Flora of North America species comparison

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Equisetum palustre

Equisetum ×litorale

marsh horsetail, prêle des marais

horsetail, prêle littorale, shore horsetail
Sheaths

elongate, 4–9 × 2–5 mm;

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

somewhat elongate, 3.5–8 × 2.5–6 mm;

teeth dark, 7–14, narrow, 1–3 mm.
Aerial stems

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

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

vallecular canals nearly as large.

monomorphic, green, branched or occasionally unbranched, 2–70 cm;

hollow center 2/3–4/5 stem diam.
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.

mostly from midstem nodes, ascending to spreading, solid;

ridges 4–5;

valleys channeled;

proximal whorls with 1st internode of each branch equal to subtending stem sheath, distal whorls with 1st internode of each branch longer than stem sheath;

sheath teeth attenuate.
2n

=216.

Equisetum palustre

Equisetum ×litorale
Phenology Cones maturing in summer. Cones maturing in early summer, but misshapen spores not shed.
Habitat Marshes and swamps Ditches, stream banks, wet meadows
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
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; CT; DE; IA; ID; IL; IN; MA; MD; ME; MI; MN; MT; ND; NE; NH; NJ; NY; OH; OR; PA; RI; SD; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; NT; ON; PE; QC; SK; YT
[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.)

Equisetum × litorale is a hybrid between E. arvense and E. fluviatile. It should be expected where the parents coexist. This hybrid has been mistaken for Equisetum palustre; the solid branches with long first internodes and channeled valleys distinguish it from that species.

(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. Hippochaete
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. scirpoides, E. sylvaticum, E. telmateia, E. variegatum, E. ×ferrissii, E. ×mackaii, E. ×nelsonii
Synonyms E. palustre var. americanum
Name authority Linnaeus: Sp. Pl. 2: 1061. (1753) Kühlewein: Beitr. Pflanzenk. Russ. Reiches 4: 91. (1845)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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