BIOL 108 - Topic 15: Seedless Vascular Plants

Presence of Vascular Tissues (Shared, Derived Characteristics of Vascular Plants)

Tissues that provide rigidity for vertical growth and transports and distributed water and nutrients throughout the plants.

• xylem and phloem

• develops exclusively in the sporophytes of vascular plants

Sporophytes (Shared, Derived Characteristics of Vascular Plants)

The dominant part of the vascular plant life cycle.

• 2n

• do not continuously rely on gametophytes for nutrients

• dominant in size, complexity, and longevity

True Roots and Leaves (Shared, Derived Characteristics of Vascular Plants)

Complex, multicellular structures.

True roots:

• anchor and stabilize vascular sporophytes

• facilitates absorption and distribution of water and nutrients from the soil

• likely evolved from subterranean stems

True leaves:

• increases surface area of sporophytes for solar energy used in photosynthesis

Microphylls (Characteristics of Extant Vascular Plants)

Small leaves with single veins that likely evolved as an outgrowth of stems

• common in lycophytes

Megaphylls (Characteristics of Extant Vascular Plants)

Large leaves with highly branched vascular systems that likely evolved from webbing between flattened branches.

Sporophylls (Characteristics of Extant Vascular Plants)

Modified leaves bearing sporangia

• Sori

• Strobili

Sori (Sporophylls)

Clusters of sporangia on the undersides of sporophylls.

• Ex, ferns

Strobili (Sporophylls)

Cone-like structures formed by grouping of sporophylls.

• Ex, lycophytes

Homosporous (Characteristics of Extant Vascular Plants)

A characteristic of vascular plants where they have a single type of spore that develops into bisexual gametophytes.

• most seedless vascular plants

Heterosporous (Characteristics of Extant Vascular Plants)

A characteristic of vascular plants where they have two types of spores.

• megaspores that develop into female gametophytes

• microspores that develop into male gametophytes

• all seed plants, some seedless vascular plants

Flagellated Sperms (Characteristics of Extant Vascular Plants)

A shared feature with byrophytes where water is required for the flagellated sperms to fertilize eggs in archegonia.

• seedless vascular plants

Phylum Lycophata (Seedless Vascular Plants)

An ancient division of seedless vascular plants that once dominated Carboniferous swamps.

• club mosses, pike mosses, quillworts

• presence of microphyll leaves and strobili containing sporangia

• reproduction via spores instead of seed

Phylum Monilophyta (Seedless Vascular Plants)

A diverse group of seedless vascular plants.

• ferns

• most diverse in tropical regions but also thrive in temperate forests

• presence of megaphylls leaves

• sporangia with spring-like structures