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PBIO 250 Lecture Notes

James L. Reveal

Norton-Brown Herbarium, University of Maryland


Sources of Taxonomic Evidence

Kinds of Sources for Taxonomic Evidence
   (1) morphology, anatomy (follow the links), embryology
   (2) cytology, palynology, paleobotany, ecology
   (3) pollination biology
   (4) chemosystematics, genetic sequencing data

Morphology
review of plant morphology
floral and vegetative morphology
reproductive structures
John Lindley (1799-1865)
The vegetable kingdom (1846)
George H.M. Lawrence (1919-1978)
Taxonomy of vascular plants (1951)
Albert E. Radford et al.
Vascular plant systematics (1974) - see Classified glossary from Vascular Plant Taxonomy

  • gross morphological features
    Arthur J. Eames (1881-1969)
    1. Bell, A.D. 1991. Plant form. An illustrated guide to flowering plant morphology. Oxford.
    2. Eames, A.J. 1961. Morphology of the angiosperms. New York.
    3. Sporne, K.R. 1975. The morphology of angiosperms: The structure and evolution of flowering plants. New York.
  • comparative plant anatomy
    review of plant anatomy in two parts
    Charles R. Metcalfe (1904-1991)
    Laurence Chalk (1895-1979)
    Anatomy of the dicotyledons (1979-1983)
    Anatomy of the monocotyledons (1960-1982)
    1. Esau, K. 1965. Plant anatomy, ed. 2. New York.
    2. Mauseth, J.D. 1988. Plant anatomy. Menlo Park.
    3. Rudall, P. 1992. Anatomy of flowering plants. An introduction to structure and development, ed. 2. Cambridge.
    4. Weberling, F. 1989. Morphology of flowers and inflorescences, trans. by R.K. Pankhurst. Cambridge.

    evolutionary trends in secondary xylem
    Irwin W. Bailey (1884-1967)
    tracheids (right) to vessels
    sieve-element plastids
    Richard Eyde (1928-1990)
    vestigial or modified parts
    vascularization
    stomatal types
    Sherwin Carlquist (1930- )
    conservative characters
    adaptation and function
    evolutionary adaptation to environmental stress
    island biogeography and specialization

    1. Carlquist, S. 1974. Island biology. New York.
    2. --. 1975. Ecological strategies of xylem evolution. Berkeley
    3. --. 1988. Comparative wood anatomy. Berlin.
  • embryology
    microsporogensis and megasporogensis gametophytes
    fertilization
    endosperm
    embryo
    seed coats
    1. Maheshwari, P. 1950. An introduction to the embryology of angiosperms. New York.
    2. Davis, G.L. 1966. Systematic embryology of the angiosperms. New York.
    3. Johri, B.M. (ed.). 1984. Embryology of angiosperms. Berlin.
    4. --, K.B. Ambegaokar, & P.S. Srivastava. 1992. Comparative embryology of angiosperms. 2 vols. Berlin.
    5. Kapil, R.N. & A.K. Bhatnagar. 1991. Embryological evidence in angiosperm classification and phylogeny. Bot. Jahrb. Syst. 113: 309-338.
    6. Raghavan, V. 1986. Embryogenesis in angiosperms: A developmental and experimental study. Cambridge.v
    7. Takhtajan, A.L. (ed.). 1985-1991. Sravnitel'naia anatomiia semian. 3 vols. (to date). St. Petersburg.
    "double fertilization"
