Taxonomy of Flowering Plants B 204, BT 204
Dr. Ahmad Mekawy Plant Taxonomy
Dr. Ahmad Mekawy I. Why do we love plants? What makes them so special? A. Plants are: 1. Beautiful 2. Unusual 3. Complex 4. Diverse 5. They feed us! 6. They are the lungs of the earth 7. They have charted the course of human settlement on earth (grasses). 8. They put a roof over our heads 9. Many have greatly impacted history
Pyrola asarifolia (Wintergreen) http://www.pbase.com/rodg/western_washington_native_plants II. People and Plants A. We affect each other – how? 1. We can’t live without them!
2. They exchange CO2 for O2 – mitigates greenhouse effect. 3. We destroy, pollute their habitat, causing extinction 4. They can destroy habitat, harming our economy – invasive plants!! 5. We can alter the course of their evolution, through: a. Gm crops, conservation genetics, selective breeding
B. Plants are sources 1. of food. 2. of paper. 3. of fibers. 4. of medicines. C. Life without 1. paper. 3. cotton. 2. roses. 4. linen. 5. wood. 6. pepper.
7. cinnamon. 9. sugar. 8. vanilla. 10. etcetera. 11. Dark Chocolate. Phylogeny & Systematics A. Definitions 1. Systematics = the study of biological diversity in an evolutionary context, encompassing taxonomy and involving the reconstruction of phylogenetic history. Systematics = taxonomy + phylogeny 2. Phylogeny = the evolutionary history of a species or group of related species 3. Taxonomy = the science of naming and classifying organisms B. Goals of Plant Taxonomy
1. Develop a natural system of classification, in which closely related organisms are classified together
2. Assigning names on the basis of evolutionary relationships. C. History 1. Carolus Linnaeus (1707-1778) a. Credited with the use of scientific names. b. A professor of natural history at the University of Uppsala in Sweden. c. He was the primary professor for 180 students, many of whom became excellent botanists and world travelers. d. He created a large number of genera and placed every species into one genus or another. e. Each species had both a genus name and a species name, the binomial system. D. Criteria for Grouping?
Taxonomy today still employs the hierarchical system of classification: a. Domain h. Species
b. Kingdom g. Genus
c. Phylum f. Family
d. Class e. Order 3. Levels of Taxonomic Categories Dicot Monocot • Domain Eukarya Eukarya • Kingdom Plantae Plantae • Phylum Anthophyta Anthophyta • Class Magnoliopsida Liliopsida • Order Fabales Liliales • Family Fabaceae Liliaceae • Genus Lupinus Hymenocaulis • Species Lupinus texensis Hymenocaulis carbaea Texas bluebonnet Spider lily • Scientific names are necessary because the same common name is used for different plants in different areas of the world.
• Latin is the language used for scientific classification.
