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Dryopteris carthusiana — spinulose wood fern

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Facts

Spinulose wood fern, like several other wood ferns (Dryopteris), is of hybrid origin, originally sterile and then becoming fertile after chromosome doubling. What makes this species unusual is that one of its parents can only be inferred. That is, it is no longer extant, possibly having become extinct during the most recent glaciation. It may form hybrids with five other wood fern (Dryopteris) species in New England.

Habitat

Forests, shores of rivers or lakes

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
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
  • Vermont
Leaf divisions
  • the leaf blade is three times compound (divided into leaflets, which are further divided into leaflets, which are further divided into leaflets), or more
  • the leaf blade is twice compound (divided into leaflets, which are further divided into leaflets)
Plant growth form
the leaves grow from a rhizome growing at or below the ground
Spore-bearing leaflets
the spore-bearing fronds are similar in size and shape to the sterile fronds
Sorus shape
the sori are circular or kidney-shaped
Leaf stalk scales
the leaf stalk has scales
Leaf stalk hairs
there are no hairs on the leaf stalk
Leaf blade length
10–60 cm
Leaf vein tips
the veins end in small round expanded areas, and do not reach the edge of the leaf blade
Show all characteristics

  • Growth form

    Life form
    the plant is herbaceous and terrestrial
    Life stage
    the plant is visible as a typical leaf-bearing fern (sporophyte)
    Spore-bearing leaflets
    the spore-bearing fronds are similar in size and shape to the sterile fronds

  • Leaves

    Features of leaves
    there are no special features on the leaves
    Leaf blade length
    10–60 cm
    Leaf blade shape
    • the leaf blades are widest above the base, then taper broadly towards the tip (ovate)
    • the leaf blades are widest above the base, then taper narrowly towards the tip (lanceolate)
    Leaf blade tip shape
    the tip of the leaf blade is a sharp point (acute)
    Leaf blade width
    At least 6 cm
    Leaf divisions
    • the leaf blade is three times compound (divided into leaflets, which are further divided into leaflets, which are further divided into leaflets), or more
    • the leaf blade is twice compound (divided into leaflets, which are further divided into leaflets)
    Leaf lifespan
    the leaves drop off in winter
    Leaf stalk color
    yellow to brown
    Leaf stalk hairs
    there are no hairs on the leaf stalk
    Leaf stalk length
    60–450 mm
    Leaf stalk relative length
    • the leaf stalk is more than a quarter, but less than three quarters as long as the blade
    • the leaf stalk is up to a quarter as long as the blade
    Leaf stalk scale location
    • the scales are present on both the lower and upper halves of the leaf stalk
    • the scales are present only on the lower half of the leaf stalk
    Leaf stalk scales
    the leaf stalk has scales
    Leaf stalk vessels
    3 to 9 bundles
    Leaf vein branching
    the secondary veins of the leaf blade branch dichotomously (two equal branches at each branch point)
    Leaf vein tips
    the veins end in small round expanded areas, and do not reach the edge of the leaf blade
    Leaflet relative size
    the bottom leaflets are about half as long as, to slightly longer than, the leaflets from the middle of the frond
    Leaflet stalks
    the leaflets are stalked
    Lobe or leaflet length
    22–150 mm
    Lobe or leaflet pairs
    10–30
    Lobe or leaflet shape
    • the lobe or leaflet is rectangular but with rounded ends (oblong)
    • the lobe or leaflet is widest below the middle and tapering at both ends; lance-shaped
    Lobe or leaflet width
    10–84 mm
    Plant growth form
    the leaves grow from a rhizome growing at or below the ground
    final leaf segment margin
    the topmost lobe or leaflet of the leaf blade has an edge with teeth tipped with bristles

  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    • Vermont
    Specific habitat
    • forests
    • shores of rivers or lakes

