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Diphasiastrum sitchense — Sitka ground-cedar

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Facts

Sitka ground-cedar is a rare inhabitant of exposed alpine and subalpine sites in Maine and New Hampshire, though it sometimes occurs in disturbed habitats at lower elevations in northern Maine. Hiker traffic and erosion are potential threats to alpine populations of this rare plant.

Habitat

Alpine or subalpine zones, anthropogenic (man-made or disturbed habitats), meadows and fields

New England distribution

Adapted from BONAP data

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North America distribution

Adapted from BONAP data

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Characteristics

Habitat
terrestrial
New England state
  • Maine
  • New Hampshire
Leaf shape
the vegetative leaves are short and scale-like
Spore leaf arrangement
the sporophylls are located on spore cones at the tips of the shoots or branches
Form of shoot
the plant has an upright stem, and the stem has simple branches
Horizontal stem
the horizontal stem is on the surface of the ground
Leaf differences
the vegetative leaves within a node are all similar in size and shape
Teeth on leaf edges
the edges of the vegetative leaves have no teeth
Spore leaf length
1.8–3.6 mm
Leaf outline
the vegetative leaves are widest above the base, then taper narrowly towards the tip (lanceolate)
Show all characteristics

  • Clonal plantlets

    Gemma arrangement
    NA
    Gemma shape
    NA
    Gemma width
    0 mm

  • Leaves

    Leaf differences
    the vegetative leaves within a node are all similar in size and shape
    Leaf length
    3.4–5.6 mm
    Leaf orientation
    the vegetative leaves are pressed against the stem
    Leaf outline
    the vegetative leaves are widest above the base, then taper narrowly towards the tip (lanceolate)
    Leaf ranks
    5
    Leaf shape
    the vegetative leaves are short and scale-like
    Pores on leaves
    there are pores on both sides of the vegetative leaves
    Spore leaf length
    1.8–3.6 mm
    Teeth on leaf edges
    the edges of the vegetative leaves have no teeth

  • Place

    Habitat
    terrestrial
    New England state
    • Maine
    • New Hampshire
    Specific habitat
    • alpine or subalpine zones
    • man-made or disturbed habitats
    • meadows or fields

  • Spores or spore cones

    Cone base at stem
    the base of the spore-cone does not have a distinct stalk
    Cone stalk branching
    • NA
    • the stalks bearing the spore cones are unbranched
    Cone thickness
    At least 0 mm
    Cone width
    3–5 mm
    Length of cone
    4.5–38 mm
    Number of cones
    1
    Quillwort itssue covering spores
    NA
    Same or different spores
    there is only one type of spore present
    Spore girdle
    NA
    Spore leaf arrangement
    the sporophylls are located on spore cones at the tips of the shoots or branches
    Spore leaf lifespan
    the sporophylls wither and fall off at the end of the growing season
    Spore leaf orientation
    the sporophylls are pressed against the spore cone
    Spore leaf shape
    the spore-bearing leaves are small and scale-like
    Spore leaf teeth
    The edges of the spore-bearing leaves are smooth, and without teeth
    Spore texture
    the spore surface has a net-like pattern on it (reticulate)
    Sterile tip of cone
    the spore cone does not have a slender, sterile tip (the whole cone produces spores)

  • Stem, shoot, branch

    Branch cross-section
    the outermost level of branches are round, elliptic or semicircular in cross-section
    Branch form
    the branches are smaller than the main stem
    Constriction zones
    • there are constricted zones on the horizontal stem where the leaves are smaller smaller or closer together
    • there are constricted zones on the vertical stem where the leaves are smaller smaller or closer together
    Form of shoot
    the plant has an upright stem, and the stem has simple branches
    Horizontal stem
    the horizontal stem is on the surface of the ground
    Horizontal stem thickness
    1–2.7 mm
    Stem height
    55–175 mm

Wetland status

Not classified

In New England

Distribution

Connecticut
absent
Maine
present
Massachusetts
absent
New Hampshire
present
Rhode Island
absent
Vermont
absent

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Maine
extremely rare (S-rank: S1), threatened (code: T)
New Hampshire
extremely rare (S-rank: S1), endangered (code: E)

From Flora Novae Angliae dichotomous key

3.  Diphasiastrum sitchense (Rupr.) Holub NC

Sitka ground-cedar. Diphasium sitchense (Rupr.) A. & D. Löve; Lycopodium sabinifolium Willd. var. sitchense (Rupr.) Fern.; L. sitchense Rupr. • ME, NH. Alpine areas, frequently on open, stony plains or near the summit of snow bank gullies; also in disturbed habitats in boreal areas, such as fields and borrow pits.

3×4. Diphasiastrum sitchense × Diphasiastrum tristachyum → Diphasiastrum ×‌sabinifolium (Willd.) Holub is a somewhat rare but widespread ground-cedar hybrid known from ME, NH, VT that frequently occurs in the absence of its parents. It has somewhat compressed lateral branches with 4 ranks of trophophylls that are adnate to the branches 50–60% of their length (most species, except D. sitchense, 
with trophophylls adnate more than 60% of their length), and shows a gradual transition from stobilus stalk trophophylls to strobilus sporophylls.

Native to North America?

Yes

Sometimes confused with

Spinulum canadense:
branches mostly 6-10 mm thick inclusive of the leaves, with bristle-tipped leaves in usually 4 ranks (vs. D. sitchense, with branches mostly 1.7-2.5 mm thick inclusive of the leaves, with pointed, but not bristle-tipped, leaves in 5 ranks).

Synonyms

  • Diphasium sitchense (Rupr.) A. & D. Löve
  • Lycopodium sabinifolium Willd. var. sitchense (Rupr.) Fern.
  • Lycopodium sitchense Rupr.

Family

Lycopodiaceae

Genus

Diphasiastrum