Psilotum (Whisk Ferns)

Question 1

List three features of Psilotum.

Answer 1

1) Herbaceous
2) Dichotomously branched
3) Approximately 2 feet in height.

Question 2

Does Psilotum have roots & leaves?

Answer 2

No.

Psilotum lacks both roots & leaves.

Question 3

Does Psilotum contain vascular tissue?

Answer 3

Yes.

Axes (erect & rhizomes) contain vascular tissue.

Question 4

Describe the erect axes in Psilotum.

Answer 4

Bear small leaf-like appendages (called bracts or prophylls) that have no vascular tissue (i.e. not true leaves).

Question 5

What type of stele does Psilotum have?

Answer 5

Protoactinostele or siphonostele.

Question 6

What does the stele consist of?

Answer 6

1) Center of stele consists of thick-walled sclerenchyma cells.
2) Primary xylem is surrounded by primary phloem.

Question 7

What is a Protostele? Siphonostele?

Answer 7

1) Protostele - if sclerenchyma is considered part of primary xylem.
2) Siphonostele - if sclerenchyma is considered a pith.

Question 8

What is the stele bounded by?

Answer 8

Bounded externally by cortex tissue which consists of (from inside to outside):

1) Endodermis
2) Parenchyma cells
3) Sclerenchyma cells
4) Chlorenchyma

Question 9

What is the axes bounded by?

Answer 9

Bounded externally by cutinised epidermis, with stomata & guard cells in erect axes.

Question 10

What do surface cells of rhizome produce?

Answer 10

May produce multicellular rhizoids.

Question 11

What habitats is Psilotum found in?

Answer 11

1) Tropical & sub-tropical areas.
2) On soil
3) Can live far away from water.