Module 2: Gross Morphology of Vascular Plants Flashcards
what are vascular plants?
they have vascular tissues (xylem and phloem)
what makes up a xylem’s wall?
lignin
what are the functions of each vascular tissue?
xylem is for water conduction while phloem is for photosynthate function also for food conduction
T or F: phloem is lignified
F
T or F: phloem flow is bidirectional
T
what are the extant vascular plant groups discussed?
Lycophytes
Spheophytes
Psilophytes
Ferns
Gymnosperms
Angiosperms
where did the earliest vascular plants descended from?
earliest green algae
two groups that descended from green algae that are now extinct
Rhyniophytes
Zosterophyllophytes
characteristics of Rhyniophytes
- dichotomous branch terminated in spore capsules called sporangia
- no leaves
- Homosporous
- endarch xylem
oldest Rhyniophyte representative
Cooksonia
three distinct characteristics of Zosterophyllophytes
- lateral sporangia
- sporangia opens traversely along the top edge
- exarch xylem
describe the xylem positioning of Zosterophyllophytes
exarch: protoxylem on the outer margin, metaxylem in the center
T or F: Zosterophyllophytes have secondary growth
F, they are small herbs w/o secondary growth
vascular plants that arose from Rhyniophytes
seed plants and ferns
vascular plants that arose from Zosterophyllophytes
Lycophytes
mosses
liverworts
hornworts
—phylls meaning?
leaves
—phores meaning?
stalks
sporo— meaning?
spores or sporangia-containing
a container for production and storing spores
sporangium
types of spore production
- homosporous having one type of spore
- heterosporous having mega and microspores
types of sporangium
megasporangium and microsporangium
what do you call the seedless vascular plants?
Pteridophytes
differentiate fern from fern allies
- fern has leafy fronds and megasporophyll w sori
- fern allies have small, scale-like microsporophyll
how do Pteridophytes reproduce?
via spores found in sporangia
two major Phyla under Pteridophytes group
- Lycophyta
- Pterophyta/ Filicophyta
vascular plants under Phylum Pterophyta
- Sphenophytes
- Psilophytes
- true ferns
describe plants in the Silurian Period
- no leaf or roots
- green photosynthetic stem w sporangia at tip
describe plants in the Devonian Period
- beginning of freshwater algae
- roots/ root-like structures arose
- enations present
describe plants in the Carboniferous Period
- dominated tropical/ subtropical
- forest-forming trees
- thin woody stems
- w vascular cambium
characteristics of Lycophytes
- resemble Zosterophyllophytes
- w microphylls (single vascular tissue)
Genera under Lycophytes
- Lycopodium
- Selaginella
- Isoetes
describe Lycopodium
- sporophylls arranged in strobili
- homosporous
- on the ground/ epiphytic
- have rhizomes w adventitious roots
- stems w spirally arranged microphylls (single vein)
- gametophyte is underground
mode of reproduction of Lycopodium
asexual via:
- rhizomes or runners
- gemmae (at the tip of the stem)
most diverse Lycophyte
Selaginella
describe Selaginella
- small herbs w no secondary growth
- unbranched or dichotomously branched
- w rhizophores on stem that produce adventitious roots at free ends
- spirally arranged microphylls
- sporophylls form strobili
- w ligules at adaxial side
- heterosporous
function of ligules
to exude water or keep moisture in young leaves and sporangia
how does Selaginella propagate?
via tubers, bulbils, dormant buds, and fragmentation
what causes the color of Sellaginella?
iridoblast
it is a desert plant that can withstand almost complete dessication
resurrection plant or Selaginella lepidophylla
what are plants that have body structure and functions that depend on the availability of water?
Poikilohydric plants
describe Isoetes
- aquatic/ semi-aquatic
- stout, coiled roots at the leaf base; slender, straight near the stem end
- hollow and quill-like w minute ligule
- leaf contains single vein w 4 chambers
- heterosporous
- spores are covered w velum
difference and similarity of the life cycles of Selaginella and Isoetes
- Isoetes’ ligule contains the mega and microsporangium
- they are both heterosporous
what are the most primitive vascular plants?
