I.  Fats and Oils
  A. Background Information.
    1. Triglycerides:  glycerol plus fatty acids esterified by 
         single carboxyl group to hydroxyl
    2. Fat: Glycerol plus 3 different fatty acids.  Solid at 
         room temperatures.
      a. Fatty Acids: even numbers of carbons, especially 16 
           and 18 carbons
      b. Melting point rises with length of fatty acid and 
           with the extent of saturation
      c. Solid fats have saturated fatty acids
    3. Oils: Glycerol plus fatty acids (usually 18 carbons) 
        with one to three double bonds.  Liquids at room 
      a. Lower melting points
      b. Important plant oils from seeds:  cotton, corn, 
            peanuts, soybean, canola, and coconut
      c. Oils from fruits: olive
      d. Oils contain fatty acids with 18 carbons 
           and one to three double bonds
        (1) Oleic 18:1, Linoleic 18:2, Linolenic 18:3
    4. Most abundant saturated fatty acid is palmitic 16:0
    5. Coconut fat:  Lauric acid 12:0
  B. Distribution and Importance of Fats
    1. Fat storage is rare in leaves, stems, and roots
    2. Fat storage is high in seeds and fruits
      a. Fruits: olive and avocado
    3. Angiosperms: fats concentrated in endosperm or 
         cotyledon of seeds.
    4. Gymnosperms: fats stored in female gametophyte of seed.
    5. Seeds store fats because fats contain a greater amount 
        of energy stored per unit volume than carbohydrates.  
        Carbohydrates also associate with larger volumes of 
        water than do fats.  Thus the size of the seed will 
        determine the type of storage compound.
      a. Large seeds:  store carbohydrate
      b. Small seeds:  store fats
    6. Fats stored in specialized bodies in cytosol
      a. Oleosomes: lipid bodies or spherosomes
      b. Half membrane: polar, hydrophobic surface exposed to 
          aqueous cytosol.  Nonpolar, hydrophobic surface 
          exposed to fats stored inside.
      c. Oleosomes originate from endoplasmic reticulum and 
  C. Formation of Fats
    1. Fats are not transported.  Synthesized in situ from 
         sucrose and other translocated sugars.
    2. Glycerol comes from glycolysis.  Fatty acids are formed 
         through acetyl-CoA and Malonyl-CoA.  Synthesized as 2-
         carbon units.  Hence the even number of carbons in 
         fatty acids.
    3. Environment:  determines the kinds of fatty acids found 
         in membranes and storage.
      a. Temperature
        (1) Low Temperature:  more linoleic and linolenic 
        (2) Unsaturation decreases average melting points.  
              Makes membrane more fluid in cold temperatures.
      b. Hypothesis: increased solubility of oxygen under 
           cold temperatures
        (1) Oxygen acts as the hydrogen atom acceptor for the 
              desaturation process in the endoplasmic reticulum
        (2) More oxygen at cool temperatures allows for more 
              unsaturation in the fatty acids
        (3) More unsaturation of fatty acids would allow 
              membranes to stay more fluid under cold 
              temperatures and protect them against freezing 
              damage (rupture due to ice crystal formation).
  D. Conversion of fat to sugars:  b-oxidation and the 
       Glyoxylate cycle
    1. Occurs in the glyoxysomes
      a. Lipases: enzymes used to remove the fatty acids from 
      b. b-oxidation: systematic removal of two carbon units 
           from the carboxyl end of the fatty acid.
    2.  One-fourth of the carbon atoms are lost from fatty 
         acids as CO2, the saving of 3/4 of the carbon atoms is 
         sufficient for the energy requirements of species with 
         fat-rich seeds during germination.

II. Waxes, Cutin, and Suberin: Plant Protective Coats
  A. Cuticle: slows water loss from all parts of the 
       herbaceous plant (leaves, stems, flowers, fruits, and 
    1. Protects from loss of water by transpiration
    2. Protection against plant pathogens
    3. Protection against minor mechanical damage
    4. Repellent for water used in agricultural sprays such as
         fungicides, herbicides, insecticides, or growth 
      a. Sprays are formulated with detergents (surfactants: 
           SURFace-ACTive-AgeNTS) that reduce the surface 
           tension of water and allow the spray to spread 
           across the foliage
    5. The cuticle is a heterogeneous mixture of components:
      a. Waxes
      b. Pectin polysaccharides attached to the cell wall
      c. Small amounts of phenolic compounds
    6. Cutins and waxes are synthesized by the epidermal cells
        and are then secreted onto the plant surface.  Waxes 
        can accumulate in various species specific patterns.
