Ferns & Allies Notes

Question 1

Tracheophytes

Answer 1

Vascular plants - a monophylectic group among land plants.

Question 2

Vascular plant apomorphies

Answer 2

• lignified secondary cell walls, w/ pits (some)
• sclerenchyma tissue
• tracheary elements (xylem tissue)
• sieve elements (phloem tissue)
• endodermis
• independent, long-lived sporophyte generation

   AND, except for the earliest fossil lineages,

• sporophytic leaves associated with a stem to comprise a shoot system
• roots

Question 3

Vascular plant period of origin

Answer 3

Silurian Period, some 450 mya

Question 4

The earliest members of tracheophytes belong to three extinct groups, which are known only from fossils.

Answer 4

• rhyniophytes
• zosterophyllophytes
• trimerophytes

Question 5

Rhyinophyta characteristics

Answer 5

• seedless
• simple, dichotomously branched stems
• no true roots or leaves
• round or elongate terminal sporangia
• homosporous

Question 6

Cooksonia

Answer 6

The oldest known vascular plant. Its stem was ca. 6.5 cm tall, and its sporangia were round. It became extinct by the mid- Devonian period, ca. 390 mya.

Question 7

Rhynia

Answer 7

A marsh plant, came next, during the early Devonian (ca. 410-360 mya) . The upright stem was ca. 18 cm tall, ca. 3 mm thick, and dichotomously branched. It possessed a cuticle, was photosynthetic, and had stomata.

Question 8

Zosterophyllophyta characteristics

Answer 8

• seedless
• simple, dichotomously branched stems
• no true roots or leaves
• round or kidney-shaped lateral sporangia borne on short stalks
• homosporous
• probable ancestors of lycophytes

Question 9

Trimerophyta characteristics

Answer 9

• seedless
• complex, dichotomously branched stems
• no true roots or leaves
• elongate lateral sporangia borne on short stalks
• homosporous
• evolved from rhyniophytes
• ancestor of ferns and possibly horsetails

Question 10

Pteridophytes

Answer 10

• This group comprises the extant, seedless vascular plants. At one time, these plants, such as Lepidodendron, dominated the earth. This was especially true during the Carboniferous Period.
• Today, pteridophytes comprise over 13,000 living species. In North America, north of Mexico, there are about 400 species.

Question 11

Lycopodiophyta apomorphies

Answer 11

• endarch protoxylem of roots
• exarch protoxylem of stems
• lycophyll (microphyll) leaf type. This is a relatively small leaf that possesses only a single strand of vascular tissue. It is usually associated with stems that have protosteles. Leaf gaps are not produced by lycophylls.

Question 12

Family Lycopodiaceae characterics

Answer 12

• common names: club moss, ground pine, running cedar
• aboveground stems are dichotomously branched

• belowground stems (rhizomes) possess adventitious roots

• sporangia are associated with sporophylls
• sporophylls are often aggregated into a strobilus
• homosporous

* Lycopodium - common in North America. Certain species were collected for making Christmas wreaths, and the dry spores were once used as flash powder and condom lubricants.

Question 13

Family Selaginellaceae characteristics

Answer 13

• common name: spike moss
• aboveground stems are dichotomously branched
• belowground stems (rhizomes) possess adventitious roots

• leaves possess a ligule

• microsporangia are associated with microsporophylls, megasporangia are associated with megasporophylls
• sporophylls are often aggregated into a strobilus
• heterosporous

* most Selaginella sp. live in tropical regions

Question 14

Family Isoetaceae characteristics

Answer 14

• common name: quillwort
• belowground stems are short, erect, and cormlike; and possess adventitious roots
• leaves are long and quill-like, and each possesses a ligule

• microsporangia and megasporangia are sunken in the bases of the leaves

• heterosporous

* Isoetes - an emergant plant of shallow ponds.

Question 15

Euphyllophytes

Answer 15

• sister group of lycophytes

• comprises remaining tracheophytes (vascular
plants)

• 30-kilobase inversion in the large single-copy region of chloroplast DNA
• exarch protoxylem of roots
• euphyll (megaphyll) leaf type. This is a relatively large leaf that usually possesses several strands of vascular tissue, as well as a leaf gap.

Question 16

Monilophytes

Answer 16

• common name: ferns (in a broad sense)

• monophyletic group comprising members of
5 orders

• mesarch protoxylem of stems
• most members possess a stem vasculature known as a siphonolostele

Question 17

Steles

Answer 17

Another name for the vascular cylinder is the stele. There are several types of steles ranging from primitive to advanced.

Question 18

Protostele

Answer 18

• A protostele is the simplest and most primitive type of stele. It consists of a solid cylinder of vascular tissue in which the phloem either surrounds the xylem (haplostele = A, actinostele = B) or is interspersed within it (plectostele = C).
• Protosteles are found in most roots. In stems, protosteles are usually found in extinct vascular plants, psilophytes, and lyco

Question 19

Siphonostele

Answer 19

A siphonostele is characterized by having a pith surrounded by vascular tissue. The phloem tissue may be found only on the outside of the xylem (ectophloic = D) or on both sides (amphiphloic = E). A dictyostele (F) is characterized by a system of strands of vascular tissue around a pith.

Question 20

Eustele

Answer 20

A eustele (G) is also characterized by a system of strands of vascular tissue around a pith. An atactostele (H) is characterized by vascular tissue scattered throughout the pith. These two stele types are found in seed plants.

Question 21

What are the shared apomorphies of Ophioglossales and Psilotales?

