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• Botrychium virginianum

Botrychium virginianum — rattlesnake fern

Facts

Rattlesnake fern is the most widespread member of the genus (Botrychium) in North America and the largest and most common species in New England. The tapered tip of the fertile blade is said to resemble a rattlesnake tail.

Habitat

Forests

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 dramatically different from the sterile fronds

• Leaves

  Features of leaves

  there are no special features on the leaves

  Leaf blade length

  4–30 cm

  Leaf blade shape

  the leaf blades are roughly triangular

  Leaf blade tip shape

  the tip of the leaf blade is a sharp point (acute)

  Leaf blade width

  At least 4 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

  • green
  • red or red-brown to purple or black
  • yellow to brown

  Leaf stalk hairs

  the leaf stalk has hairs

  Leaf stalk length

  70–350 mm

  Leaf stalk relative length

  the leaf stalk is more than three quarters as long as the blade

  Leaf stalk scale location

  there are no scales on the leaf stalk

  Leaf stalk scales

  there are no scales on the leaf stalk

  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 go all the way to 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
  • the bottom leaflets are at least one and a half times as long as the leaflets from the middle of the frond

  Leaflet stalks

  • the leaflets are stalked
  • the leaflets do not have stalks

  Lobe or leaflet length

  23–215 mm

  Lobe or leaflet pairs

  5–24

  Lobe or leaflet shape

  the lobe or leaflet is widest below the middle and tapering at both ends; lance-shaped

  Lobe or leaflet width

  13–199 mm

  Plant growth form

  the leaves grow on a stalk that also holds the sporophore, or spore-bearing leaf

  final leaf segment margin

  the topmost lobe or leaflet of the leaf blade has an edge with teeth

• Place

  Habitat

  terrestrial

  New England state

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

  Specific habitat

  forests

• Spores or spore cones

  Sorus features

  there are no special features on the sorus

  Sorus shape

  there are no sori, or they are concealed in leaf segments or hardened, capsule-like structures derived from a modified leaflet

  Sporangia location

  the spores are formed on a stalk (sporangiophore)

  Sporangium type

  the spores are enclosed in a hardened, capsule-like structure (sporocarp)

  Spore forms

  there is only one type of spore present

Wetland status

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

New England distribution and conservation status

From the dichotomous key of Flora Novae Angliae