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Spinulum annotinum — bristly clubmoss, common interrupted-clubmoss

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Facts

Common interrupted-clubmoss is so called because each year's growth is noted by an interruption or constriction on the stem. It is also sometimes called bristly clubmoss because it is prickly to the touch.

Habitat

Alpine or subalpine zones, forest edges, forests

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
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Rhode Island
  • 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, 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 tiny teeth
Spore leaf length
3–4.4 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 widest near the tip, but otherwise narrow and tapering (oblanceolate)
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
    5.2–9.8 mm
    Leaf orientation
    • the vegetative leaves curve outwards and downwards from the main stem
    • the vegetative leaves spread slightly away from the stem, at a steep angle
    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 widest near the tip, but otherwise narrow and tapering (oblanceolate)
    Leaf ranks
    10 or 11
    Leaf shape
    the vegetative leaves are short and scale-like
    Pores on leaves
    • there are pores on both sides of the vegetative leaves
    • there are pores, but only on the underside of the vegetative leaves
    Spore leaf length
    3–4.4 mm
    Teeth on leaf edges
    the edges of the vegetative leaves have tiny teeth

  • Place

    Habitat
    terrestrial
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Rhode Island
    • Vermont
    Specific habitat
    • alpine or subalpine zones
    • edges of forests
    • forests

  • Spores or spore cones

    Cone base at stem
    the base of the spore-cone has a distinct stalk
    Cone stalk branching
    NA
    Cone thickness
    0 mm
    Cone width
    6–7 mm
    Length of cone
    15–43 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 have tiny 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 similar in size to 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
    1.5–2.2 mm
    Stem height
    150–280 mm

Wetland status

Occurs in wetlands or non-wetlands. (Wetland indicator code: FAC)

In New England

Distribution

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

Conservation status

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

Massachusetts
widespread (S-rank: S5)
Rhode Island
extremely rare (S-rank: S1), state endangered (code: SE)

From Flora Novae Angliae dichotomous key

1.  Spinulum annotinum (L.) A. Haines N

common interrupted-clubmoss. Lycopodium annotinum L.; L. annotinum L. var. acrifolium Fern. • CT, MA, ME, NH, RI, VT; nearly throughout, but rare in RI. Forests and forest edges, including boreal and subalpine areas, infrequently above tree line at the edges of krummholz islands.

1×2. Spinulum annotinum × Spinulum canadense → This uncommon interrupted-clubmoss hybrid is located most frequently where the parent species are sympatric (e.g., on the higher mountains of ME and NH). It can be recognized by intermediate leaf length and dentition between the parental clones and shows 1–15 stomates per ½ adaxial surface on trophophylls from the middle of seasonal growth (compared with 25–53 per ½ adaxial surface in Spinulum canadense).

Native to North America?

Yes

Sometimes confused with

Spinulum canadense:
leaves near the middle of seasonal growth 3-5.9 mm long and obscurely toothed to entire, and spore cones mostly 8-17 mm tall (vs. S. annotinum, with leaves near the middle of seasonal growth 5.2-9.8 mm long and obscurely to evidently toothed, and spore cones mostly 17-43 mm tall).
Huperzia lucidula:
plants with specialized branches that produce gemmae and lacking spore cones, the spore-bearing leaves in alternating zones with the vegetative leaves (vs. S. annotinum, with plants lacking specialized branches that produce gemmae, and with spore cones at the apex of branches on mature plants).

Synonyms

  • Lycopodium annotinum L. var. acrifolium Fern.

Family

Lycopodiaceae

Genus

Spinulum