BOT 14 LAB - EXERCISE 3 EVOLUTION OF VASCULAR TISSUES: FERNS AND ALLIES

1. recognize representatives of the cryptogams;

2. compare their spore-bearing structures;

3. distinguish different types of steles;

4. differentiate a megaphyll from a microphyll;

Provide the learning objectives.

xylem and phloem

One remarkable adaptation of plants to life on land is the evolution of vascular tissues, the ______________ and the ______________.

vascular plants; tracheophytes

Most of the land plants have vascular tissues and are known as _____________________ or ___________________.

stele; stele

Vascular tissues form the _____________ collective term for the central cylinder with other tissues inner to the cortex. The ______________ consists of the primary vascular system of the plant axis (stem) and its associated ground tissues.

stelar theory

Stele formation is best explained by the _______________, proposed by Van Tieghem and Douliot in 1886.

cryptogams

Essentially, the spore-bearing vascular plants (_______________) the ferns and fern allies.

Psilophyta, Lycophyta, and Sphenophyta; lower vascular plants; microphylls; homosporous

stele; uni-veined; sporophyte; gametophyte

The cryptogams, specifically divisions _____1______, _______1_______, and ______1______, are often considered the __________2___________ representing the earliest forms of tracheophytes due to the following features:

1) a simple but well differentiated __________;

2) ______________ lateral appendages called ______3______;

3) an erect, conspicuous, free-living ______________________;

4) an inconspicuous, subterranean, tuberous, but free-living ______________________;

5) mostly one type of spores within the sporangium (________5________).

Pterophyta

Ferns belong to the division ________________ other cryptogams, they are spore-bearing and mostly homosporous.

Ferns; exosporic

______________?

Their gametophytes are conspicuous although reduced, independent of the sporophyte, and can germinate outside of the spores (____________).

megaphylls

Unlike the rest of the spore-bearing plants, ferns have a more complex stele organization and possess photosynthetic leaves with a more intricate vascular system called _______________.

leaf traces; leaf gaps; higher vascular

Megaphylls are associated with ________________ and _________________ on the stem. These features have included them among the ________________ plants along with the gymnosperms and angiosperms.

Ferns

They also play as pioneers in ecological succession.

Division Psilophyta: Whiskferns or Forkferns

They are the least complex of all vascular plants primarily because they lack both roots and leaves.

enation

Division Psilophyta: Whiskferns or Forkferns

Attached to the upright stem are epidermal outgrowths called ________________.

rhizome; rhizoids

Division Psilophyta: Whiskferns or Forkferns

The plant has an underground stem, the ________, with ____________ for anchorage and water absorption.

synangium; sporangia; homosporous

In some branches, along the axils of the enations, are the yellow-colored __________, made up of three fused ___________. Each sporangium contains just one type of spores, thus, described as ___________.

Lycopodiopsida; Selaginellopsida; Isoetopsida

2. Division Lycophyta: Clubmosses, Spikeferns, and Quillworts

There are around 1,200 living species divided into three main classes: _____________ represented by Lycopodium; _____________ where Selaginella belongs; and _____________ represented by Isoetes.

Most species are tropical to subtropical commonly found in moist forests, either as ground dwellers or epiphytes.

Lycopodium: Clubmosses

Selaginella: Spikeferns

Isoetes: Quillworts

Lycopodium: _____________

Selaginella: _____________

Isoetes: _____________

heterophylly

Selaginella: Spikeferns

Examine the live specimen of Selaginella sp. Unlike Lycopodium, it has two types of microphylls: the large lateral ones and smaller middle rows.

This condition is known as ____________ or anisophylly.

rootstock

Obtain an herbarium specimen of I. philippinensis and observe it carefully. Its leaves are elongated and narrow with spoon-like bases arising from a corm-like base called the __________.

eusporangiate; leptosporangiate

Ferns maybe classified as either _______________ or _______________.

eusporangium; leptosporangium

A _____________ originates from a series of superficial parent cells or initials. Each develops a wall two or more cell layers thick (although at maturity, the inner wall layers may crush) and a high number of spores.

On the other hand, a _____________ originates from a single cell initial which first produces a stalk and then a capsule. Each gives rise to a relatively small number of spores.