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Diphasiastrum complanatum — northern ground-cedar

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Facts

Northern ground-cedar is found in northern New England and across Canada. The Blackfoot had many uses for this clubmoss, including using the spores as an antiseptic on wounds and as a snuff to stop nosebleed. It is also used as a mordant in dye-making.

Habitat

Anthropogenic (man-made or disturbed habitats), forest edges, forests, 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
  • Vermont
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, with branches, those branches having further branches, and so on (tree-like)
Horizontal stem
the horizontal stem is on the surface of the ground
Leaf differences
the vegetative leaves within a node differ in size and shape
Teeth on leaf edges
the edges of the vegetative leaves have no teeth
Spore leaf length
2–3 mm
Leaf outline
  • the vegetative leaves are widest above the base, then taper narrowly towards the tip (lanceolate)
  • the vegetative leaves are long and very narrow (linear)
  • the vegetative leaves are roughly triangular, widest at the base where the leaf joins the stem
Show all characteristics

  • Clonal plantlets

    Gemma arrangement
    NA
    Gemma shape
    NA
    Gemma width
    0 mm

  • Leaves

    Leaf differences
    the vegetative leaves within a node differ in size and shape
    Leaf length
    0.7–7.3 mm
    Leaf orientation
    • the vegetative leaves are pressed against the stem
    • the vegetative leaves spread away from the stem
    Leaf outline
    • the vegetative leaves are widest above the base, then taper narrowly towards the tip (lanceolate)
    • the vegetative leaves are long and very narrow (linear)
    • the vegetative leaves are roughly triangular, widest at the base where the leaf joins the stem
    Leaf ranks
    4
    Leaf shape
    the vegetative leaves are short and scale-like
    Pores on leaves
    there are pores, but only on the underside of the vegetative leaves
    Spore leaf length
    2–3 mm
    Teeth on leaf edges
    the edges of the vegetative leaves have no teeth

  • Place

    Habitat
    terrestrial
    New England state
    • Maine
    • New Hampshire
    • Vermont
    Specific habitat
    • edges of forests
    • forests
    • man-made or disturbed habitats
    • meadows or fields

  • Spores or spore cones

    Cone base at stem
    the base of the spore-cone has a distinct stalk
    Cone stalk branching
    the stalks bearing the spore cones are branched, with pairs of branches
    Cone thickness
    0.4–0.7 mm
    Cone width
    2–3 mm
    Length of cone
    8.3–34 mm
    Number of cones
    1–4
    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 approximately rectangular 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, with branches, those branches having further branches, and so on (tree-like)
    Horizontal stem
    the horizontal stem is on the surface of the ground
    Horizontal stem thickness
    1.1–2.2 mm
    Stem height
    80–440 mm

Wetland status

Usually occurs in non-wetlands, but occasionally in wetlands. (Wetland indicator code: FACU)

In New England

Distribution

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

Conservation status

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

Vermont
extremely rare to rare (S-rank: S1S2)

From Flora Novae Angliae dichotomous key

1.  Diphasiastrum complanatum (L.) Holub N

northern ground-cedar. Diphasium complanatum (L.) Rothm.; Lycopodium complanatum L.; L. complanatum L. var. canadense Vict. • ME, NH, VT. Dry-mesic to mesic openings, edges, and forests, often in acid soils. This is the more northern sister species of Diphasiastrum digitatum.

1×2. Diphasiastrum complanatum × Diphasiastrum digitatum → Diphasiastrum ×‌verecundum A.V. Gilman is a rare ground-cedar hybrid 
of northern New England ( ME, NH, VT). The upright shoot branches are somewhat irregular (as in D. complanatum), but the stobilus stalk is stouter than in that species and often remains green after sporangium dehiscence. This hybrid may be more common than collections indicate, but the close similarity between its parents makes 
it difficult to detect.

1×4. Diphasiastrum complanatum × Diphasiastrum tristachyum → Diphasiastrum ×‌zeilleri (Rouy) Holub is a rare ground-cedar hybrid known 
from ME, NH, VT. It is intermediate between its parents in branch width, number of times 
the branches divide, and relative size of the trophophylls of the lower rank.

1×Diphasiastrum alpinum (L.) Holub. Diphasiastrum ×‌issleri (Rouy) Holub is 
a very rare ground-cedar hybrid in New England known only from northern ME. It 
generally resembles D. complanatum except that its lateral trophophylls usually roll under the branch (i.e., the branch margin is revolute) and the base of its strobilus 
is not distinct (i.e., there is a gradual transition from strobilus stalk trophophylls to strobilus sporophylls).

Native to North America?

Yes

Sometimes confused with

Diphasiastrum digitatum:
lateral branches of upright shoots lacking winter bud constrictions and strobili mostly 20-40 mm long, borne on relatively thicker stalks that remain green until after spore release (vs. D. complanatum, with lateral branches of upright shoots with winter bud constrictions and strobili mostly 10-25 mm tall, borne on very slender stalks that become stramineous prior to the release of the spores).

Synonyms

  • Diphasium complanatum (L.) Rothm.
  • Lycopodium complanatum L.
  • Lycopodium complanatum L. var. canadense Vict.

Family

Lycopodiaceae

Genus

Diphasiastrum