Flashcards in Development of classification Deck (47):
Theophrastus, Forms systems
￼Theophrastus classified all plants on the basis of the following characters:
• trees, shrubs, subshrubs, herbs
• annuals, biennials, perennials
• flowering versus nonflowering
• superior ovary versus inferior ovaries.
• free petals (polypetaly) versus fused petals (gamopetaly).
Caius Plinius Secundus, “Pliny the Elder”
De Materia Medica
Roman military surgeon
For 1500 years this was universally considered the major work on plants.
-first to recognize, on the basis of stem structure, the differences between monocots and dicots
Herbarium Vivae Eicones
-His work became known as an herbal.
-took most of its information from the writings of Theophrastus, Dioscorides, and Pliny
De Historia Stirpium
-illustrated by woodcuts
his Herbal, the first botanical work in English
“Father of English Botany.”
Rariorum Plantarum Historia
best known for “inventing” or at least making popular the use of the herbarium
De Plantis Libri
-First Plant Taxonomist
Caesalpino classified plants based on:
habit (trees, shrubs, herbs)
• fruit type
• ovary (superior versus inferior)
• root system (tap versus fibrous)
• presence or absence of latex
• number of locules in an ovary
Pinax Theatri Botanica
first botanist to distinguish between genus and species
Historia Plantarum Universalis
￼Methodus Plantarum Nova
John Ray Classification system based on:
habit (woody versus herbaceous)
• dicots versus monocots
• fruit types
• leaf types
• flower features
-He was the first to use families in the sense that they are used today
Institutiones Rei Herbariae
Joseph Pitton de Tournefort
-Father of the Genus Concept.”
Tournefort classified flowers based on:
petals versus no petals (apetalous)
• petals (free versus united)
• corolla shape (regular versus irregular)
-SEXUAL SYSTEM OF PLANTS
-“Father of Taxonomy.”
-Systema Naturae (1735), Genera Plantarum (1737), and Hortus Cliffortianus (1738).
-￼Linnaeus assisted Johannes F. Gronovius (1686-1762) in describing the plants collected by John Clayton (1686-1773) in Virginia in Flora Virginica (1739, 1743).
￼Species Plantarum's greatest significance lies in the consistent use of the binomial system of nomenclature, that is, a single generic name along with a single specific epithet
￼Linnaeus arranged this book according to the sexual system outlined in Systema Naturae. He divided the plants into 24 classes based largely on the number, union and length of stamens.
The classes were divided into orders based on the number of styles in each flower. Although some related genera were associated in this “Sexual System,” it was still an artificial classification.
￼EARLY “NATURAL” SYSTEMS
The development of a classification system reflecting natural relationships became a major focus of botanical activity. In its original context, the natural system was designed to reflect God's plan of creation and not one of lineages.
arranged plants into groups similar to our orders and families
-Familles des Plantes
￼Adanson emphasized that many characters should be used in a classification scheme, and that equal weight should be placed on each unless detailed studies showed that some were more important taxonomically. This is called the empirical approach
De Jussieu family
Antoine, Bernard, Joseph, Antoine-Laurent (major step towards natural plant families)
￼Antoine-Laurent ￼divided plants into three major groups
Acotyledones (cryptogams and a few misplaced monocots)
• Monocotyledones (monocots)
• Dicotyledones (dicots and gymnosperms).
De Candolle family
Augustin Pyramus De Candolle, Alphonse
-They divided plants into two major groups:
• Cellulares (nonvascular)
• Vasculares (vascular)
-began dicots with Ranunculaceae
George Bentham and Joseph Dalton Hooker
-The dicots were divided into three groups:
• Polypetalae (free petals)
• Gamopetalae (fused petals)
• Monochlamydeae (apetalous)
-species concepts were based on the idea that species are fixed entities, unchanged through time and placed on the earth by the Creator.
British herbaria, such as Kew and the British Museum, are still arranged according to the Bentham and Hooker system
￼POST-DARWINIAN “NATURAL” SYSTEMS
Darwin's Origin of Species (1859) did much to alter the basic concepts used in determining relationships. Attempts to follow his principles resulted in systems that arranged natural groups in a phylogenetic (evolutionary) sequence progressing from the simplest (most primitive) to the more complex (most advanced).