  B. Suberin:
    1. Suberin covers cork cells formed in tree bark by the 
         crushing action of secondary growth
    2. Suberin is formed by many kinds of cells as scar tissue 
         after wounding
    3. Suberin occurs in walls of non-injured root cells as a 
         Casparian Strip in endodermis and exodermis and in 
         bundle sheath cells of grasses.
    4. Suberin is the protective coating over underground plant 
    5. Phenolics bind to the lipid portion of suberin in the 
         cells wall.  Thus suberin is similar to cutin by
         having a lipid-polyester component, but differs by
         having an abundant phenolic fraction and by having 
         different kinds of fatty acids.

III. Isoprenoid Compounds
  A. General Background:
    1. All are composed of a five-carbon unit - isoprene (see 
    2. Called isoprenoids, terpenoids, or terpenes
      a. Terpene: isoprenoids that lack oxygen and are pure 
      b. Isoprenoids: Plant growth regulators (gibberellins 
           and Abscisic Acid), farnesol (stomatal regulator), 
           xanthoxin (precursor of Abscisic acid), sterols, 
           carotenoids, turpentine, rubber, and the phytol tail 
           of chlorophyll
    3. Thousands of isoprenoids have been found in the plant 
      a. Commercial uses are known for some
      b. For most isoprenoids, no function in the plant is 
           presently known
      c. Allelochemics:  compounds that influence another 
           species. Many isoprenoids function in this capacity.
      d. Alleleopathy: typically considered a special case of 
           alleleochemy in which there is a negative chemical 
           interaction between different plant species.
      c. Allelochemy against insects and other animal 
           herbivores is much more prevalent in plants than 
           is allelopathy
    4. Isoprene (C5H8): dimers, trimers, polymers of isoprene 
      a. Isoprene is synthesized from the acetate of 
      b. Mevalonic acid pathway
      c. Three acetyl-CoA molecules provide the five carbons 
           for one isoprene unit with the sixth carbon lost as 
  B. Sterols
    1. Sterols (steroid alcohols): triterpenoids built from 6 
         isoprene units
    2. Most common plant sterols:
      a. Sitosterol, Stigmasterol, Campesterol
      b. Cholesterol:  wide spread in trace amounts in plants
      c. Ergosterol:  rare in plants but common in some fungi.
           Ergosterol is converted by UV radiation of sunshine 
           to vitamin D2.
      d. Antheridiol:  sex attractant secreted by female 
           strains of the aquatic fungus Achlya bisexualis
    3. Sterols can exist as glycosides: a sugar (glucose or 
          manose) is attached to the hydroxyl group of the 
          sterol as an ester.  The hydroxyl group of the sterol 
          is attached to a fatty acid
      a. Free sterols exist in all membranes of all organisms 
           except bacteria.  Important in membrane stability.
      b. Sterol glycosides and esters do not exist in 
           membranes.  Currently their function is unknown.
      c. Some sterols have alleleochemical activity.
    4. Cardiac Glycosides: sterol derivative that cause heart 
          attacks in vertebrates
      a. Used in medicine to strengthen and slow the heartbeat 
           during heart failure.
      b. Coevolution of milkweeds, monarch butterflies, and 
           blue jays
        (1) Milkweeds produce bitter-tasting cardiac 
              glycosides that protect them against herbivory by 
              most insects and even cattle.  Monarch 
              butterflies have adapted.  Larvae ingest sterol 
              glycosides that later cause vomiting in Blue Jays 
              that eat the adult butterflies.  Other 
              butterflies have protective coloration that 
              makes them look like Monarch butterflies, thus 
              protecting them from the Blue Jays!
    5. Digilanides:  (Digitalis)  used since prehistoric times 
          as sources of arrow poisons.
      a. Toxins inhibit Na-K ATPases of heart muscle 
          membranes.  Heart failure occurs because of 
          hypertension or atherosclerosis
      b. Digitalis therapy gives a slower and stronger heart 
          beat.  Digitoxin, digoxin, or other derivatives used 
          for heart disease.
    6. Synthetic Animal Hormones:
      a. Female ovarian hormone progesterone
      b. Insect-molting hormones (ecdysones) exist in plants.  