• Scientific expression
Genus species authority:
Penstemon fruticosis (Pursh) Greene Divisions
• The four most important divisions of the plant kingdom are…. – Thallophites – Bryophytes – Pteriophytes – Spermatophytes Spermatophytes
• Includes flowering or seed-bearing plants. • The two subdivisions are…. – Gymnosperms – Angiosperms Plant Kingdom
Non-flowering Flowering Plants Plants . 3 groups Non - flowering Plants
Mosses Ferns Gymnosperms
Do NOT produce flowers Examples of Mosses Spore-producing capsule
spores Characteristics of Mosses
.Simplest plants .No true roots, No vascular tissues (no transport) .Simple stems & leaves .Have rhizoids for anchorage .Spores from capsules (wind-dispersal) .Damp terrestrial land
A leaf (finely divided into small parts) underground stem root
Characteristics of Ferns .roots, feathery leaves & underground stems .have vascular tissues (transport & support)
.Spore-producing organ on the underside of leaves (reproduction) .Damp & shady places needle-shaped leaves Male cones Female cones (in clusters) (scattered) Characteristics of Gymnosperms .tall evergreen trees .roots, woody stems .needle-shaped leaves .vascular tissues (transport) .cones with reproductive structures .naked seeds in female cones .dry places . 2 groups Flowering Plants
Monocotyledons Dicotyledons . roots, stems, leaves . vascular tissues (transport) . flowers, fruits (contain seeds) Monocotyledons
Parallel veins Characteristics of Monocotyledons . one seed-leaf . leaves have parallel veins . herbaceous plants . e.g. grass, maize Dicotyledons
Veins in network Characteristics of Dicotyledons . two seed-leaves . leaves have veins in network . e.g. trees, sunflower, rose Plant Classification Plants
Non-flowering Flowering
Spore- Naked 1 seed- 2 seed- bearing seeds leaf leaves Monocots Dicots Gymnosperms No with roots roots Mosses Ferns Identifying Plants
Flowers are the main criteria for identifying species in this division. VI. Basic plant parts A. Generalized
The parts of a flower are typically attached to the: 1. receptacle – the portion of the pedicel upon which the flower parts are borne. 2. pedicel – the stalk of a single flower. It attaches the flower to the plant. 3. Whorls: a. The outermost whorl is the calyx – a collective term for all of the sepals. Sepal – a typically green and leaf-like structure. b. The next whorl is the corolla – a collective term for all of the petals. Petal – a typically colored or white, delicate structure. Petals function to attract pollinators. c. The third whorl is the androecium = collective term for the male flower parts. Each part is called a stamen. The stamen is composed of: i. Filament – a stalk attached to the recepticle ii. Anther – a collection of pollen sacs that sits on top of the filament. d. The innermost whorl is the gynoecium – a collective term for the female flower parts. Each part is called a pistil (or carpel). Consisting of: i. Stigma – portion of the pistil receptive to pollen ii. Style – portion of the pistil connecting the ovary & stigma iii. Ovary – the base of the pistil, contains the ovules. (Mature ovules are seeds and mature ovary is the fruit) 4. Perianth = the calyx + the corolla The Perianth may be: a. Polypetalous or distinct = petals aren’t fused to each other. b. Gamopetalous = petals are fused to each other c. Polysepalous = sepals are not fused d. Gamosepalous = sepals are fused g. An important trait that must be determined for identification purposes: ovary position Superior ovary = hypogynous flower = the perianth parts & stamens are attached down to the ovary to the receptacle Inferior ovary = epigynous flower = the perianth parts & stamens are attached above the ovary wall and they appear to arise from the top of the ovary Half-inferior ovary = perigynous flower = the perianth parts & stamens attached to the same point of ovary at the receptacle
Hypanthium is the fusion of two or more floral parts. 5. Position of Inflorescence Types: Inflorescence = the entire flowering part of a plant ** Page 176-177 of Harris a. Spike = single sessile flowers on rachis (flowering stalk) b. Raceme = single flowers on pedicels along the rachis c. Panicle = a much-branched inflorescence d. Solitary flower e. Many more!!
6. More terms!!! a. Distinct = parts not fused b. Connate = fusion of like parts c. Adnate = fusion of unlike parts d. Complete flower = a flower that has a calyx, corolla, stamens and pistil e. Incomplete flower = lacks one of the whorls of flower parts f. Perfect flower = has stamens & pistils (bisexual) g. Imperfect flower = lacks either stamens or pistils (unisexual) D. Fruit 1. Definition = a ripened ovary and any other structures that are attached and ripen with it. a. the primary function of a fruit is seed dispersal b. pages 205-206 of Harris 2. Types: Name some? a. Fleshy b. Dry
Name some? Get out and smell the nature!
