lecture 8- hornworts, liverworts + mosses

Question 1

Name two apomorphies of the liverworts.

Answer 1

• gametophyte leafy (in some)
• elaters in sporangium
• oil bodies

Question 2

What are the two major morphological forms of liverworts? Which is likely ancestral?

Answer 2

thalloid and leafy:
* Thalloid* Likely the ancestral form

Question 3

What are gemmae and gemma cups?

Answer 3

• Pores in the upper surface of
  the thallus function in gas
  exchange
• Some thalloid liverworts,
  (e.g., Marchantia) have
  specialized gemma cups,
  which contain propagules
  called gemmae -vegetative
  (asexual) reproduction

Question 4

What is an antheridiophore? an archegoniophore? what plants do they occur in

Answer 4

• Liverworts have antheridia and
  archegonia that develop on the
  gametophyte
  Antheridiophore is the stalk like structure (gametophore) that bears antheridia i.e male sex organs. Archegoniophore is a stalk like structure on which archegonium i,e female sex organs are borne

Question 5

What land plant groups possess stomates?

Answer 5

Hornworts

Question 6

Describe the structural makeup and function of a stomate

Answer 6

• Specialized epidermal cells
• Two chloroplast-containing cells, (guard cells) which, by changes
  in turgor pressure, can increase or decrease the size of the
  opening between them (stoma)
• A waxy, water-resistant substance, functions to seal the stoma

Question 7

How do the hornworts differ from the liverworts?

Answer 7

sporophyte of hornworts is elongate,
cylindrical, and photosynthetic
* Sporophyte has indeterminate
growth: basal, intercalary
meristem - apomorphy for the
hornworts

Question 8

Name major apomorphies either shared by the mosses alone or possibly shared by the
mosses plus vascular plants

Answer 8

apomorphies
with the vascular plants – e.g.,
elongate, aerial sporophyte axis,

Question 9

What is a calyptra, stipe, operculum, peristome tooth?

Answer 9

operculum or calyptra is a cap-like structure in some flowering plants, mosses, and fungi. It is a covering, hood or lid
calyptra may function in protecting the
young sporophyte apex
a usually short stalk of a plant, alga, or fungus: such as. : the stem supporting the cap of a fungus
One or two rings of tooth-like appendages surround the capsule opening of mosses known as peristomes. The teeth unfold under dry conditions to disperse spores gradually

Question 10

What feature of the leaf anatomy of peat moss enables the leaves to absorb and retain
water?

Answer 10

Hyaline cells (large, unalive, porous)