L5: Evolution and Diversity of Woody and Seed plants

Which of the following are true about Lignophytes?

• Lignophytes are also called woody plants or Lignophyta.

• They are a monophyletic lineage of

  euphyllous vascular plants that share derived features.

• One of the derived features are vascular cambium which gives

  rise to wood.

• Another is the cork cambium - which produces

  cork.

Growth of the vascular and cork cambia is called _________ because it initiates after the vertical extension of stems and roots due to cell expansion (primary growth).

• secondary growth

• primary growth

• tertiary growth

__________ is a sheath or hollow cylinder of cells that develops within the stems and roots as a continuous layer between the xylem and phloem in extant eustelic spermatophytes.

The cells of the vascular cambium divide mostly tangentially (parallel to a tangential plane), resulting initially in two concentric layers of cells

• True

• False

One of the layers remains as the vascular cambium and continues to divide indefinitely; the other layer eventually differentiates into either:

• secondary xylem or wood, if

  produced to the inside of the

  cambium.

• primary xylem or wood, if

  produced to the inside of the

  cambium.

• primary phloem, if produced to

  the outside

• secondary phloem, if produced to

  the outside of the cambium

Cells are produced both to the inside and outside of a continuously generated cambium are termed as ________.

________ is similar to a vascular cambium only it differentiates near the periphery of the stem or root axis.

The cork cambium and its derivatives constitute the ________ (referred to as

the outer bark).

The outermost layer of the periderm is the ____.

Cork cells contain a waxy polymer called _______ (similar to cutin) that is quite resistant to _____ ____.

• suberin, water loss

• cutin, water loss

• wax, water loss

• cuticle, water loss