Polypodiaceae (Ferns)

Question 1

What to look at when attempting to ID a fern

Answer 1

• fronds
• turn it over and look at reproductive structures
• look at frond stalk-taking note of color and texture

Question 2

Frond

Answer 2

• Consists of a stalk with a green, leaf-like growth emerging from it
  
  • Subdivided into multiple leaf-like growths
  • Pinna-each large blade division is called a “pinna”, plural “pinnae” (pin-knee)

Question 3

Terms associated with Pinna

Answer 3

• Pinna-each large blade division is called a “pinna”, plural “pinnae” (pin-knee)
• Pinnules- the lobes the pinnae are divided into
• Lobes- further division of the pinnules
• fronds that are divided again and again are called finely-cut
  
  • the more the leaf-like material is divided, the more feathery it will look

Question 4

Fern Reproductivity

Answer 4

• Do not produce seeds, but spores
• Sori (sore-eye)/Sorus-house the microscopic spores while they are developing
• Sometimes easily seen on underside of frond. Other times the presence of a sori just seems to change the color, texture, and shape of the frond

Question 5

Location of Sori

Answer 5

• Some ferns produce sterile fronds (fronds without sori), while also producing one or more fertile fronds (with sori)
• Other ferns consist entirely of fertile fronds
• In others, the sori only emerge from some of the pinnae, while they are absent from the rest of the pinnae

Question 6

The Stalk

Answer 6

• Stipe- the part of the stalk from the ground to the beginning of the frond’s leafy area
• Rachis- the portion of the stalk in which the leafy material is attached

Question 7

Spleenworts

Answer 7

• Do not have spherical sori
• Each sorus is similar to the shape of a spleen/kernel of rice
  
  • elongated, oval shaped sori

Question 8

Answer 8

Christmas Fern

• ”bump” on the pinna near the stalk
• imagine Santa is the bump and he is sitting on a sled
• Spores only develop on top portion of frond-the fertile pinnae curl up as the spores develop
• Sori underneath pinna are not distinctly visible but they cause the entire underside to turn brown

Question 9

Answer 9

Christmas fern

• Spores only develop on top portion of frond-the fertile pinnae curl up as the spores develop
• Sori underneath pinna are not distinctly visible but they cause the entire underside to turn brown

Question 10

Why are they called “Christmas” ferns?

Answer 10

People in the 1800s used their evergreen fronds to decorate their homes for Christmas

Question 11

Answer 11

Maidenhair Wood Fern

• long, black stipe the divides into two rachis, which bend in a semi-circle towards eachother
• reddish fiddleheads with wirey hairs
• very slender stipes
• notched or lobed fan-shaped pinnae with very short stalks
• spores are found along the edge on the underside of the pinnae, linear to oblong sachi

Question 12

Answer 12

Maidenhair Spleenwort

• very short, almost invisible stipe
• often grows right out of rock, particularly limestone
• pinnae are shorter than maidenhair wood fern, nearly as wide as long
• Pinnae edges scalloped
• State threatened in MN

Question 13

Answer 13

Lady Fern

• reddish-wine colored stalk
• pinnae tend to be widely spaced on its rachis

Question 14

Answer 14

Maidenhair Wood Fern

• very slender stipes
• notched or lobed fan-shaped pinnae with very short stalks
• spores are found along the edge on the underside of the pinnae, linear to oblong sachi

Question 15

Answer 15

Lady fern

• Leaflets have rounded or pointed lobes and tips, rounded or pointed (but not bristly) teeth
• forked veins that do not typically extend quite all the way to the leaflet edge

Question 16

Answer 16

Lady Fern

• The sori (cluster of spores) develops on the back of the leaf blade in summer and is typically curved to hook-shaped

Question 17

Answer 17

Lady Fern

• The slender stem is covered in dark brown scales.

Question 18

Answer 18

Maidenhair Wood fern

• reddish-purplish fiddleheads with white wirey hairs

Question 19

Answer 19

Christmas fern

• Fiddleheads are light green and densely covered in silvery scales.

Question 20

Answer 20

Cinnamon fern

• closely resembles Interrupted fern. (ULI-unlike inter.)
• no sori on underside of pinnae, ULI, instead they’re all on a central fertile frond that shoot up
• White fuzz present where pinna attaches to rachis, ULI

Question 21

Answer 21

Cinnamon fern

• closely resembles Interrupted fern. (ULI-unlike inter.)
• no sori on underside of pinnae, ULI, instead they’re all on a central fertile frond that shoot up
• White fuzz present where pinna attaches to rachis, ULI

Question 22

Answer 22

Cinnamon fern

• closely resembles Interrupted fern. (ULI-unlike inter.)
• no sori on underside of pinnae, ULI, instead they’re all on a central fertile frond that shoot up
• White fuzz present where pinna attaches to rachis, ULI

Question 23

Answer 23

Cinnamon fern

• Fiddlehead-As the fern emerges from the ground in early spring it is covered in a light brownish-colored wool but it is quickly lost.
• Similar to Interrupted fern

Question 24

Answer 24

Interrupted fern

• The sterile leaves grow arching in a circular clump with the fertile leaf (if present) growing more erect in the center.

Question 25

Answer 25

**Interrupted fern** * The capsules are initially dark green but turn dark brown with maturity. After releasing the spores, the capsules whither away leaving a large gap (i.e. “interruption”) in the middle of the leaf.

Question 26

Answer 26

**Interrupted fern** * no white pubescens where the pinna attaches to the rachis, unlike the cinnamon fern * no sachi on the underside, like cinnamon fern

Question 27

Answer 27

**Interrupted fern** * Fiddlehead- As the fern emerges in the spring it is covered in a light wool but it is quickly lost.

Question 28

Answer 28

**Ostrich fern** * Sterile and fertile fronds * sterile pinna taper abruptly toward their tips, while toward their bases the pinna become very small (less than 1" long — makes them easily identifiable (rare trait) * Pinnules of the sterile leaves are relatively short (2-12" in length), light green to brown, and relatively stout

Question 29

Answer 29

**Ostrich fern** * Sterile and fertile fronds * sterile pinna taper abruptly toward their tips, while toward their bases the pinna become very small (less than 1" long — makes them easily identifiable (rare trait) * Pinnules of the sterile leaves are relatively short (2-12" in length), light green to brown, and relatively stout

Question 30

Answer 30

**Ostrich fern** * Ostrich Fern has at least 1 spike 20 to 50 inches tall growing in the center of the leaf clump. 25 or more pairs of hard tubular-shaped "pods" contain the spores in somewhat bead-like structures. These fertile fronds are initially green but turn dark brown with maturity and persist through the winter, releasing spores the following spring before dying back.

Question 31

Answer 31

**Ostrich fern** * Veins are straight, not forked, in a chevron pattern most easily seen on the underside. The leaflet midrib may be covered to varying degrees in short hairs.

Question 32

Answer 32

**Sensitive fern** * Deciduous fronds die at first site of frost (sensitive) * Bright green sterile fronds that run along rachis * Pinnae are widely spaces along rachis * Upper pinnae have smoother edges while lower are deeply lobed/wavey

Question 33

Answer 33

**Sensitive fern** * 5 to 11 pairs of branches contain the spores in bead-like structures tightly packed along a branch. These fertile fronds turn brownish black at maturity and persist through winter, releasing the spores the following year.