Please enable JavaScript.
Coggle requires JavaScript to display documents.
Seed Plants I: Seed Plants Without Flowers ("Gymnosperms")…
Seed Plants I: Seed Plants Without Flowers ("Gymnosperms")
Gymnosperms
The gymnosperms are those plants with "naked ovules," that is,ovules located on flat sporophylls.
Examples: Pine cones
Angiosperms
#
Angiosperms are the flowering plants, those with carpels, which are believed to be sporophylls that form a tube-like, closed structure; fruits are mature carpels.
Division Progymnospernatophyta : Progymnosperms
Aneurophytales
It contain the more relictual progymnosperms.
Aneurophyton
Protopteridium
Proteokalon
Triloboxylon
They varied in stature from shrubs to large trees, up to 12m tall.
They all had a vascular cambium and secondary growth.
Archaeopteridales
A more derived progymnosperm was Archaeopteris in the order Archaeopteridales
Stem of Archaeopteris had a siphonostele, pith surrounded by a ring of primary xylem bundles, much like modern conifers and dicots.
Heterosporous was the reproduction of archaeopterids.
Evolution of Seeds
in free-sporing species, spores can be identified with sporophytes
spores cannot be identified with gametophytes except when gametophytes
spores in a sporangium attached to leaves or wood during fossilization
as they fused to each other and to the megasporangium, the space at the top became the place of microspores.
Division Pteridospermophyta : Seed Ferns
:<3:
Progymnosperms gave rise to another line of gymnosperms plants to the conifers.
#
these are classified as three divisions:
Pteridospermophtya
cycadeoidophyta
Cycadophyta
not all are closely related to each other
they had a ring of vascular bundles surrounding a pith,
many resembled modern tree ferns, others were vines
Pteridosperms are thought to have evolved from the Aneurophytales
the earliest
seed fern
appeared in the Upper Devonian Period
Division Coniferophyta: Conifer
Conifers leaves are always simple needles or scales.
They are familiar plants.
Conifers are never vines, herbs, or annuals, and also they never have bulbs or rhizomes.
Leaf veins which have an endodermis and a tissue called transfusion tissue.
It consisting of transfusion parenchyma cells and transfusion tracheids.
There leafs are always simple needles or scales.
Tiny papery leaves occur on long shoots and in their axils are short shoots.
Division Cycadophyta: Cycads :star:
text
They have stout trunks with pinnately compound leaves.
The trunk is covered with bark and persistent leaf bases.
Most of the cycads are short plant which is less than 1 or 2 m tall.
Cycad ovules are like those of seeds ferns, having a large, vascularized megasporangium and a loosely attached, vascularized integument.
Modern cycads are highly prized ornamentals in the warmest part.
Division Cycadeoidophyta: Cycadeoids :explode:
They had vegetative features almost identical to those of cycads.
Two Group differ
Differentiation of stomatal complexes
In leaf trace organization
Cycadeoids would never be considered distinct from cycads.
Cone of Cycadeoids contained both microsporophylls and megasporophylls
Division Ginkgophyta: Maidenhair Tree :<3:
It contain a single living species.
Ginkgo biloba
It has broad leaves.
It looks much like dicot tree with a stout trunk and many branches.
The ovules of Ginkgo are large and develop a three-layered seed coat.
Division Gnetophyta
This division contains three groups of enigmatic plants.
Ephedra
Welwitschia
They have short and wide stem and only two leaves.
Gnetum
They are mostly vines or small shrubs with broad leaves.
They are mostly vines or small shrubs with broad leaves.
Concepts
Gymnosperms
#
Angiosperms .
Spermatophytes