    a process of double fertilization first evolved in a common ancestor to the gnetophytes and the angiosperms. The second fertilization product was diploid and yielded a supernumerary embryo. Subsequent evolution led to the establishment of an embryo-nourishing triploid endosperm. Work done by William (Ned) Friedman
    Ephedra
    earliest flowering plants displayed an ab initio cellular pattern of endosperm development and not free nuclear as previously assumed.
    1. Friedman, W.E. 1990a. Double fertilization in Ephedra, a non-flowering seed plant: Its bearing on the origin of angiosperms. Science 247: 951-954.
    2. --. 1990b. Sexual reproduction in Ephedra nevadensis (Ephedraceae): Further evidence of double fertilization in a nonflowering seed plant. Amer. J. Bot. 77: 1582-1598.
    3. --. 1992a. Double fertilization in nonflowering seed plants and its relevance to the origin of flowering plants. Intern. Rev. Cytol. 140: 319-355.
    4. --. 1992b. Evidence of a pre-angiosperm origin of endosperm: Implications for the evolution of flowering plants. Science 255: 336-339.v
    5. --. 1993. The evolutionary history of the seed plant male gametophyte. Trends Ecol. Evol. 8: 15-21.
    6. --. 1994. The evolution of embryogeny in seed plants and the developmental origin and early history of endos-perm. Amer. J. Bot. 81: 1468-1486.
    embryological features common in angiosperms
    1. 1. four microsporangia
    2. 2. two-celled pollen grains
    3. 3. eight-nucleate embryo sac
    4. 4. nuclear endosperm
    Cytotaxonomy
    cytological evidence
    chromosome number - need a review?
    chromosome shape and size
    stages of mitosis and meiosis - a pictorial review
    cytogenetics
    G. Ledyard Stebbins (1906- )
    1. Stebbins, G.L. 1971. Chromosomal evolution in higher plants. Boston.
    haploid, diploid, tetraploid, octoploid
    Haplopappus
    Poa
    Eriogonum
    polyploids, polyploidy
    aneuploids, aneuploidy
    homoploids, homoploidy
    sporophytic (n) number
    somatic (2n) number
    base number (x)
    Pinus n= 12
    Aster (s.l.) x= 4, 5, 8, 9
    Aster (s.s.) x= 9
    Machaeranthera x= 4 (see right)
    Virgulus x= 5
    Symphyotrichum x= 8
    Brassica n= 6, 7, 8, 9, 10
    autoploid: a polyploid organism that arose by a multiplication of one basic set of chromosomes
    autoploids, autopolyploidy
    alloploid: a polyploid organism that arose by the combination of genetically distinct chromosome sets
    alloploids, allopolyploidy
    autotetraploid
    amphidiploid, amphidiploidy
    genomes
    chromosome compliments
    A x= 10
    AA (2n= 20) x AA (2n= 20)
    doubling of same genomic chromosomes results in an autotetraploid, an autopolyploid condition
    AA (2n= 20) doubled to AAAA (2n= 40) or 4x= 40
    AA (2n= 20) x BB (2n= 20)
    AB (2n= 20), usually sterile, doubled to AABB (2n= 40 or 4x= 40), fully fertile doubling of amphidiploid genomic chromosomes resulting in an autoalloploidy
    Agave (right), Yucca n= 30
    five large and 25 small chromosomes
    gross morphology vs. chromosome number
    Centaurium namophilum var. nevadense
    n= 17 and C. exaltatum n= 40