          Insects rely on these and other plant sterols to form 
          hormones they need to mature.
      c. Triterpenoid saponins: sterols or sterol-like 
           compounds attached to short chains of sugars.  Have 
           various biological activities in animals.  Saponins 
           can cause foaming in the intestinal tract of cattle.  
           this can lead to serious bloat in cattle that eat 
           young alfalfa plants.
      d. Estrogens:  mammalian steroids including estrone, 
           estriol, estradiol.  It has been question whether 
           these and related steroids function within the 
           plant as sex or growth hormones.
      e. Brassins or Brassinosteroids:  these isoprenoid 
           derivatives have growth-promoting activity in some 
           plants.  Especially in stem elongation.  
           Brassinolide:  chemically similar to ecdysone.
  C. Carotenoids
    1. Yellow, orange, or red pigments in colored plastids - 
      a. Carotenes:  pure hydrocarbons
      b. Xanthophylls:  contain oxygen
      c. Both carotene and xanthophyll contain 40 carbon atoms 
           derived from eight isoprene units
    2. b-Carotene found in carrot roots
      a. b-carotene results from cultivation, useful to us 
           because our livers convert it to vitamin A.
           But, b-carotene in the roots of carrots does not 
           have a known function.
      b. b-carotene in mammals also protects against certain 
           cancers because it acts as an anti-oxidant.  Eat 
           your carrots!
    3. Lycopene: the red pigment found in tomato fruits.
    4. Lutein: a xanthophyll present in all plants especially
          in leaves.
    5. Carotenoids found in chloroplasts participate in 
        photosynthesis.  They are important in prevention of 
        photooxidation of chlorophyll.
    6. Carotenoids benefit some plants by attracting 
        pollinating insects.
    7. The Xanthophyll, Violaxanthin, is the metabolic 
        precursor of the plant hormone: Abscisic Acid.
  D. Miscellaneous Isoprenoids and Essential Oils
    1. Terpenoids:  10, 15, 20, or 30 carbons
      a. 10 or 15 carbons:  essential oils
        (1) Volatile compounds that contribute to odor.
        (2) 71 volatile compounds in orange peels mainly 
        (3) Widely used in perfumes.
        (4) Contributors to smog and other forms of air 
             pollution.  The Blue Ridge Mountains are blue 
             (especially in summer) are named because 
             of atmospheric scattering of blue light by tiny 
             particles derived from terpenes.
        (5) Essential oils attract insects to flowers 
             (aiding pollination) or to other plant parts on 
             which insects feed or lay eggs.
        (6) Turpentine: one of the best known essential oil
          (a) Genus: Pinus
          (b) Turpentine: n-heptane, a-pinene, b-pinene, 
          (c) Myrcene and limonene: represent important 
               terpenoids affecting tree-killing bark beetles.  
               These beetles are highly destructive in the 
               coniferous forests of North America, causing 
               millions of dollars of damage annually.
               It has been found in the Ponderosa pine that 
               limonene is an insect repellent, whereas a-
               pinene acts as an insect attractant or 
               aggregation hormone.  Trees with high limonene 
               and low a-pinene contents are rarely attacked by 
               pine beetles.
      b. Essential oils with hydroxyl groups or are 
          chemically modified in other ways:
        (1) Menthol and Menthone:  components of mint oils
        (2) 1:8 cineole:  eucalyptus oils.  Performs an 
             important function in pollination of orchids by 
             male euglossine bees.
      c. Glaucolide A:  complex terpenoid derivative.  Bitter 
          principles from family Asteraceae.  Bitter principles 
          repel chewing insects and mammals by their taste. 
          Glauscolide A from species in the genus Veronia 
          repel various lepidopterous insects, white-tailed 
          deer, and cottontail rabbits.
      d. Complex mixtures of terpenes containing 0- 30 carbon 
          atoms comprise the resins of coniferous trees, 
          and some angiosperms trees of the tropics.  These 
          terpenes are formed in the leaves by specialized 
          epithelial cells that line the resin ducts.  The 
          terpenes are secreted into the ducts where they 
          accumulate and protect the trees against insects.
  E. Rubber:
    1. 3,000 to 6,000 isoprenoid units
    2. Over 2.000 plant species form rubber in various amounts.
    3. Latex: from the tropical plant Hevea brasiliensis, a 
         member of the Euphorbiaceae family.
