The Angiosperms
Part II
The Angiosperms
Some terminology…
Angiosperm phylogeny (part II)
Evolutionary trends (part II)
The Angiosperms
Some terminology…
Angiosperm phylogeny (part II)
Evolutionary trends (part II)
epiphyte
-grows entirely
in tree, with no
connection to
ground
hemiepiphyte
-starts in trees, sends
down roots
-this part is a root
Angiosperm
growth forms
liana
-woody
climber
vine
-herbaceous
climber
tree
shrub
-a single
trunk
many stems
liana
-starts on ground,
grows up tree
-this part is a stem
Compound vs. simple leaves
blade
blade
petiole
petiole
Simple leaf
Compound leaf
A few more floral terms
Hypanthium & bract
petals
sepals
hypanthium
bract
Placentation
placenta
Placenta
• tissue which bears
the ovules
Placentation
• arrangement of
placenta and ovules
inside the ovary
Ovary position
Floral symmetry
Radial
• many planes of
symmetry
superior
Bilateral
• only one plane of
symmetry
inferior
The Angiosperms
Some terminology…
Angiosperm phylogeny (part II)
Evolutionary trends (part II)
Monocots vs. “dicots”
•
•
•
•
•
•
•
flower parts in 3s
carpels fused, 3
1 cotyledon (first leaf)
parallel leaf veins
mostly herbs
scattered vascular bundles
lack true secondary growth
cotyledon
most other
angiosperms
ba
eu sal
dic
ots
Mo
no
co
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Ma
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oli
ids
AN
IT A
gra
de
“Dicots”
Rosids
Asterids
Remember:
Monocots are monophyletic,
“dicots” are not
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AN
IT A
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Eudicots
Rosids
Asterids
The Eudicots
• triaperturate pollen
• Petals and sepals in
multiples of 4 and 5
Mo
no
co
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Ma
gn
oli
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Am
bo
rel
la
Ny
mp
ha
ea
Illi
ce
ciu
ae
m
Eudicots
triaperturate pollen
uniaperturate pollen
gra
de
Ca
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dic
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AN
IT A
Eudicots
Rosids
Asterids
The Basal Eudicots
The Basal Eudicots
A mix of primitive and
derived features
Primitive:
• Carpels numerous & separate
• Stamens numerous, spiralled
Advanced
• filaments more or less defined
• petals reduced in number
•
•
Many exceptions to the above characters!
Primitive characters lost in the advanced dicots still persist within the
basal dicots
Example Basal Eudicots
Ranunculaceae (Buttercups)
Papaveraceae
(Poppy family)
Platanaceae
(Sycamore)
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AN
IT A
Eudicots
Rosids
Asterids
The Caryophyllales
Caryophyllales
•
Carpels fused
•
Unusual free-central placentation
•
Betalain pigments (unique to this
order)
•
Many (most?): no petals!
– Petal-like parts of flowers
derived from sepals, stamens,
or floral bracts
– Can be free or tubular
•
Many species use CAM and C4
photosynthesis
Caryophyllaceae
free-central placentation
“petals” derived from sterile stamens
Nyctaginaceae
petal-like structures derived from floral bracts and sepals
bract
sepals
Red Pigments
Betalains
all Caryophyllales
except
Caryophyllaceae
Anthocyanins
All other angiosperms
+ Caryophyllaceae
independent evolution?
Caryophyllales
Nyctaginaceae
Cactaceae
Caryophyllaceae
gra
de
Ca
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ba
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dic
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AN
IT A
Eudicots
Rosids
Asterids
The Rosids
Rosids
•
•
•
•
•
•
Huge, morphologically-diverse
clade
Carpels (separate but usually few)
to fully fused
Stamen few to many, but filament
generally well-defined
Petals free (mostly)
Compound leaves common
Hypanthium usually present
hypanthium
Hypanthium
Pyrus
(Rosaceae)
Myrtales
• Herbs, shrubs or trees
• Inferior ovary + hypanthium
• Hypanthium typically
functions in pollination as
nectar container or spur
Myrtaceae
Melastomataceae
Onagraceae
Floral tube is formed
from hypanthium,
not from corolla
Longitudinal section
of Fuchsia flower
(Onagraceae)
Fabales: Fabaceae
• Bean family
• “Legume” fruit
• Herbs to rainforest
canopy trees
• 18,000 species
• The dominant family (most
individuals and species) in
most tropical & subtropical
forests
• N-fixation common
Fabaceae
(pea family)
Compound leaves
Legume fruit
calyx
Subfamily Mimosoideae
•one of few examples of truly
tubular corolla outside the
Asterids (convergent!)