Psilophytes
describe Psilotum
- highly simplified ferns
- upright, dichotomous branching
- no roots and leaves; w enations
- rhizoids on rhizome (associated w mycorrhizal fungi)
- monoecious
- homosporous
T or F: rhizome is multicellular and diploid
F, it is unicellular and diploid
what is mycorrhizae?
symbiotic association between fungi and plants
explain the relationship between mycorrhizae and Psilotum
mycorrhizae increases the surface area of plants for absorption while Psilotum gives carbs to mycorrhizae
leaf-like structures that are similar to microphylls and is present in Psilotum
prophyll
this is the fused sporangia in Psilotum
synangium
explain the evolution of stems giving rise to megaphylls
- overtopping
- planation
- webbing
T or F: all megaphyllous plants believed to be f monophyletic clade
T
difference of megaphylls from microphyll
- more than 1 vein
- w leaf gap
leaf gaps are also called
lacuna
it is the vascular tissue in the stem that is diverted towards the leaf and causes the formation of leaf gaps
leaf traces
leaf gaps are filled w what type of cells?
parenchyma cells
two types of aerial shoots of Equisetum
fertile stem and sterile stem
Equisetum can cause itching because?
of its high silica content
describe Equisetum
- have small megaphylls
- w rhizomes that are vertical
- w true roots at the nodes of rhizomes
- homosporous
differentiate the shoots/ stems present in Equisetum
- sterile: branched, photosynthetic, w nodes and internodes
- fertile: unbranched, w terminal strobilus, w leaf sheaths, hollow stem
in Equisetum, this is the sporangia-bearing stalk
sporangiophore
what is the mode of reproduction of Equisetum?
- spores
- vegetative via tuber in the rhizomes or via branch primordia developing into new branches after decay of old rhizomes
special structure found in the spores of Equisetum
elaters for swimming
T or F: ferns produce secondary xylem
F
characteristics of the fern sporophyte
- single axis
- true roots
- megaphyllous leaves
- no secondary growth
fern that exhibit secondary growth
Botrychium
this is the expanded leafy part of the frond
blade
this is the whole fern leaf
frond
it is the stalk within the blade
axis/ rachis
a primary division of the fern blade
pinna
a division of the pinna
pinnule
what do you call the uncurling frond?
fiddlehead
the stalk below the blade
stalk/ stipe
examples of ferns with simple leaves
Platycerium and Asplenium
characteristics of frond
- may be leathery or delicate
- almost always compound
- some have simple leaves
it is the midrib of the pinna
costa
frond division wherein the blades are deeply lobed but not fully divided
pinnatifid
what are the two kinds of fronds
fertile and sterile
characteristics of scale or nest frond
- sessile
- brown sterile
- captures debris as humus for the plant
- protect the rhizome from exposure to sunlight and wind
functions of scale or nest frond
- laminate the plant against the tree
- protect the plant from damage
characteristics of Platycerium
- has two distinct type of fronds
- has spores on the underside of the frond
- looks like a lily pad
it is the fertile part of Platycerium that produces spores
green bifurcated fronds
sterile part of Platycerium
flat basal shield leaf
the sterile part of Platyceria has a similar function to the scale frond of what plant?
Drynaria
how is the fiddlehead produced in ferns?
cell division in the leaf primordium
it is the uncoiling of the fiddlehead
circinate vernation
where are sori found?
on the abaxial side of the leaf; edge of pinna or away from the pinna margin
it is a cluster of sporangia
sori
it is a flap of tissue that protects the sori in ferns
sori indusium
types of indusium
true and false
where is the sporangia found in ferns?
underside of the frond
most ferns produce how many spores in each sporangium?
64 spores
what is a true indusium?
delicate membranous structure on the abaxial side of the pinna and is an epidermal growth
what is false indusium?
structure formed by the curving of pinnae margins on the adaxial side
what is the function of each type of indusium?
- true indusium: covers the sorus and protects the sporangia
- false indusium: protects the marginal sori
it is a distinct characteristic of ferns
they have a prothallus
what is the fern prothallus?
gametophyte of the fern
T or F: new fern sporophyte is dependent on the tiny gametophyte
T
where did cambium arise?