    4. Commercial rubber: comes from Castilla elastica.
    5. Even Dandelions produce latex!
    6. Guayule (Parthenium argentatum) common to Mexico and
        southwestern U.S. produces rubber.  Guayule was studied 
        during WWII and was selected in 1978 by U.S. Congress 
        for development as a natural rubber crop.
    7. If you visit Edison's Florida home you can still see 
        many plants that he imported from around the world that 
        produce rubber or latex.  He was studying them as 
        alternative rubber sources.

IV. Phenolic Compound and Their relatives
  A. General Information:
        The functions of most Phenolic compounds are still
        unknown.  May appear to be by-products of metabolism.
        This poor knowledge of ecological and the biochemistry 
        of plants is one reason that scientists want to study 
        the tropical rain forests before they are destroyed.  
        Can you imagine the important metabolic by-products 
        that may be out there and their possible uses!?  
        All phenolic compounds have an aromatic ring.  This 
        ring structure makes them more soluble in water and 
        less soluble in nonpolar organic solvents.
  B. Aromatic Amino Acids:
     1. Phenylalanine, tyrosine, tryptophan.
        a. Produced by way of the Shikimic Acid Pathway.
        b. The Shikimic Acid Pathway exists in plants, fungi 
            and bacteria but not in animals.
        c. The Shikimic Acid Pathway is inhibition by 
            Glyphosate (Roundup), a popular (but expensive) 
            herbicide.  Plants that absorb the herbicide are 
            injured or killed after one to two weeks, because 
            they cannot synthesize phenylalanine, tyrosine, and 
            tryptophane.  Since animals do not have the
            Shikimic Acid Pathway this herbicide is non-toxic!
  C. Miscellaneous simple Phenolics and Related Compounds:
     1. Cinnamic, p-coumaric, caffeic, ferulic:  derived 
         from phenylalanine.  They are converted into 
         several derivative besides protein.  These are 
         components of Phytoalexins, coumarins, lignin, and
         flavonoids such as anthocyanins.
     2. Protocatechuic Acid and Chlorogenic Acid: function
         in disease resistance of some plants.
        a. Protocatechuic acid prevents smudge in some colored 
            varieties of onions.
        b. Chlorogenic acid may also prevent diseases.  It is 
            widely distributed in different parts of many 
            plants.  Chlorgenic acid is found 13% by weight in 
            dry coffee.  It is not very toxic to humans.  
            Chlorgenic acid is formed in large amounts in 
            potato tubers.  Upon oxidation of chlorgenic acid 
            one finds the formation of quinones which are 
            responsible for the darkening of freshly cut 
            potato tubers.  Chlorogenic acid can also protect 
            plants against fungal attach since it is readily 
            metabolized to fungistatic quinones by disease-
            resistant plants.
     3. Ferrulic Acid:  also has a role in plant protection.
         Ferrulic Acid is forms part of the phenolic fraction 
         of suberin.
     4. Gallic Acid:  converted to gallotannins.  
        a. Gallotannins inhibit plant growth.  Gallotannins are 
             transferred to vacuoles, where they are unable to 
             denature cytoplasmic enzymes.
        b. Gallotannins are used commercially to tan leather.  
             Tannins denature proteins by cross-linking them.  
             This cross-linking also prevents their digestion 
             by bacteria, thus acting as a preservative.  
        c. Another function of tannins is to protect plants 
             against attack by bacteria and fungi, and as a 
             feeding deterrent against herbivores.  The 
             astringency of tannins inhibits both the digestion 
             and utilization of foods by herbivores.
     5. Coumarins:  scopoletin and coumarin:
        a. Formed in the shikimic acid pathway from 
            phenylalanine and cinnamic acid.
        b. Coumarin is a volatile compound that is formed 
            mainly from nonvolatile glucose derivative upon 
            plant senescence or injury.  Alfalfa and sweet 
            clover, characteristic odor of recently mowed hay.
        c. Economic importance:  
           (1) Dicumarol:  anticoagulant responsible for sweet-
               clover disease a hemorrhagic or bleeding disease 
               in ruminant animals that are fed plants that 
               contain it.
           (2) Seed-clover strains have been developed that 
               contain small amount of coumarin.
        d. Scopoletin:  a toxic coumarin.  Often found in seed 
            coats.  Suspected of preventing germination of 
            certain seeds and inducing seed dormancy.  
