Seedless vascular plants

Question 1

What are the four kinds of seedless vascular plants?

Answer 1

• club moss, horsetail, whisk ferns, ferns

Question 2

Describe the meristems of seedless vascular plants

Answer 2

• two apical meristems: root and shoot

primary meristem: protoderm (dermal), pro cambium (true xylem and true phloem), ground tissue (parenchyma, sclerenchyma, collenchyma)

Question 3

What are the two kinds of plant forms?

Answer 3

• megaphylls: multiple veins (one fern from is mega)
• micropyles: individual veins in each leaf

Question 4

Describe the generations in seedless vascular plants

Answer 4

• both are independent at maturity (sporophyte dominant, dependant on gametophyte when young but then independent)
• sporophytes are larger than gametophytes

Question 5

Describe the seedless vascular plant lifecycle

Answer 5

• gametophytes –> antheridia and archegonia –> fertilization = embryo –> sporophyte –> sporangia –> spore mother cells (meiosis) –> tetrads of spores –> spores –> gametophytes

Question 6

Why is heterospory important? Is it common in seedless vascular plants?

Answer 6

• It is RARE in seedless vascular plants, but it is an important precursor for seed and pollen production

Question 7

When did seedless vascular plants dominate? What were the 3 most important phyla during this period?

Answer 7

• during the Devonian period 350 million years ago
• rhinophyta, zosterophyllaphyta, trimerophytophyta
  (no living representatives!!!)

Question 8

How did early vascular plants photosynthesize?

Answer 8

• they had photosynthetic branches

Question 9

What are the two phyla living seedless vascular plants are classified into ?

Answer 9

• lycophytes (club moss, spike moss, quillworts)
• monilophyta (horse tail, tropical ferns, true ferns, whisk ferns)

Question 10

Describe the difference between modern lycophytes and Devonian lycophytes

Answer 10

• modern lycophytes small herbaceous,
  Devonian period ones were huge (carboniferous coal swamp style)

–> all lycophytes are microphyllic

Question 11

Which lycophytes are homosporous? heterosporous?

Answer 11

• club moss: homosporous
• spike moss: heterosporous
• quillworts: heterosporous

Question 12

Describe stobilus, sporophytes, and sporangia

Answer 12

Sporophylls and Strobili
–. sporophyte

Question 13

Are lycophytes mega-hulls or microphylls ??

Answer 13

• all lycophytes are microphyllic

Question 14

Describe the life cycle of the selaginella (spike moss)

Answer 14

• two sporphylls
• dimorphic constituion
• ligule: small lead for protection of sporangium
• hundreds of microspores, 4 megaspores
• archegonia protrudes, remaining megagametophyte development occurs within the spore wall
• water required for reproduction, shed nearby for easy fertilization
• endoscopic:

Question 15

What plant species is known as the resurrection plant?

Answer 15

• selaginella lepidophylla

Question 16

What are the four species in the monilophyta? Are they homosporous or heterosporous?

Answer 16

• psilotopsida (whisk ferns) : homosporous
• marratopsida: small group of tropical ferns
• polypodiopsida: true ferns - mostly homosporous except for water plants (heterosporous)
• equistopsida: horsetail: homosporous

Question 17

Describe the sub groups of psilotopsida

Answer 17

• two orders of homosporous ferns: ophioglossales (borthychum , ophioglossum) and Psiolates (tmesipteris and psilotum (whisk fern))

Question 18

Describe the psilotales

Answer 18

• one group of the psilotopsida
• two living genera: psilotim and tmesipteris
• tmesipteris grows as an epiphyte: grown on other stuff
• psilotum lacks true roots, has nations instead of leaves
• homosprous, bisexual gametophytes
  -gametophyte small underground structure (_1cm)
• dichotomous branching

Question 19

Describe polypodiopsida

Answer 19

• the true ferns
• most common ferns in this group (~10,500 species)
• most homosporous
• leaves are megaphylls
• sporangia occur on lower surface of leaves (need water)

Question 20

What are fiddleheads?

Answer 20

• young fern megaphylls emerging from gametophtue
• one of the only parts of the plants that is edible, much else is poisonous

Question 21

What are the reproductive structures of polypodiopsida?

Answer 21

• Sori: reproductive structures on the sporophyte of the fern head
• sorus have sporangia
• large yellow spots, have a protective covering called an indusium (sporophyte and the indusium are the sorus)

Question 22

What is the antheridiogen?

Answer 22

• a hormone released (especially by bisexual plants) for surrounding gametophytes to produce more antheridia and encourage cross fertilization

Question 23

How do ferns ensure spore dispersal?

Answer 23

• spores have a layer of thickened cells on the back called an annulus
• when it dries, the head catapults the spores around

Question 24

What is special about water ferns of the polypodiopsida?

Answer 24

• they are heterosporous!
• they have trichomes: small hair from above ground epidermal cells that help absorb huge amounts of oil into trichomes body

Question 25

Describe the number of spores produced and how the spores stay protected in polypodiopsida

Answer 25

- 1 2N can make 4 n haploid spores through meiosis - spore walls have sporopollenin which protects the plant from desiccation - when conditions are right the sporopollenin disintegrates and reproduction can occur