Equisetum fluviatile 水問荊、水木賊、溪木賊

Common name: Water Horsetail
Scientific name: Equisetum fluviatile 水問荊、水木賊、溪木賊
Genus: Equisetum 木賊屬
Family: Equisetaceae 木賊科, horsetail family

Origin: native

Date: 4th June

[002_1] Deciduous perennial, can grow to 1.5 m. Unbranched or irregularly branched shoot. Can found in low waters of ponds, lakes and ditches. The above plants are found in ponds.

[025_1] Young shoots emerging from the soil.

[025_2] Young shoot.

[007_2] Stem smooth (relatively compared to other spp. of horsetails.), with 10-30 obscure ridges.

[006_2] Stem sheath teeth small, black-tipped, lacking pale margins.

(vs dark tipped teeth with membranous margins on stem sheath in marsh horsetail, Equisetum palustre 犬問荊) 

[012] Stem sheath on lower stem.

[028_1] Stem sheath with 16 teeth in this individual.

[032_2] Central hollow (pith cavity 髓腔) large. (Gets a clean break and the stem is hollow if the stem is snapped.) 10-30 obscure ridges (16 ridges in this individual). 

[013] Stem with buds of lateral branches.

[013_1] Lateral buds emerging from the main stem.

[014_1] Lateral buds further down the stem.

[007_1] Longer lateral branches.

[008_1] Branch segments can now be seen.

[011] Even lower node showing the branches with the stem sheath.

[011_1] Enlarged photo above.
Note the lowest branch segments are similar length to the stem sheath.
(vs the lowest branch segments are longer than, or as long as the stem sheath in field horsetail, Equisetum arvense 問荊、杉菜 vs the lowest branch segments are shorter than the stem sheath in marsh horsetail, Equisetum palustre 犬問荊)

[011_2]

[009_1]  Green branch teeth and the branch segment.
(vs dark-tipped teeth on side branches in marsh horsetail, Equisetum palustre 犬問荊)

[022_1] Individuals with terminal cones.

[019_1]

[023_1] Much enlarged cones for this individual.

[006_1] Developing cone.

[018_1]

[015_1]

[017_1] Ripe cone.