￼August Wilhelm Eichler system
based his system on morphological information
-For example, his system divided the non-seed plants into the:
• Thallophyta (liverworts)
• Bryophyta (mosses)
• Pteridophyta (ferns and allies)
System still used in most non-British herbaria.
Adolph Engler (1844-1930) and Karl Prantl (1849- 1893), and is referred to as the Englerian School.
-now considered incorrect￼ (equated “simple” with “primitive)
Monocots preceded the dicots in this system, and dicots were divided into the:
• Archichlamydeae (free petals or no petals) • Metachlamydeae (fused petals)
-Engler considered plants with simple, unisexual flowers to be primitive. The first group of dicots were the Amentiferae (wind- pollinated, catkin-bearing plants and their relatives). Modern families with these traits are Betulaceae, Fagaceae, and Juglandaceae.
Outlines of Plant Phylaflowering plants began with the Magnoliaceae- Ranunculaceae complex.
-This complex was comprised of primarily insect-pollinated plants. This group gave rise to the other dicots and to the monocots. He considered the wind pollinated Amentiferous families to be secondarily reduced.
￼￼￼￼￼￼￼￼￼￼Bessey’s system, which was really a modified Bentham and Hooker classification, was based on a set of dicta or concepts of primitive features found in ancient plants versus the advanced characters of more recently evolved plants.
woody preceded herbs, vines, and climbers
• perennials preceded biennials and annuals
• vascular bundles in a ring (dicots) preceded vascular bundles scattered (monocots)
• alternate leaves preceded opposite or whorled leaves
• simple leaves preceded compound leaves
• bisexual flowers preceded unisexual flowers
-many-parted flowers preceded few-parted flowers
• actinomorphic (regular) flowers preceded zygomorphic (irregular) flowers
• separate perianth parts preceded fused perianth parts
• flowers with petals usually preceded apetalous ones
• many separate stamens preceded few or united stamens
-hypogyny (superior ovary) preceded epigyny (inferior ovary)
• generally, numerous separate carpels preceded fewer, fused carpels
• pollen grains with one pore preceded those with three pores
• axile placentation preceded free central placentation
• simple fruits preceded aggregate fruits
attempted to show the interrationships among the various orders he recognized.
The Families of Flowering Plants￼ provided ready keys and descriptions to the families.
￼Hutchinson divided the angiosperms into
• Herbaceae Dicotyledones (herbaceous dicots)
• Lignosae Dicotyledones (woody dicots)
-He suggested that monocots were derived from certain primitive herbaceous dicots (Ranales), and all other herbaceous dicots were also derived from the Ranales
-￼The woody dicots were said to be derived from the Magnoliales
-major flaw was this division of the dicots into a woody versus herbaceous lines
-but excellent family descriptions
￼CONTEMPORARY CLASSIFICATION SYSTEMS
Takhtajan, cronquist, Thorne, and dalgren
￼Takhtajan described the earliest angiosperms as follows:
• small woody plants
• leaves simple, entire, and pinnately veined
• flowers solitary, of moderate size, arrangement terminal and axillary
-flowers actinomorphic, bisexual
• numerous sepals, petals, stamens, and carpels
• stamens leaflike, pollen monosulcate
• carpels unsealed, conduplicate with the stigmatic surface along the margin
These would have been similar to members of the present-day Magnoliaceae.
Magnoliales was the most primitive group of flowering plants, and all others evolved from it. He believed that the monocots evolved from a precursor of the order Nymphaeales
recognized the classes Magnoliopsida and Liliopsida in the Phylum Magnoliophyta
agreed with Takhtajan but Cronquist recognized 11 subclasses (instead of 10)
-Cronquist included Takhtajan's Ranunculidae in his own Magnoliidae. In addition, he divided Takhtajan's Liliidae into his Liliidae, Commelinidae, and Zingiberidae.
57 orders and 395 families in the two subclasses Dicotyledoneae and Monocotyledoneae
- 'phylogenetic shrub'
placed all of the angiosperms in Class Magnoliopsida
-He did not recognize subclasses in the same sense that Cronquist and Takhtajan did, although he did distinguish between the dicots (subclass Magnoliidae) and monocots (subclass Liliidae) as distinct groups
According to the englerian school dicotyledons began with: