Seed Plants I: Seed Plants W/O flowers

Concepts

Division Pteridospermophyta

Division Ginkgophyta

Division Coniferophyta

Division Progymnospermophyta

Division Cycadeoidophyta #

Division Gnetophyta

Division Cycadophyta # #

Archaeopteridales

Evolution of Seeds

Aneurophytales

Lignophytes

Progymnosperms

Now extinct

Some gave rise to later trees

Cycads

Other Gymnosperms

Conifers

Also developed megaphyllous leaves

Evolution of vascular cambium

Capable of undergoing radial division

unlimited growth potential

Capable of producing

secondary xylem

secondary phloem

Contains more relictual pro gymnosperms

Protopteridium

Proteokalon

Aneurophyton

Tetraxylopteris

Vary in stature

contain vascular cambium/secondary growth

Primary xylem was protostele

similar to rhyniophytes/trimerophytes

abundant wood and primary xylem

Stems of archaeopteris

siphonostele

pith surrounded by

ring of primary xylem bundles

Similar to modern conifers and dicots

Integument

Pollen Chamber

layer of tissue that surrounds the megasporangium

Micropyle

a hole in the integument

permitted the sperm cells to get to the egg

After the megaspore had developed to Megagamterophyte

Produced an egg

also known as a holding area

Place where microspores settled

Fused together and to the megasporangium

space at top of megasporangium

Seed Ferns

Classified by 3 division

Cycadophyta

Cycadeoidophyta

Pteridospermophyta

Seeds ferns

All Extinct

Cycads

Extant

Cycadeoids

All Extinct

Appear in the upper Devonian Period

Fern with seeds apart of reproductive cycle

Seeds have been originated twice

Seed Fern Wood

Manoxylic

Softer and less dense

two types of shoots

Long Shoots

Short Shoots

Two types of Pines

Seed Cones

Pollen Cones

Ovuliferous Scale

Suspensor

Proembryo

Tiny Papery Leaves occur

Familiar long needle leaves

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Also known simple cones

single short unbranched axis

bears microsporophylls

Microspore mother cells

undergoes meiosis

Form microspores

Each develops endosporically

Also known as compound cones

More complex than pollen cones

Each consists of a shoot with axillary buds

Bears cone bracts not sporophytes

Each Bract has an axillary bud

bears the megasporophylls

Megasporophyll fused laterally to create <-

Still distinct and can be seen

In Larch, Fir, and Douglas

It is fused to the bract

first cells elongate

Zygote do not immediately form an embryo

Push the other cells deep

Into the megagametophyte

Develop into the embryo

No double fertilization

Female gametophyte continues to grow

Acts as a haploid nutritive tissue

Frequently confused with ferns/young palm trees

Size

Due to short trunks

Pinnately compound leaves

Typically short plants(1-2 M)

may grow up to 18M tall

Trunk

Covered in bark

Persistent leaf bases

remain on plant

Even after lamina

and Petiole have abscised

Internally

Stems similar to seeds ferns

Have a thick cortex

containing a secretory ducts

Surrounds a small amount of manoxylic wood

Tracheids

long and wide

rays are massive

Leaves

do not bear ovules

produce seed cones and pollen cones

Each on separate plants

Always dioecious

All are extinct

Vegetative features similar to cycads

differences between cycads

stomatal complexes

Leaf trace organization

Individual cones

contain both

Microsporophylls

Megasporophylls

Each Ovule has a stalk

megasporagnium is surrounds by integument

Extended out into long micropyle

Contains only a single living species

Ginkgo biloba

Also known as the maidenhair tree

Looks similar to a large dicot tree

with a stout trunk

several branches

Wood is similar to conifers

lacks vessels

lacks axial parenchyma

Has broad leaves

Dichotomously branched veins

similar to seed ferns

Contain both short and long shoots

short shoots bear almost all leaves

long shoots also bear few leaves

Reproduction

Dioecious

gymnospermous

Cones are not produced

Ovules occur in pairs

towards the end of the short stalk

Completely unprotected at maturity

autumn-gold-ginkgo-full-425x425

contains 3 groups of enigmatic plants

Ephedra

Welwitschia mirabilis

Gnetum

Approx. 30 species

Apppox. 40 species

this is the only species in genus

Mostly vines or small shrubs

Have broad leaves

similar to dicots

Native to 3 places

South East Asia

Tropical Africa

Amazon Basin

Tough shrubs and bushes

Common in desert regions

Southwestern US

Dry mountains in South America

Northern Mexico

Leaves are reduced

Scale like

Exist only in desert in South Africa

Short wide stems

only two leaves

Leaves grow perennially

from a basal meristem

Becoming increasingly longer

Spermatophytes

Manoxylic Wood

Gymnosperms

Pyncoxylic Wood

Angiosperms

s-l300

Gave rise to a monophyletic group

Clade that contains a woody plant

contains significant amounts of axial parenchyma

Such as the cycads

Wood with little or no axial parenchyma

Opposite of manoxylic wood

Such as gymnosperms and progymnosperms

Consists of strong

Hard woods

contain soft spongy wood

large compound leaves

Radically symmetrical seeds

Existed after the origin of wood

Before the seeds were trees

reproduced with spores similar to ferns

Produce seeds

Common name for naked seeds

Ovules located on flat sporophylls

All seed plants not angiosperms

Ex) Pine cones

Flowering plants

Those with carpels

Believed to be sporophylls

form tube like closed structures

fruits are mature carpels

cycads contain manoxylic woods

Cycadeoids and Cycads are closely related in several ways

Cycads are similar to ferns in classification