  • Spores or spore cones

    Sorus features
    there are no special features on the sorus
    Sorus shape
    the sori are circular or kidney-shaped
    Sporangia location
    the spores are clustered on sori on the lower surface of the leaf blade
    Sporangium type
    the sporangia are opaque without an annulus and usually without a stalk (leptosporangiate)
    Spore forms
    there is only one type of spore present

Wetland status

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

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
unranked (S-rank: SNR)

From Flora Novae Angliae dichotomous key

2.  Dryopteris carthusiana (Vill.) H.P. Fuchs N

spinulose wood fern. Dryopteris austriaca (Jacq.) Woynar ex Schinz & Thellung var. spinulosa (O.F. Muell.) Fiori; D. spinulosa (O.F. Muell.) Watt • CT, MA, ME, NH, RI, VT. Mesic to hydric forests and stream shores.

2×3. Dryopteris carthusiana × Dryopteris clintoniana → Dryopteris ×‌benedictii Wherry is a rare wood fern hybrid known from CT, MA, NH, VT. It shows leaf blades mostly 2.5 times divided near base with ± parallel margins and an abrupt apical taper, no stipitate glands on the indusia, and sori positioned midway between the midvein and margin.

2×4. Dryopteris carthusiana × Dryopteris cristata → Dryopteris ×‌uliginosa (A. Braun ex Dowell) Druce is an uncommon wood fern hybrid known from CT, MA, ME, NH, VT. It shows somewhat narrow leaf blades (relative to length) mostly 2.5 times divided at base with triangular lower leaflets, no stipitate glands on the indusia, and sori positioned midway between the midvein and margin. Very similar to D. ×boottii, but that hybrid would show stipitate glands on the indusia.

2×7. Dryopteris carthusiana × Dryopteris goldiana → Dryopteris ×‌correllii W.H. Wagner is an extremely rare wood fern hybrid 
known from VT. It has an oblong leaf blade mostly divided 2.5 times near base with an abruptly tapered apex, dark brown scales on the petiole, no glands on the indusia, 
and sori positioned midway between the midvein and margin.

2×8. Dryopteris carthusiana × Dryopteris intermedia → Dryopteris ×‌triploidea Wherry is an uncommon wood fern hybrid known 
from CT, MA, ME, NH, RI, VT. It shows long, often outward pointed, basiscopic leafules on the lower leaflets and ± forward-curving teeth (similar to D. carthusiana), but the 
indusia (and often the rachis and costae) have stipitate glands, and the leaf blades 
are somewhat evergreen.

2×9. Dryopteris carthusiana × Dryopteris marginalis → Dryopteris ×‌pittsfordensis Slosson is a very rare wood fern hybrid known 
from CT, MA, VT. It shows sori positioned closer to the margin than the midrib of the ultimate segments, and it has fairly dense scales at the base of the petiole (as do other D. marginalis hybrids). However, the hybrid is very similar to D. carthusiana in regard 
to overall leaf blade outline, division of segments, and margin of segments (serrate 
vs. entire or crenate in D. marginalis). The leaf blade texture is also thicker than in 
 D. carthusiana, lending a semi-evergreen habit to the blade.

Native to North America?

Yes

Sometimes confused with

Dryopteris campyloptera:
first pair of leafules on lowest leaflet obviously offset from one another, and mainly occuring in the mountains and more northern areas (vs. D. carthusiana, with first pair of leafules on lowest leaflet nearly opposite one another and wide-spread occurrence, mostly at low elevation). Dryopteris intermedia: first lower leafule on lower leaflet as long as or longer than adjacent leafule and rachis and midrib of leaflets and leafules without stipitate glands (vs. first lower leafule on lower leaflet shorter than the adjacent leafule and rachis and midrib of leaflets and leafules with stipitate glands).

Synonyms

  • Dryopteris austriaca (Jacq.) Woynar ex Schinz & Thellung var. spinulosa (O.F. Muell.) Fiori
  • Dryopteris spinulosa (O.F. Muell.) Watt

Family

Dryopteridaceae

Genus

Dryopteris