            Scopoletin is usually leached out of seeds by rain, 
            thus allowing the seed to only germinate when 
            abundant moisture is present and not before.
     6. Preocenes:  cause premature metamorphosis in several 
          insect species by decreasing the level of insect 
          juvenile hormone.  Sterile adults feeding on plants 
          high in preocenes have reduced pheromone production.  
          This is very promising as an insecticide.

V. Phytoalexins, Elicitors, and Plant Disease Protection
  A. Phytoalexins: antimicrobial compounds that are more toxic 
      to fungi than to bacteria
     1. Glyceollins:  soybean roots
     2. Pisatin:  pea pods
     3. Phaseollin:  bean pods
     4. Ipomeamarone:  sweet potato roots
     5. Orchinol:  orchid tubers
     6. Trifolirhizin:  red clover roots.
  B. 150 Phytoalexins have been identified, especially in 
      dicots.  Phytoalexins are phenolic phenyl propanoids 
      which are products of the shikimic acid pathway.  Some 
      are isoprenoid compounds and a few are polyacetylenes.
  C. Pathogenic fungi that are successful in attaching plants 
      do so because they either induce only nontoxic 
      phytoalexin levels or quickly degrade the phytoalexins 
      produced by the plant.
  D. Viruses and different kinds of compounds can induce 
      phytoalexin production in plants.  Compounds that cause 
      phytoalexin production are called elicitors.  Some 
      elicitors are polysaccharides that are produced when 
      pathogenic fungi or bacteria attack plant cell walls.  
      Other elicitors are the polysaccharides produced from 
      the degradation of fungal cell walls by plant enzymes 
      whose production was stimulated by the fungal pathogens.
  E. Physical injury and ultraviolet radiation can induce 
      phytoalexin production by plants.  
  F. Exogenous elicitors are recognized by receptor proteins in 
      plant membranes.  These receptor proteins signal the 
      plant to produce phytoalexins.

VI. Lignin:
  A. Lignin is a structural material that occurs with 
      cellulose and other polysaccharides in certain cell walls 
      of all higher plants.  It adds strength to the cell 
      walls, especially secondary cell walls.
  B. Largest amounts of lignin can be found in wood where it 
      accumulates to a minor extent in the middle lamella, and 
      primary walls, and to a large extent in the secondary 
      walls of the xylem elements.  Lignin is found between the 
      cellulose microfibrils, serves to resist compression 
  C. Resistance to tension (stretching) is primarily a 
      function of cellulose.
     1. Lignin formation was crucial in the adaptation of 
         plants to a terrestrial environment.
     2. Rigid xylem cell walls are built to conduct sap under 
         tension over long distances.  Lignin is the second 
         most abundant organic compound on earth next to 
         cellulose.  It makes up 15 to 25 % of dry weight of 
         woody plants.
  D. Lignin protects against attack by pathogens and 
       consumption by herbivores, other insect and mammals.

VII. Flavonoids:
  A. Flavonoids are 15-carbon compounds distributed throughout 
      the plant kingdom.  Flavonoids accumulate in the central 
      vacuole, but are synthesized outside the vacuole.
  B. Anthocyanins, Flavonols, Flavones
    1. Anthocyanins:  colored pigments that occur in red, 
        purple, and blue of flowers, fruits, stems, leaves, and 
        roots.  Confined to epidermal cells.  Autumn leaf color 
        is caused by anthocyanin accumulation on bright, cool 
        days, although yellow or orange carotenoids are the 
        predominant pigments in autumn leaves of some species.  
        Rarely found in gymnosperms.
    2. Anthocyanidins:  removal of the sugar, and are usually 
        named after the plant from which they were first 
       a. Cyanidin: blue cornflower Centaurea cyanus
       b. Pelagonidin: bright red geranium Perlargonium
       c. Delphinidin: Delphinium blue larkspur
       d. Peonidin: reddish peonies
       e. Petunidin: purple in petunias
       f. Malvidin: mauve, Malvaceae
    3. Color of anthocyanins depends on:
       a. substituted groups present on the B ring.