Lignophytes: progymnosperms
these are the first seed plants
Spermatophytes
characteristics of spermatophytes
- megasporophylls are arranged in upright cone-like structures
- microspores germinate into a male gametophyte that produces antheridia and sperm cells and carry out fertilization
two subdivisions of spermatophytes
- Gymnosperms
- Angiosperms
Phylum under Gymnosperms
- Coniferophyta
- Cycadophyta
- Gnetophyta
- Ginkgophyta
describe Gymnosperms
- naked ovules
– borne unprotected on the surface of the megasporophylls - seed-bearing plants without ovary
characteristics of conifers
- have strong monopodial vegetative growth
- exhibits strong apical dominance
- stems and roots with active vascular cambium
- with well-developed taproot system
- have thin megaphyllous leaves called needles
- monoecioius or dioecious
what is apical dominance?
inhibitory control exercised by the apical portions of the shoot over the growth of the lateral buds below
function of conifer needles
less surface area for less water evaporation
any plant that is adapted to dry habitat
xerophytes
examples of xerophytic adaptations
- thick fleshy leaves or stems
- waxy coatings
- ability to drop leaves during dry periods
- ability to fold leaves to reduce sunlight absorption
- hair covering
how many years do pine needles last?
2 years
T or F: Pinus are mostly dioecious
F, they are monoecious
what is seed-scale complex in pines?
pine female cones’ seed scale with its seed bract
pine female cones are subtended by what structure?
sterile bract
T or F: in pines, sperms are flagellated
F, non-flagellates and are carried directly to the egg by a pollen tube
T or F: pine nuts are not fruits
T
characteristics of Cycas
- palm-like evergreen plant
- stem is thick, woody, and unbranched
- aerial part remains covered by a thick armor of large and small leaf bases
- count number of crowns for age
the aerial trunk of Cycas is called
caudex
the pinnately compound leaves on top of Cycas is called
crown
two types of Cycas roots
- normal taproots
- coralloid roots
describe Cycas normal taproot
- positively geotropic
- no root hairs
- for anchorage and absorption
describe Cycas coralloid roots
- developed as lateral branches
- get infected with bacteria, fungi, and algae and producing swollen tips
two types of leaves in Cycas
- compound foliage leaves
- scaly leaves
what are compound foliage leaves?
- green, large pinnately-compound megaphyllous leaves
- spiny petiole and a strong, large rachis
- composes the crown
what are scaly leaves?
- small and brown
- protect reproductive structure and shoot apex
- alternates with foliage leaves
how long does Cycas produce cones?
after more than 10 years
describe Cycadophyta cones
- strictly dioecious
- male cone is terminal while megasporophylls are produced in succession with the leaves at the top of the stem
where is the Cycadophyta male cone produced?
at the shoot apex
describe female cones of Cycas
composed of large megasporophylls that produce ovules
describe Cycadophyta megasporophyll
- modified foliage leaf
- upper pinnate leafy portion, middle ovule-bearing portion, proximal petiole
Phylum which is the missing link between gymnosperm and angiosperm
Phylum Gnetophyta
describe Gnetophyta
- members are woody shrubs, trees, or vines
- exhibit angiosperm-like characteristics
- believed to be the predecessors of flowering plants
- maybe monoecious or dioecious
- does not form fruit
- have vessels in their xylem
why is Gnetum called angiosperm-like?
they have angiosperm-like leaves with broad, entire-margined lamina with pinnate-reticulate venation and multiple vein orders
three genera under gnetophyta
- Ephedra
- Gnetum
- Welwitschia
describe Gnetophyta cones
organized into inflorescence-like structure similar to panicles
T or F: Gnetum vessels are homologous to Angiosperm vessels
F
describe Ginkgophyta
- short and long shoots
- short shoots bearing the leaves
- looks like a dicot tree with stout trunk and many branches
- lacks wood vessels
- dichotomously-branched veins, broad leaves
- dioecious without cones
- pollen resembles a catkin, have stalk, several sporangiophores each have 2 microsporangia
