Botany 301 (UNIT 8)

Unit 8A

I belive in you!!!

What are lycophytes?

Seedless vascular plants with microphyll leaves and dichotomous branching.

What are the three living lycophyte families?

Lycopodiaceae, Selaginellaceae, and Isoetaceae.

Which extinct lycophyte family formed large trees?

Lepidodendraceae, which contributed to Carboniferous coal deposits.

What are microphylls?

Small leaves with a single unbranched vascular vein.

What is dichotomous branching?

When a growing stem or root divides into two branches.

What is a sporophyll?

A specialized leaf that bears a sporangium.

What is a sporangium?

A structure that produces spores through meiosis.

What is a strobilus?

A cone-like cluster of sporophylls bearing sporangia.

What is the dominant generation in lycophytes?

The diploid (2N) sporophyte.

Why do lycophytes need water for fertilization?

Their sperm must swim through water to reach the egg.

What do archegonia produce?

eggs

What do antheridia produce?

sperm

How are gametes produced in lycophytes?

By mitosis in the haploid gametophyte.

What are the three gametophyte nutritional modes?

Photosynthetic, mycoheterotrophic, or dependent on parent-provided resources.

What is homospory?

Production of one spore type, usually forming bisexual gametophytes.

What is heterospory?

Production of two spore types: microspores and megaspores.

What do microspores develop into?

Male gametophytes that produce sperm.

What do megaspores develop into?

Female gametophytes that produce eggs.

What is exosporic gametophyte development?

The gametophyte develops outside the spore wall.

What is endosporic gametophyte development?

The gametophyte develops within the spore wall.

. Which lycophyte family is homosporous?

Lycopodiaceae.

Which living lycophyte families are heterosporous?

Selaginellaceae and Isoetaceae.

What is a ligule, and which families have it?

A mucilage-secreting leaf structure in Selaginellaceae and Isoetaceae.

Which lycophyte families have secondary growth?

Isoetaceae and extinct Lepidodendraceae.

What is unusual about secondary growth in Isoetaceae?

A unifacial cambium produces mixed vascular tissue inward toward the corm.

UNIT 8 - part B

YOU GOT THISSSSSSSSS