          (1) Methyl groups cause a reddening effect.
       b. association of anthocyanins with flavones, or 
          flavonols, which cause them to become more blue.
       c. association with each other
          (1) at high concentrations, can cause either a 
               reddening or a bluing effect
          (2) depends on the anthocyanin and the pH of the 
               vacuoles in which they accumulate.  Reddish in 
               acidic solution, purple and blue in basic pH.  
          (3) Epidermal cells containing delphinidin increases 
               from a pH of 5.5 to 6.6 during aging.  Reddish 
               purple to purplish.  Wide variation the hues of 
    4. Functions in flowers as an attractant for birds and bees 
        that carry pollen from one plant to another, aiding in
    5. Anthocyanins may play a role in disease resistance.
    5. Anthocyanins and flavonoids are of interest to plant
         geneticists because it is possible to draw 
         correlations between morphological differences of 
         closely related species in a particular genus with the 
         types of flavonoids they contain.
  C. Flavones and flavonols are yellowish or ivory-colored 
       pigments.  Flavones and flavonols absorb ultraviolet 
       wavelengths.  The ultraviolet radiation is visible to 
       bees and other insects involved in pollination.  
       Absorption of  UV radiation, also acts as a protection 
       against long-wave UV rays.  Flavones and flavonols are 
       widely distributed in leaves where they act as feeding 
    1. Light (especially blue wavelengths) promotes formation 
        of flavonoids.  Reddest apples are found on the sunny 
        side of the tree.
    2. Nutritional status of a plant affects production of 
        anthocyanins.  Deficiencies of nitrogen, phosphorous, 
        or sulfur leads to accumulations of anthocyanins
    3. Low temperatures increase anthocyanin formation.
  D. Isoflavonoids: functions of are mostly unknown, but they 
      may have possible Alleleochemic abilities.
    1. Rotenone: isoflavonoid from the root of derris (Derris 
        elliptica).  This is an insecticide that resembles 
        animal estrogens.
    2. Estradiol, certain plant Isoflavonoids cause 
        infertility in female livestock, especially sheep.
    3. Subterranean clover has high levels of isoflavones.  
        Clover disease of sheep in the 1960's in western 
        Australia caused a decline in fertility.  Isoflavones 
        were suspected to be a factor controlling rodent 
        populations in certain regions.  Their infertility 
        effects do not seem to deter grazing animals.

VIII. Betalains
  A. Red pigment of beets is a betacyanin
  B. Red and yellow betalain pigments thought to be related to 
         the anthocyanins
    1 Contain nitrogen
    2 Yellow betaxanthins
  C. Restricted to 10 plant families: Caryophyllales which lack 
  D.  Colors: flowers, fruits, yellow orange re and violet
    1 Vegetative organs 
    2 Synthesis is promoted by light
    3 Betanin:  red beet roots
  E. Role in pollination comparable to that of anthocyanins in 
      other species seems likely.  
  F. Protection against pathogens is another possible function

IX. Alkaloids
  A. Aromatic nitrogenous compound.  Many are slightly basic.  
       Most are white crystalline compounds slightly water-
  B. Dramatic physiological or psychological activity in 
  C. More than 3,000 alkaloids have been found in some 4,000 
       species of plants
    1. herbaceous dicots
    2. few monocots and gymnosperms possess alkaloids
  D. Examples:
      Morphine:  1805 opium poppy Papaver somniferum
      Nicotine:  tobacco
      Cocaine:  Erythroxylon coca
      Quinine:  cuprea bark
      Caffeine:  coffee beans and tea leaves
      Strychnine:  seeds of Strychnos nuxvomica
      Theobromine:  cocoa beans
      Atropine:  black nightshade (Atropa beleadonna)
      Colchicine:  Colchicum byzantinum
      Mescaline:  hallucinogenic and euphoric drug from 
        flowering heads of cactus Lophophora williamsii 
      Lycoctonin:  Delphinium barbeyi
  E. Most alkaloids are synthesized only in plant shoots.  
       Nicotine is produced only in the roots of tobacco.
  F. Physiological roles of alkaloids in plants is unknown.
    1 No important metabolic function found.
    2 Merely by -products?
    3 Confer some protection to plants.
    4 Avoided by grazing animals and leaf-feeding insects.
    5 Danaid butterflies as substrates for synthesis of their 
         courtship pheromones.
    6 Larkspur is not avoided by cattle.  But lycoctonine in 
       Larkspur accounts for more cattle deaths in the U.S. 
       than any toxin in any other poisonous plant.