Please enable JavaScript.
Coggle requires JavaScript to display documents.
Vascular Plants Without Seeds (Early Vascular Plants (Rhyniophytes (Types…
Vascular Plants Without Seeds
Theories of Plant Development
Interpolation hypothesis
Monobiontic into dibiontic
Zygote germinated mitotically
Sporophyte generation introduced
Evolved in complexity
Gametophyte generation small
Algae
Nonvascular plants
Vascular plants
Vascular cryptogams
Seed plants
Transformation theory
Diverged into two clades
Nonvascular plants
Sporophytes became simpler
Vascular plants
Sporophytes became complex
Gametophytes reduced
Dibiontic life cycle arose
Gametophyte and sporophyte
Vascularized
Became larger
Became more complex
Early Vascular Plants
Rhyniophytes
Characteristics
Only central cells sporogenous
Terminal sporangia
Homosporous
No separate microspores & megaspores
Equal dichotomous branching
Two branches
Equal size and vigor
Upright stems
No leaves
Endarch protostele
Sporangia location
Masses at branch ends
Types of rhyniophytes
Rhynia
Aglaphyton
Cooksonia
Lyonophyton
Gametophytes only
Sciadophyton
Gametophytes only
Hornephyton
Xylem Structure
Protostele
Center of solid xylem
Two types
Endarch protostele
Derived trait from Rhyniophytes
Protoxylem in center
Differentiates when cells small
Metaxylem on edge
Differentiates when cells expanded
Found in rhyniophytes
Exarch protostele
Derived trait from Zosterophyllophytes
Protoxylem on edge
Metaxylem in center
Found in zosterophyllophytes
Siphonostele
Pith in center
Found in ferns/seed plants
Zosterophyllophytes
Characteristics
Sporangia
Opened transversely
Positioned laterally
Exarch protostele
Homosporous
Stems
Lower stem
None of those structures
Upper stem
Ordinary epidermal cells
Stomata
Cuticle
Small herbs
No secondary growth
Most dichotomously branched
Types of zosterophyllophytes
Zosterophyllum
Principal genus
Asteroxylon
Had enations
Outgrowths of photosynthetic tissue
Rebuchia
Sporangia on specialized branches
Crenaticaulis
Some pseudomonopodial branching
Microphyll Line of Evolution
Lycophytes
From
Zosterophyllum
-like ancestor
Heterospory
Cones or strobili
Clusters of sporangia
Development of heterospory
Megaspores
Megagametophytes
Microspores
Microgametophytes
Extant Genera
Selaginella
S. lepidophylla
Resurrection plant
Curls up, turns brown
Reopens green when moistened
Characteristics
Heterosporous
Megagametophyte
Develop in spore wall
Microgametophyte
Develop in spore wall
Ligules
Small tissue flap
On upper leaf surfaces
Isoetes
Quillworts
Grow in wet, muddy areas
Characteristics
Small corm-like stem
Roots attached below
Leaves attached above
Ligules
Weak cambial growth
Additional exterior cortex parenchyma
Additional interior vascular tissue
CAM photosynthesis
Heterosporous
Lycopodium
Small herbs
True roots
Short upright branches
Prostrate rhizomes
Homosporous
Sporangia
In cones
Distributed among shoots
Gametophytes
Some green and photosynthetic
Others subterranean and heterotrophic
"Ground pine", "Club moss"
Morphology
Earliest lycophytes
Drepanophycus
and
Baragwanathia
Enations were large
Microphylls
Single trace of vascular tissue
True roots
Sporophytes could grow large
Some secondary growth
Extinct types of lycophytes
Vascular cambium
No radial longitudinal division
Wood thickness < 10cm
Current-looking secondary xylem
Megaphyll Line of Evolution
Euphyllophytes
Monilophytes
Ferns
Pteridophyta
Environments
Most places
Lakesides
Dry, hot deserts
Moist, shady forests
Surface of water
Submerged below water
Characteristics
Perennial and herbaceous
Endarch siphonostele
Leaf traces diverge
Leaf gaps created
Homosporous
Except the two water ferns
Leaves
Almost always compound
Rachis and leaflets
Leaf primordia
Fiddlehead
Sori
Clusters of sporangia
Underside of leaf
Reproduction
Gametophytes
Small and simple
Heart- or ribbon-shaped
Photosynthetic
Both antheridia and archegonia
Sporophytes
Homosporous
Become independent
Sporangia development
Leptosporangia
Single surface cell
Divides periclinally
1 more item...
Few spores produced
Only in clade Leptosporangiatae
Eusporangium
Surface cells
Undergo periclinal divisions
2 more items...
Large with many spores
Fundamental type
Special genera
Psilotum
Simplest vascular plants
No roots or leaves
Similar to
Rhynia
and
Aglaophyton
Gametophytes
Heterotrophic
Contain vascular tissue
Tmesipteris
Simplest vascular plants
Leptosporangiate ferns
Most familiar
Most species
Equisetophytes
Arthrophyta
Characteristics
Aerial stems
Whorled pattern of leaves
Megaphylls
Single trace of vascular tissue
Herbaceous
No secondary growth
Siphonosteles
Endarch
Sporangiophore
Group of 5-10 sporangia
Arranged in a strobilus
Both sporangia clustered in strobili
Monopodial growth
Gametophytes
Either male or bisexual
Grow in moist habitats
Horsetails
The 15 extant species
Scouring rushes
Origin of megaphylls
Three types of "leaves"
Enations/microphylls
Zosterophyllophytes and lycophytes
Megaphylls
Seed plants, ferns, equisetophytes
Leaves on gametophytes
Nonvascular plants
Telome theory
Explains megaphyll evolution
Overtopping of main branches
Planation of telomes
Parenchyma develops between telomes
Sporophyll
Leaf-like structure
Bears sporangium
Trimerophytes
Transition between Rhyniophytes and Euphyllophytes
Three extinct genera
Psilophyton
Pertica
Trimerophyton
Strongly resembled Rhyniophytes
Terminal sporangia
Dehisced laterally
Dichotomous branching
Homosporous
Endarch vascular cylinder
Tracheids
Special features
Pseudomonopodial branching
Single main trunk
Overtopping
Unequal branching
One stem more vigorous
Phyllotaxy
Alternate
Decussate
Regular spiral
Distichous
Tetrastichous
Whorled
