Please enable JavaScript.
Coggle requires JavaScript to display documents.
Seed Plants: Seed Plants without Flowers (Division Ginkgophyta: Maidenhair…
Seed Plants: Seed Plants without Flowers
Division Progymnosperms: Progynosperm
Archseopteridales
trees up to 8.4 m tall with wood and secondary phloem
stems has a pith surrounded by a ring of primary xylem bundles
reproduction was heterosporous; mega and micro spores
Evolution of Seeds
it produced one very large megaspore and three small aborted cells
the earliest known Progymnosperm with heterospory is Chauleria (390million years ago)
integument surrounded the megasporngium
there was also a large micropyle which permitted the cells to swim to the egg
space above the megasporangium because the place when the spores settled called the pollen chamber
change occurred in their wall, in their germination, and in the nature of the microgametophyte
Aneurophytales
they vary from large trees to small shrubs
vascular cambium and secondary growth
primary xylem was a protostele
they had webbing between branches but not leaves yet
Division Progymnosperms: Seed Ferns
had a long-lived vascular cambium that produced both xylem and phloem
the wood was softer
first appeared in the upper Devonian period
they were any woody plants with fern-like foliage that bore seeds instead of sor
unlike the Progymnosperms their tracheids were longer and wide; several rows of pits occurred at the radial wall
they form a grade and not a clade
leaves were similar to true ferns; they had large megasporangium
Division Cycadeoidophyta: Cycads
short plants 1 or 2 meter; 100 species; they occur in warm places in the US
internally they are similar to seed ferns
their leaves do not bear ovules; instead they produce seed and pollen cones
they are always dioecious;
the seed cones are large with compound megasporallys
Division Cycadeoidophyta: Cycadeoids
they are all extinct
they were very similar to cycads
they differ in the stomatal complexes and in leaf trace organizations
the microsporophyll was a cup shaped and contained multiple micosporagia
Division Coniferophyta: Conifers
they are diverse with 550 species; they are all trees that vary from moderate to gigantic in size
their leaves are always needles
leaf veins have endodermis and a tissue called transfusion tissue
all conifers have pollen cones( simple cones) and seed cones(compound cones)
pines have two types of shoots; short(produces long needle leaves) and long shoots( tiny papery leaves)
conifer pollen occurs before the egg is mature
Division Ginkgophyta: Maidenhair Tree
this contains a single living species
it is very unusual; it looks like a dicot tree
it lacks vessels and axial parenchyma
they have both short and long shoot
reproduction is dioecious but no cones are produced
ovules occur at the ends of short stalk and they are exposed
their ancestors are not known
Division Ginkgophyta
it contains three groups of enigmatic plants
Ephedra
Welwitschia mirabilis
Gnetum
mostly vines or small shrubs with broad leaves
native to southeast asia, tropical Africa, and the amazon basin
scale-like leaves
the pollen is distinctive
the fossils are only a couple million years old
further research will be done on this group to decide if they do belong to the anthophytes or not
Progymnosperms are extinct
evolution of vascular cambium with unlimited growth potential
the wood was strong; true woody trees