    Ultrastructure
    electron microscopy
    transmission electron microscope (TEM)
    scanning electron microscope (SEM)
    H.-Dietmar Behnke
    1. Behnke & W. Barthlott. 1983. "New evidence from the ultrastructural and micromorphological fields in angiosperm classification." Nordic J. Bot. 3: 43-66.
    Palynology
    palynologists
    pollen and spores
    pollen wall structure, polarity, symmetry, shape and size
    James W. Walker (1943- )
    monosulcate: cycads, ferns, conifers, primitive dicotyledons and most monocotyledons
    germinal furrow
    aperture
    tricolpate: advanced dicotyledons
    a multitude of pollen types
    1. Erdtman, G. 1969. Handbook of palynology: Morphology-taxonomy-ecology: An introduction to the study of pollen grains and spores. New York.
    2. Nair, P.K.K. 1970. Pollen morphology of angiosperms: An historical and phylogenetic study. Lucknow.
    3. Nowicke, J. 1979. Pollen morphology: The potential influence in higher order systematics. Ann. Missouri Bot. Gard. 66: 633-700.
    4. Nilsson, S. & J. Praglowski (eds.). 1992. Erdtman's Handbook of palynology, ed. 2. Copenhagen.
    5. Shivanna, K.R. & B.M. Johri. 1985. The angiosperm pollen: Structure and function. New Dehli.
    6. Skvarla, J.J., J.R. Rowley & W.F. Chissoe. 1988. Adaptability of scanning electron microscopy to studies of pollen morphology. Aliso 12: 119-175.
    Paleobotany - see "The value of fossil collecitons" by Warren D. Allmon and Terry Pulton
    microfossils, macrofossils
    first land plants belong to Bryophyta
    late Ordovician possibly 450-470 mybp during a period of extensive glaciation and mass extinction
    evolved from a charophycean ancestry and most closely resembled thalloid liverworts
    Todd J. Cooke recently demonstrated that the Charales (Chara, Nitella) are in fact land plant that never formed an embryo and thus these genera are not themselves the origin of land plants
    first vascular plants - first appeared in the upper Silurian about 430 mybp (originally found in Australia, now known from Bolivia), possibly of a bryophyte origin
    lacked roots and leaves but had a symbiotic association (mycorrhizal) with fungi
    1. Graham, L.E. 1993. Origin of land plants. New York
    2. --. 1996. Green algae to land plants: An evolutionary transition. J. Pl. Res. 109: 241-251.
    3. --, C. Delwiche & B.D. Misler. 1991. Phylogenetic connection between the "green algaae" and the "bryophytes". Advances Bryol. 4: 213-244.
    4. Kranz, H.D., D. Miks, M.-L. Siegler, I. Capesius, W. Sensen & V.A.R. Huss. 1995. The origin of land plants: Phylogenetic relationships among charophytes, bryophytes, and vascular plants inferred from complete small-subunit ribosomal RNA gene sequences. J. Molec. Evol. 41: 74-84.
    5. Manhart, J.R. 1994. Phylogenetic analysis of green plant rbcL sequences. Molec. Phylogenetics Evol. 3: 114-127.
    6. Mishler, B.D., L.A. Lewis, M.A. Buchheim, K.S. Renzaglia, D.J. Garbary, C.F. Delwiche, F.W. Zechman, T.S. Kantz & R.L. Chapman. 1994. Phylogenetic relationships of the "green algae" and "bryophytes". Ann. Missouri Bot. Gard. 81: 451-483.
    Rhyniophyta - one of the rhynie plants from Scotland - see this site on microspores
    Zosterophyllophyta
    Trimerophytophyta
    all other major divisions still extant
    Devonian
    major extinction events mark the boundaries of most of the major geologic epochs, e.g., end of the Paleozoic (some 245 mybp) and the Cretaceous (some 65 mybp)
    Raup & Sepkoski suggest that major extinction events are cyclic occurring about ever 26 my.
    1. Alvarez, L.W., W. Alvarez, F. Asaro & H.V. Michel. 1980. Extraterrestrial cause for the Cretaceous-Tertiary extinction. Science 208: 1095-1108.
    2. Raup, D.M. & G.E. Boyajian. 1988. Patterns of generic extinction in the fossil record. Paleobiology 14: 109-125.
    3. -- & J.J. Sepkoski. 1984. Periodicity of extinction in the geologic past. Proc. Natl. Acad. Sci. U.S.A. 81: 801-805.
    4. ----. 1988. Testing for periodicity of extinction. Science 241: 94-96.
    5. Stanley, S.M. & X. Yang. 1994. A double mass extinction at the end of the Paleozoic Era. Science 266: 1340-1344.
    DNA from Miocene Taxodium, Magnolia, Celtis and Ulmus
    some question if the sample DNA is bacterial or truly from the named organism
    1. Austin, J.J., A.B. Smith & R.H. Thomas. 1997. Palaeontology in a molecular world: The search for authentic ancient DNA. Trends Ecol. Evol. 12: 303-306.
    2. Giannasi, D.E. & K.J. Niklas. 1977. Flavonoid and other chemical constituents of fossil Miocene Celtis and Ulmus (Succor Creek Flora). Science 197: 765-767.
    3. Golenberg, E.M., D.E. Giannasi, M.E. Clegg, C.J. Smiley, M. Durbin, D. Henderson & G. Zirawski. 1990. Chloroplast DNA sequence from a Miocene Magnolia species. Nature 344: 656-658.
    4. Sidow, A., A.C. Wilson & S. Pääbo. 1991. Bacterial DNA in Clarkia fossils. Trans. Philos. Soc. London, ser. B, 333: 429-433.
    5. Soltis, P.S., D.E. Soltis & C.J. Smiley. 1992. An rbcL sequence from a Miocene Taxodium (bald cypress). Proc. Natl. Acad. Sci. U.S.A. 89: 449-451.
    Ecology
    Harvey M. Hall (1874-1932)
    Jens Clausen, David D. Keck, William Hiesey
    "Experimental studies on the nature of species" In four parts published by Carnegie Institution from 1940-1958
    genetic vs. environmental established variation
    Achillea lanulosa - see also the introductory remarks - time to do that German
    1. Clausen, J. 1951. Stages in the evolution of plant species. Ithaca.
    adaptation - see some recent abstracts and review the PBIO 100 notes
    1. Grant, V. 1963. The origin of adaptations. New York
    ecotypic variation
    edaphic (soil) specialization
    effect of habitat on hybridization
    plant-herbivore interactions
    seed-dispersal mechanisms
    seedling establishment
    function of plant structure
    reproductive isolating mechanisms
    edaphic
    Arthur R. Kruckeberg (1920- )
    serpentine
    local speciation and endemism
    paleoclimates
    a useful but dated glossary of terms

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