for specimens from the flora that have longer teeth than those from Eurasia.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 2. FNA vol. 2.
Parent taxa Equisetaceae > Equisetum > subg. Hippochaete Equisetaceae > Equisetum > subg. Equisetum
Sibling taxa
E. arvense, E. fluviatile, E. hyemale, E. laevigatum, E. pratense, E. ramosissimum, E. scirpoides, E. sylvaticum, E. telmateia, E. variegatum, E. ×ferrissii, E. ×litorale, E. ×mackaii, E. ×nelsonii
E. arvense, E. fluviatile, E. hyemale, E. laevigatum, E. palustre, E. pratense, E. ramosissimum, E. sylvaticum, E. telmateia, E. variegatum, E. ×ferrissii, E. ×litorale, E. ×mackaii, E. ×nelsonii
Synonyms E. palustre var. americanum
Name authority Linnaeus: Sp. Pl. 2: 1061. (1753) Michaux: Fl. Bor.-Amer. 2: 281. (1803)
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