BIOL 448.34

Systematic Botany. Lecture 34

Alexey Shipunov

Minot State University

November 23, 2011

BIOL 448.34

Outline

Questions and answersClassification of angiosperms

Basal angiospermsMagnoliidae—“ANTITA” clade

BIOL 448.34

Outline

Questions and answersClassification of angiosperms

Basal angiospermsMagnoliidae—“ANTITA” clade

BIOL 448.34

Questions and answers

Previous final question: the answer

Why angiosperms conquered the land?

I They filled ecological niche of seed herbs because ofoptimized life cycle

I Then they expanded to the tree level again because theyblocked succession pathways («cenophobe» theory)

BIOL 448.34

Questions and answers

Previous final question: the answer

Why angiosperms conquered the land?

I They filled ecological niche of seed herbs because ofoptimized life cycle

I Then they expanded to the tree level again because theyblocked succession pathways («cenophobe» theory)

BIOL 448.34

Questions and answers

Classification of angiosperms

Questions and answersClassification of angiosperms

BIOL 448.34

Questions and answers

Classification of angiosperms

Milestones of angiosperm classificationI Carolus Linnaeus (XVIII century) gathered all available

information, established species and generaI Michel Adanson and Antoine Jussieau (end of XVIII)

established plant familiesI John Lindley (middle of XIX) invented plant ordersI Alfred Engler and Charles Bessey (XIX-XX) started

evolutionary classificationsI Arthur Cronquist, Rolf Dahlgren, Armen Takhtajan and

Robert Thorne (XX-XXI) developed different well-arguedcontemporary classifications based on morphology

I From 1993, Angiosperm Phylogeny Group (APG) as wellas several individuals started to employ molecularcharacters. Luckily, one of the most accessible chloroplastDNA genes, rbcL, appeared to be extremely useful fortracing changes on family and order levels

BIOL 448.34

Questions and answers

Classification of angiosperms

Taxonomic map of angiosperms: subclasses

BIOL 448.34

Questions and answers

Classification of angiosperms

Taxonomic map: orders

BIOL 448.34

Questions and answers

Classification of angiosperms

Dendrogram of subclasses

BIOL 448.34

Questions and answers

Classification of angiosperms

Cladogram of subclasses

BIOL 448.34

Questions and answers

Classification of angiosperms

Paraphyly

BIOL 448.34

Questions and answers

Classification of angiosperms

Magnoliidae portrait

Nymphaea sp. (water-lily)

BIOL 448.34

Questions and answers

Classification of angiosperms

Liliidae portrait

Acorus calamus (calamus, or sweet flag)

BIOL 448.34

Questions and answers

Classification of angiosperms

Rosidae portrait

Geranium sp. (wild geranium)

BIOL 448.34

Questions and answers

Classification of angiosperms

Asteridae portrait

Penstemon sp. (beard-tongue)

BIOL 448.34

Questions and answers

Classification of angiosperms

Evolutionary history of subclasses

I Magnoliidae are historically most ancient, first fossilsappear in Late Jurassic. They dominate fresh waters andmaybe, filled lower floors of forests in Cretaceous

I Liliidae appeared in Lower Cretaceous, they started todominate grasslands in Neogene

I Rosidae appeared in Lower Cretaceous, they madebroad-leaf forests in Late Cretaceous and onwards

I Asteridae originated in Middle Cretaceous, they started arapid divergence in Paleogene

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Basal angiospermsMagnoliidae—“ANTITA” clade

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Archaefructus

I Fossil water plant from lower Cretaceous of ChinaI Very primitive fructifications which are not yet compacted

in flowerI Multiple free carpels, paired stamens

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Archaefructus reconstruction

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Amborella

I Small forest shrub of New Caledonia (big island in Pacificocean)

I Have irregular flowers, stylar canal, unusual embryo sac(with three synergids and no antipods)

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Amborella, branch with male flowers

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Amborella, diagram and formula

∂P9−11A12−21; ∂P7−8St2G4−6(where “St”are staminodes, non-functional stamens)

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Amborella stylar canal

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Trithuria

I Wetland and water plants from south Asia and AustraliaI Have unusual structure of fructifications (“non-flowers”)

where male organs typically positioned in the center of?inflorescence/flower

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Trithuria general view

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Trithuria fructification

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Summary

I From four subclasses of angiosperms, two (Magnoliidaeand Rosidae) are paraphyletic

I Fossil Archaefructus, Amborella and Trithuria are mostprimitive angiosperms

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Final question (3 points)

Which of four subclasses is basal? Why?

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

Final question (3 points)

Which of four subclasses is basal? Why?

BIOL 448.34

Basal angiosperms

Magnoliidae—“ANTITA” clade

For Further Reading

Margulis and Chapman. 2009.Kingdoms and domains: an illustrated guide to the phyla oflife on Earth. 4th edition.