The parts of a flower are typically attached to the: 1. receptacle – the portion of the pedicel upon which the flower parts are borne. 2. pedicel – the stalk of a single flower. It attaches the flower to the plant. 3. Whorls: a. The outermost whorl is the calyx – a collective term for all of the sepals. Sepal – a typically green and leaf-like structure. b. The next whorl is the corolla – a collective term for all of the petals. Petal – a typically colored or white, delicate structure. Petals function to attract pollinators. c. The third whorl is the androecium = collective term for the male flower parts. Each part is called a stamen. The stamen is composed of: i. Filament – a stalk attached to the recepticle ii. Anther – a collection of pollen sacs that sits on top of the filament.
d. The innermost whorl is the gynoecium – a collective term for the female flower parts. Each part is called a pistil (or carpel). Consisting of: i. Stigma – portion of the pistil receptive to pollen ii. Style – portion of the pistil connecting the ovary & stigma iii. Ovary – the base of the pistil, contains the ovules. (Mature ovules are seeds and mature ovary is the fruit) 4. Perianth = the calyx + the corolla The Perianth may be: a. Polypetalous or distinct = petals aren’t fused to each other. b. Gamopetalous = petals are fused to each other c. Polysepalous = sepals are not fused d. Gamosepalous = sepals are fused • An important trait that must be determined for identification purposes: ovary position Superior ovary = hypogynous flower = the perianth parts & stamens are attached down to the ovary to the receptacle (Petunia sp. flower) Inferior ovary = epigynous flower = the perianth parts & stamens are attached above the ovary wall and they appear to arise from the top of the ovary (Apple flower) Half-inferior ovary = perigynous flower = the perianth parts & stamens attached to the same point of ovary at the receptacle (Roses and Apricot flowers)
Monoec ious Ex: Ricinus
Ex: Palmae
Gynandrous stamens
Plant families Dicotyledonae
Dialypetalae Archichlamydeae Malvaceae -- the mallow family
Habit herbs, shrubs, or trees; often with mucilaginous sap Inflorescences various, usually determinate Special floral characteristics Calyx 5 sepals, often subtended by an epicalyx Androecium many stamens, monadelphous stamens Fruit = schizocarp (mericarps) or a capsule Floral formula:
K 5 C 5 A () G (3- ) axile
Malvaceae– common plants
Hibiscus sabdariffa (Roselle)
Hibiscus esculentus (Okra) Malva parviflora (Mallow)
Gossypium hirsutum (Cotton) Brassicaceae -- the mustard family
Habit herbs (sometimes woody or even shrubby) Inflorescences racemes Special floral characteristics flowers with 4 cruciform petals and sepals, Tetradynamous stamens: 4 with long filaments and 2 with short filaments Fruit = silicle, silique, sometimes indehiscent Floral formula:
K 2+2 C 4 A 2+4 G ( 2 ) parietal
Brassicaceae – common plants
Brassica (cabbage, cauliflower,, broccoli, turnip, etc.).
Brassica oleracea (cabbage)
Raphanus sativus (radish) Brassica rapa (turnip)
Eruca sativa Fabaceae-- the legume family
Habit herbs, shrubs or trees, generally climbers Inflorescences racemes Special floral characteristics Corolla papilionaceous, Petals 5, large – the standard; two wings; and the keel. stamens 10 diadelphous fruit legume. Floral formula:
% K 5 C 1+2+(2) A 1+(9) G (1) marginal
Fabaceae– common plants
Vicia faba Arachis hypogaea (faba bean)
Cicer arietinum
Lens esculentus Pisum sativum (Peas) Lupinus termis (Lupin)
Phaseolus vulgaris (common bean) Papaveraceae -- the Poppy family
Habit herbs, shrubs, rarely trees; often with milky sap (The plants have latex which may be white or yellowish in colour) Inflorescences Solitary terminal (Papaver), axillary raceme and panicles. Fruit capsule, dehiscence by valves or pores, rarely nut. Floral formula:
K 2 C 2+2 A () G (2- ) Parietal
Papaveraceae – common plants Papaver somniferum Argemon mixicana Opium Poppy
Papaver rhoeas Common Poppy Milky sap Common Poppy Papaver rhoeas Common Poppy
Papaver somniferum Opium Poppy Geraniaceae
Habit Annual herbs or under shrubs very rarely shrubs. Plants covered with simple or glandular hairs Androecium sometimes some stamens reduced to antherless or scale-like staminodes. Inflorescences Cymose (polychasium) or solitary. Fruit Capsule or mericarps. Floral formula:
% K 5 C 5 A (3·+7) G (5 ) Axile Ornamentals Different species and hybrids of Geranium and Pelargonium are cultivated in gardens for their showy and aromatic flowers.