corolla
Fagales
• Trees and shrubs
• Wind pollinated
• Flowers tiny, in catkins
• N-fixers
• Commonly symbiotic
with root fungi: assist
uptake of soil nutrients
Alder (Alnus)
Oaks, walnuts,
alder, beech,
poplar
Oak (Quercus)
Fagales are dominant in many
forests of temperate zone and in
some tropical mountains
Oak forest,
Costa Rica
Brassicales
• Most are herbs
• Mustard oils: unique
to order
• Includes mustard,
broccolli, cauliflower,
cabbage, and
papaya
Brassicaceae
Caricaceae (papaya)
Brassicaceae
Mustard oils (Brassicales)
Characteristic odor
and taste of mustard,
horseradish, cabbage
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Ch
de
lor
an
tha
Ma
les
gn
oli
ids
Eudicots
Rosids
Asterids
The Asterids
Asterids
• Tubular corolla
• Stamens borne on
petals
• # stamens = or < #
petals (except
Ericales)
• Style usually single
• Carpels commonly
reduced to 2
• Iridoid compounds
Irididoid compounds
•
•
Restricted to the asterids
many different varieties,
especially in Asteraceae
Ericales
• “Basal” asterids
Theaceae
• Some have
separate petals
• Stamens frequently
> number of petals
Ericaceae (Blueberry family)
• note single style
• anthers open by pores
Fouqueriaceae (ocotillo)
Gentianales
• 14,000 species
• Mostly tropical
Apocynaceae
• Simple opposite
leaves with
stipules
Gentianaceae
Rubiaceae
Stipule
Rubiaceae
Solanales
• Radially symmetrical flowers with folds in corolla
• Mostly simple alternate leaves without stipules
• Rich in alkaloids
Convolvulaceae
Solanaceae: chile
Solanaceae:
tomato
Solanaceae
Alkaloids
• Toxic defensive compounds
• Many are psychoactive
(hallucinogenic)
• Common in Solanaceae, but
have evolved many times in
different eudicot lineages
Solanaceae
(asterid)
Cactaceae
(basal eudicot)
Lamiales
• Herbs to lianas to huge trees
• Bilaterally symmetrical flowers
• blah
Lamiaceae (Mint family)
Bignoniaceae
Bignoniaceae
Acanthaceae
Asteraceae (sunflowers)
•
•
•
Largest or second-largest
plant family (20-25,000
species)
worldwide distribution,
temperate zone and tropics
most are herbs, but also some
weak-wooded trees
Asteraceae (sunflowers)
•
•
flowers in “heads”
can contain 2 types
of flowers:
disc florets
ray florets
Asteraceae disk floret
Asteraceae are dominant in many open landscapes
(prairie, desert, tropical alpine)
The Angiosperms
Some terminology…
Angiosperm phylogeny (part II)
Evolutionary trends (part II)
Evolution of the carpel
leaf-like,
separate
enclosed,
with fusion of
multiple
carpels
Evolution of the stamen
leaf-like
clearly differentiated
into specialized
filament and anthers
Evolution of the
Angiosperm
flower
Floral reduction
and fusion
• Carpels: many, separate
to few, fused
• Perianth parts: all alike,
to clearly differentiated
sepals and petals
• Petals: many, free to
few, fused
• Ovary: superior to
inferior
Eudicots
ba
eu sal
dic
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Mo
no
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Ma
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oli
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AN
IT A
gra
de
Evolution of the angiosperm flower: carpel
Rosids
Asterids
ovary with
2 carpels
carpel fusion
and reduction
carpel fusion and reduction
carpels separate, usually numerous
Eudicots
ba
eu sal
dic
ots
Mo
no
co
ts
Ma
gn
oli
ids
AN
IT A
gra
de
Evolution of the angiosperm flower: stamens
Rosids
stamens with
distinct, threadlike filament
stamens with distinct,
thread-like filament
stamens laminar, undifferentiated
Asterids
Eudicots
ba
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dic
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Mo
no
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Ma
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oli
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AN
IT A
gra
de
Evolution of the angiosperm flower: perianth
Rosids
Asterids
fused corolla
distinct sepals and petals
flower parts in 4s & 5s
flower parts in whorls of 3
perianth undifferentiated, spiralled, numerous
Convergent evolution: succulent growth form
Euphorbia
• stem
succulent
Senecio
(Asteraceae)
• stem and leaf
succulents
Cactaceae
• stem
succulent
Aloe
•leaf succulent
Convergent evolution: petal-like structures
Nyctaginaceae
•petaloid floral
bracts
•petaloid sepals
Caryophyllaceae
•sterile stamens
(staminodia)
Zingiberaceae
•sterile stamens
(staminodia)
Convergent evolution: the fused tubular flower
Onagraceae
•tubular
extension of
apex of ovary
wall
(hypanthium)
Solanaceae
•fused petals
Nyctaginaceae
•fused sepals
•(plus sepal-like
bracts)
Amaryllidaceae
•fused sepals and
petals
Questions
1. What characters distinguish the basal eudicots, the
Caryophyllales, the Rosids, and the Asterids
2. What floral characters distinguish a “primitive” ANITA
angiosperm such as Illicium or the water lilies from an
“advanced” angiosperm such as an Asterid?
3. Provide examples of convergent evolution among the
Eudicots, and examples of taxa where they occur