Answer 21

• roots unbranched, root hairs absent
• gametophyte subterranean, mycorrhizal

Question 22

Order Ophioglossales

Answer 22

• common name: ophioglossoid ferns

• fronds are dimorphic, with a sterile segment
and a fertile segment

• eusporangium (large sporangium with wall comprising more than one cell layer; formed from more than one epidermal cell; may have 128-several thousand spores; no annulus)

Question 23

Family Ophioglossaceae

Answer 23

• common names: adder’s tongue, grape fern
• sporangia aggregated into an upright fertile region or spike
• homosporous

Question 24

Ophioglossum (adder’s tongue)

Answer 24

• several species in North America
• record for most chromosomes (n=621)!

Question 25

Order Psilotales

Answer 25

* common name: psilophytes * stems dichotomously branched * enations * lack true roots (probably lost) * absorptive rhizoids arise from rhizome * sporangia arranged in groups of 3's (synangia) * homosporous

Question 26

Family Psilotaceae

Answer 26

\* *Tmesipteris* (ca. 10 species) • Australia, New Zealand, Philippines, New Guinea • members have larger leaf-like appendages than Psilotum. \* *Psilotum* (2 species) * common name: whisk fern or whisk broom * found naturally in the warmer parts of the southeastern United States

Question 27

Order Equisetales

Answer 27

* common names: equisetophytes, spenophytes, horsetails, scouring rushes * homosporous (spores possess chloroplasts) * four major apomorphies * stems conspicuously jointed, ribbed, often hollow, unbranched or with whorls of branches * leaves greatly reduced to a whorl of scales forming a sheath at the nodes. * strobili terminal; sporangia attached to sporangiophores * spores with four elaters, which coil and uncoil in response to changes in humidity

Question 28

*Calamites *

Answer 28

An equisetophyte that took the form of a large tree and was widespread ca. 300 mya during the Carboniferous period. Much of our coal comes from the remains of this plant. * several species are native to N. America * rough silica- containing stems may have been used by settlers to clean pots and pans.

Question 29

Order Marattiales

Answer 29

* common name: marattioid ferns * large pinnate or bipinnate fronds that have circinate vernation (unrolling of the frond during development; produces a fiddlehead) * eusporangiate * polycyclic siphonostele

Question 30

Order Polypodiales

Answer 30

* common names: leptosporangiate ferns * leptoporangium (small sporangium with annulus; formed from one epidermal cell; may have 64-128 spores) * sporangia usually grouped into clusters know as sori * sori may be indusiate or exindusiate * false indusia are present in some groups * sporangia possess an annulus, which helps in spore dispersal

Question 31

Family Polypodiaceae

Answer 31

* common name: polypody * rhizomes creeping, covered with scales; leaves often simple though usually lobed * sporangia forming a mound-like sorus, exindusiate \* Polypodium (75 species) * common in the eastern United States * strobili have micro- & megasporophylls with micro- and megasporangia

Question 32

Family Osmundaceae

Answer 32

* common name: royal fern, cinnamon fern, interrupted fern * leaves pinnately compound, dimorphic, the fertile pinnae differentiated from the sterile pinnae; sporangia large \* *Osmunda* (14 species) - common in N. America

Question 33

Family Schizaeaceae

Answer 33

* common name: climbing fern * vines and grass-like tufted plants * leaves dimorphic, some produce sporangia, others do not \* *Lygodium* (60 species) - found in the eastern United States as far north as Michigan

Question 34

Family Pteridaceae

Answer 34

* common name: maidenhair fern * pinnae dichotomously veined * sori along the veins, or along the reflexed margins of the pinnae (false indusia) \* *Adiantum* (200 species) - found throughout much of the eastern United States

Question 35

Family Dennstaedtiaceae

Answer 35

* common name: bracken fern, hayscented fern * rhizome creeping; leaves large and divided * sori along leaf margin or on back of leaf \* Pteridium (1 species) - common name: bracken fern * found over much of the world * marginal sori covered by rolled-over leaf blade (false indusium)

Question 36

Family Aspleniaceae

Answer 36

* common name: spleenwort * sori round or elongate, indusia kidney- shaped or linear; spores surrounded by a wrinkled or winged sheath-like covering \* *Asplenium* - both temperate and tropical regions

Question 37

Family Dryopteridaceae

Answer 37

* common name: wood fern * sori borne on the veins or at the vein tips \* *Dryopteris* (150 species) - both temperate and tropical regions • marginal sori covered by kidney-shaped indusia \* *Onoclea* - sensitive fern • sori completely enclosed by leaf material

Question 38

Family Marsileaceae

Answer 38

* common name: water clover * aquatic; ground-level stolons produce the leaves, each leaf has two leaflets * sporocarps produced \* *Marsilea* (60 species) - water fern * microsporangia and megasporangia are in sori, which are in sporocarps (viable up to 30 years) * heterosporous (microspores and megaspores) * microsporangium has 32-64 microspores * megasporangium has 1 megaspore

Question 39

Family Salvineaceae

Answer 39

* common name: salvinia, water spangles * floating aquatics; leaves in whorls of three, two floating and simple, and one very divided and dangling, resembling a root * sporocarps produced \* *Salvinia* - mainly tropical America and Africa • each plant has two floating leaves and one dissected root-like submerged leaf

Question 40

Family Azollaceae

Answer 40

* common name: mosquito fern * floating aquatic; leaves in two rows, scale-like and overlapping, harboring cyanobacterium Anabaena azollae (nitrogen fixation) * sporocarps formed \* *Azolla* * often takes on a reddish or reddish green color * temperate and tropical areas