Download Introduction to Flowering Plants:

Introduction to Flowering
Plants:
Angiosperms: (Magnoliophyta) p. 403-404
Passiflora incarnata,
eastTexas
Calliandra eriophylla,
Baja California
Diversity of Flowering plants
(p. 403)
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Largest plant group
Roughly 250,000 species.
 Some estimates > 400,000!
13,185 genera (Thorne 2001).
462 families (APG).
Dominate most land habitats
worldwide.
Guara_longiflora, E. Texas.
Opuntia, E. Tx.
Bignonia capreolata, E. Texas
Hydrolea ovata, E. Texas
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Characteristics of Flowering
Plants
Seed plants
Carpels enclose ovules and...
Fruit encloses seeds.
Advanced (water conducting) & phloem
(food conducting) tissue anatomy.
Sporophylls (sporangium-bearing
appendages) arranged as a Flower.
Anisacanthus
Big Bend Nat. Park
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Universal Angiosperm
Flower Characters
Relative position of parts on floral axis constant.
Carpels always uppermost.
Stamen structure: (4 sporangia in 2 pairs).
2 basic Pollen types:
1 groove or opening (monocolpate, etc.)
 Magnoliids & monocots.
3 or more openings (Tricolpate)
 Eudicots.
Morphological, fossil & molecular evidence:
Angiosperms are a monophyletic group (p. 403).
Origin of Flowering Plants
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Darwin: “Abominable mystery”.
 Sparse fossil record, etc.
 Recent research: many long standing
phylogenetic questions answered.
Origin:
 Possibly early Cretaceous
(130 M.Y.B P.)
 Oldest Fossils: Cretaceous (124
M.Y.B.P).
Already much morphological diversity
in early fossils:
 Insect & wind pollination.
 Perfect & imperfect flowers.
 Flowers with both many & few parts.
What Were the Earliest
Flowering Plants Like?
Based on supposed ancestral features
of “basal” lineages (Amorelaceae,
Austrobaileyales, Magnoliids):
 Woody perennials.
 Primary vascular bundles in ring.
 Simple, entire, evergreen, leathery,
estipulate leaves.
 Perfect, symetric, insect-pollinated
flowers.
 Flowers hypogenous, several-many
distinct parts.
 Apocarpous; weak differentiation of
stigma/style/ovary.
 Stamens: weak differentiation of
anther & filament.
 Pollen with 1 aperture.
Magnolia
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Early Fossils
Archaefructus sinense; 24.6 Million years old.
Simple flowers, many stamens & carpels, elongate
receptacle; No perianth.
Semi aquatic.
Early Fossils
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Australian fossil
120 Million
years old.
Small imperfect
flowers, few
parts.
Probably wind
pollinated.
Early Fossils
Archaeanthus linnenbergeri
100 Million years old.
Magnolia-like.
Perfect flowers with many parts.
Probably insect pollinated.
Classification of Angiosperms
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1)
We follow the APG system (p.1163).
3 small basal lineages (names below).
 “ANITA grade”
 ANITA= selected genera: Amborella,
Nymphaea, Illicium, Trimenia and
Austrobaileya.
3 main groups
 Magnoliids
 Monocots
 Eudicots
Phylogenetic tree P. 1165.
Amborella;
Amborellales
2)
Nymphaea;
Nymphaeales
3)
6)
Alternanthera; Eudicot
5)
Arisaema; Monocot
4)
Illicium;
Austrobaileyales Magnolia; Magnoliid
Phylogeny of
Angiosperms:
3 ANITA Clades:
Amborellaceae
Nymphaeaceae
Austrobaileyales
Magnoliids
Monocots
Eudicots
(Tricolpates)
Characters of Angiosperm Groups
Cotyledon
Vascular Pollen Leaf
Bundles Openings Venation Number
Flower
Parts
Basal Clades
(ANITA)
Variable
1
2
Variable
1
Magnoliids
2
3x
1
Monocots
1
3x
Eudicots
(Tricolpates)
3
4-5x
2
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Floral Formulas to Describe
Flowers
Describes the Calyx (Ca), Corolla (Co), Androecium (A), &
Gynoecium (G)
Numbers refer to number of parts: (CA3 = 3 sepals).
X= indefinite or variable number of parts.
∞ = many parts (15-20 or more).
Circles around numbers indicate connate parts (G2).
“Z” (CaZ CoZ): Calyx or corolla is zygomorphic (asymetric).
Superior ovaries: underline “G”.
Inferior ovaries: line over “G”.
Ca3 Co3 A6 G3
Floral Formulas (Continued)
Adnate parts: Arching line connects symbols for adnate
parts:
 Under if fused at base (most carpels, petals, etc).
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Above if fused from top.
 Example: Ca5 Co5 A5 G2
Additional information (fruit type, etc.) may be written
below.
Ca5 Co5 A5 G2
Floral Formulas (Examples)
Ca3 Co3 A6 G3
Ca5 CoZ3+ 2 A9 +1 G1
The End
Sesuvium portulacastrum, (Aizoaceae) Galveston, Texas
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