Pelargonium graveolens Erodium geranium Linaceae
Habit Annual or perennial herbs, hook climbing shrubs or undershrub’s.
Androecium stamens 10 usually, outer whorl being reduced to staminodes and inner one united at the base to form a ring. Inflorescences Racemose or cymose, scorpioid (Flax)
Fruit Septicidal capsule, surrounded at the base by persistent calyx. Floral formula:
K 5 C 5 A (5·+5) G (5 ) Axile
Linum usitatissimum Linum grandiflorum Tropaeolaceae
Habit Herbs usually with soft prostrate stem, often climbing with the help of long petioles. . Sepals 5, usually colored, the posterior is prolonged into a spur Petals 5, free, clawed Androecium Stamens 8 in 2 whorls Inflorescences Solitary flowers Fruit 3-seeded schizocarp Floral formula:
% K 5 C 5 A 4+4 G (3 ) Axile
Tropaeolum majus
Fruit Spur Rutaceae
Habit Shrubs or trees, rarely herbs, Plants has oil glands. Inflorescences Racemose or cymose, or the flowers solitary. Flower An annular disc or a gynophore is present above the androecium. Fruit Septicidal capsule. Floral formula:
K 4 C 4 A 4+4 G (4) Axile
Citrus aurantifolia Citrus sinensis
Citrus limonia Citrus nobilis Ruta graveolens Umbelliferae-- Apiaceae
Habit plants are mostly herbs which may be annual, biennial or perennial Inflorescence Simple or compound umbel. Flower Epigynous. Fruit Schizocarpic (oil ducts). Floral formula:
K 5 C 5 A 5 G (2) Apical
Anethum graveolens Anis Apium graveolens celery Cuminum cyminum Coriandrum sativum Petroselinum sativum Daucus carota Parsley Caryophyllaceae
Habit Generally herbaceous plants or undershrub Inflorescence Cymose type Flower Sepals persistent Fruit Nut or achene, or capsule opening by apical valves or teeth
Floral formula:
K (5) C 5 A 5+5 G (2-5) Central
Dianthus caryophyllus Silene vulgaris Gypsophilla elegans Sympetalae
fused petals Apocynaceae
Habit Herbs, shrubs, tree (Alstonia) with latex. Inflorescence Cymose type, or axillary Flower Corolla Petals 5, gamopetalous forming a corolla tube which may be long or short, corona present Fruit A drupe (Thevetia), berry (Carissa), follicle (Nerium, Amsonia).
Floral formula:
K (5) C (5) A 4-5 G (2) Axile
Vinca rosea Catharanthus roseus Nerium oleander Thevetia peruviana Convolvulaceae
Habit Herbs (Convolvulus), shrubs and climbing (Ipomoea), the plants may be xerophytic, hydrophytic or parasitic (Cuscuta)
Inflorescence Solitary axillary (Convolvulus) or cymes.
Fruit Capsule (Convolvulus, Cuscuta) or berry Floral formula:
K 5 C (5) A 5 G (2) Axile
Ipomea batatas Convolvulus arvensis
Ipomea cairica Cuscuta chinensis Parasitic Solanaceae
Habit Mostly herbs (Petunia), shrubs and trees
Inflorescence Solitary axillary, umbellate cyme, or helicoid cyme in Solanum Fruit Capsule or berry
Floral formula:
K (5) C (5) A 5 G (2) Axile
Solanum tuberosum
Solanum melongena Solanum lycopersicum Datura inoxia Nicotiana tabacum Petunia hybrida Scrphulariaceae
Habit: Mostly herbs (Antirrhinum) or shrubs rarely trees Inflorescence: Cymose or racemose, it may be spike Fruit: A capsule or berry Floral formula:
% K 5 C (5) A 4 G (2) Axile
Antirrhinum majus Linaria vulgaris (Snapdragon or dog flower)
Digitalis purpurea (Foxglove) Lamiaceae
Habit: Plants are mostly aromatic herbs or shrubs
Inflorescence: Dichasial cymes
Sepals and petals 5,fused, bilabiate
Fruit: Usually schizocarpic, or achenes or nutlets.
