Chapter 25: Seedless Plants

These flashcards cover key concepts, definitions, and adaptations related to seedless plants as noted in Chapter 25.

Algal Ancestry

Plants share a common ancestor with charophytes (green algae) in the archaeplastida supergroup of eukaryotes.

Multicellularity

A shared characteristic of Chlorophytes, Charophytes, and Plants.

Desiccation

The constant danger of drying out that land plants face.

Alternation of Generations

A life cycle in all land plants that exhibits a cycle between haploid (n) and diploid (2n) multicellular forms.

Haploid Spores

Spores produced by meiosis in land plants that are walled to protect from desiccation.

Apical Meristem

Continuously dividing cells in roots and shoots that allow plants to grow toward resources.

Waxy Cuticle

A protective layer on plant surfaces that prevents desiccation.

Bryophytes

Nonvascular, seedless plants that require water for reproduction and have three phyla: liverworts, hornworts, and mosses.

Sporophylls

Leaves modified to bear sporangia; essential for reproduction in seedless vascular plants.

Mycorrhizae

A mutualistic association between fungi and plant roots that aids in water and nutrient absorption.

Microphylls

Small, spine-shaped leaves with a single strand of vascular tissue, characteristic of Lycophytes.

Megaphylls

Leaves with a highly branched vascular system, found in most vascular plants.

Homospory

The production of one type of spore in most seedless vascular plants, leading to bisexual gametophytes.

Heterospory

The production of two distinct types of spores in seed plants and some seedless vascular plants, leading to different male and female gametophytes.

Ferns

The most widespread and diverse group of Monilophytes, characterized by large megaphylls and reproductive structures called sori.

Environmental Importance of Mosses

Mosses are indicators of environmental pollution and are important for soil conditioning and as renewable resources.