Floral formula:
% K ( 3+2) C (2+3) A 2 G (2) Axile
Lavandula vera
Ocimum basilicum Mentha piperita Bignoniaceae
Habit: Mostly trees or shrubs; often climbing or twining vine, rarely herbs
Inflorescence: Usually dichasial cyme
Stamens 4 epipetalous, posterior staminode
Fruit: Capsule or berry
Floral formula:
· % K ( 5) C (5) A 4+1 G (2) Axile
Bignonia venusta Jacaranda acutifolia Tecoma stans Asteraceae - Compositae
Habit: Herbs, shrubs and rarely trees, Many of the plants are xerophytes
Inflorescence: Capitulum
On the basis of form of flowers the heads are of three types:
1. Heterogamous or radiate heads. The outer or ray-florets are ligulate and zygomorphic and inner or disc-florets tubular and actinomorphic e.g. Helianthus.
2. Homogamous-rayed or ligulate heads. All the flowers in the head are ligulate, zygomorphic and alike; e.g. Sonchus.
3. Homogamous-non-rayed or discoid heads. All the flowers are tubular, actinomorphic and alike, e.g., Ageratum. Homogamous-rayed or ligulate heads Homogamous-non-rayed or discoid heads
Heterogamous or radiate heads Inflorescence: Capitulum
Ray-florets:
Zygomorphic, ligulate, female and sometimes bisexual, epigynous.
Calyx: Modified into pappus or absent or scale-like.
Corolla: Petals 5, gamopetalous, highly coloured, ligulate.
Fruit: cypsela
Floral formula:
% K C A G ♀ · (5) · (1) Basal Disc-florets:
Actinomorphic, tubular, bisexual, epigynous.
Calyx: Modified into pappus or scale-like.
Corolla: Petals 5, gamopetalous, coloured, tubular.
Androecium: Stamens 5, epipetalous, syngenesious,
Fruit: cypsela
Floral formula: K C A G · (5) (5) (1) Basal Disk-floret Ray-floret Silybum marianum Matricaria chamomilla Artemisia judaica
Helianthus annuus Monocotyledoneae Liliaceae-- the Lily family
Habit herbs rarely shrubs, stem underground rhizome, corm or bulb Inflorescences racemes or cymose Special floral characteristics Perianth (Calyx + Corolla) colored or petaloid fruit berry or capsule. Floral formula:
P 3+3 A 3+3 G (3) axile
Liliaceae– common plants
Allium cepa (onion)
Allium sativum (Garlic) Lilium sp (Lily)
Asparagus officinalis Poaceae (Graminae)- Grass family
Habit Herbs, annuals or perennials or shrubs, sometimes tree like
Inflorescences Compound spike Special floral characteristics Perianth represented by membranous scales called the lodicules (Palea and lemma)
fruit Caryopsis Floral formula:
3 (1) % P · A G basal
Oryza sativa (Rice) Hordeum vulgare (Barley) Triticum aesativum (wheat) zea mays Maize
Saccharum officinarum Sugarcane Arecaceae- (Palmae) Habit Large unbranched trees (Phoenix), shrubs or garden palms
Inflorescences It is simple or compound, spike or branched panicle, spadix
Special floral characteristics Plant may be monoecious or dioecious fruit Usually a berry, (Phoenix); drupe (Cocos nucifera).
Floral formula: ♀ P (3)+3 A . G (1) apical
♂ P (3)+3 A 6 G .
Phoenix dactylifera Cocos nucifera Best wishes