Euphorbiaceae

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Euphorbiaceae

• Distribution predominantly tropical, although
  there are strong local concentrations in extra
  tropical regions such as USA, Middle East and
  South Africa, eg Euphorbia
• greatest number of genera are entirely tropical
• richest concentration of family is in the
  Indomalaysian region, with New World Tropics
  coming in second

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Diagnostic Features

• Habit herbs, shrubs, trees
• Lvs. alt. or rarely opp., stipulate, simple but
  when compound, always palmate and never pinnate
• Infl. - cyathium
• Flws. regular, unisexual, monoecious
  (Euphorbia), or dioecious (Mercurialis)
• Perianth usually five tepals but some species
  petals are also present eg Jatropha, absent in
  some species

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Jatropha multifida
Ricinus communis
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Jatropha
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• Androecium numerous stamens
• Gynoecium pistillode is often present in
  staminate flowers, ovary superior with three
  fused carpels and three locules, styles free or
  united
• Fruit schizocarp or sometimes a drupe, or a
  type of schizocarp called regma where the
  mericarps themselves dehisce after having
  separated from each other

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Regma
Drupe
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• latex is present in the tribe Euphorbieae but is
  generally absent from other tribes usually
  poisonous, especially in Hipomane mancinella, the
  mancineel tree of the West Indies and can cause
  temporary blindness

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• glands are a noteworthy feature of many
  Euphorbiaceae generally associated with flws.
  (stamens, ovary or infl.) or with vegetative
  organs
• pseudanthium present in the tribe Euphorbieae

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• cyathium specialized infl. of the Euphorbiaceae
  which is a small cup-shaped structure consisting
  of a turbinate involucre which bears a number of
  glands of varying shape around its rim within
  the involucre are numerous staminate flws., each
  of very simple structure surrounding a single
  central pistillate flower
• inlf. commonly protogynous, cross pollination by
  flies of Order Diptera which are attracted to the
  cyathia by the flat gland platforms that produce
  copious nectar

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Classification

• Division Magnoliophyta
• Class Magnoliopsida
• Subclass Rosidae
• Order Euphorbiales
• Family Euphorbiaceae

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Classification

• divided into 8 major tribes
• consists of 300 species and over 5000 genera
• Euphorbia, the type genus is not a typical member
  due to extreme simplicity of flws.
• largest genera are Phyllanthus, Euphorbia,
  Croton, Acalypha

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Economic Importance

• Hevea brasiliensis, the para rubber tree is the
  source of most of the worlds natural rubber
• Manihot also includes rubber producing species
  such as M. glaziovii and cassava or tapioca
  plant, Manihot esculenta
• Ricinus communis yields castor oil
• Sapium sabiferum (Chinese Tallow Tree) yields
  grease surrounding seeds which is used in making
  soap and candles leaves yield a black dye

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Hevea brasilensis
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Manihot esculenta
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Aceraceae

• family of predominantly medium to small,
  deciduous trees of northern temperate regions
• includes some large trees and evergreens, and a
  few subtropical species
• has only two genera, Acer, the maples, and
  Dipteronia

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Distribution

• the two Dipteronia species are found in central
  and southern China
• maples have an enormous geographic range centered
  in China, where 100-150 species are found
• in North America there are four maples native to
  western states only, eight native to the eastern
  and southern states, while one, A. negundo, is
  found from Montreal to southern California

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Diagnostic Features

• branches grow in opposite pairs
• lvs. are opposite and highly variable in shape
  simple or compound, entire or deeply toothed,
  unlobed or deeply lobed, exstipulate
• Flws. regular, andromonoecious (staminate and
  bisexual flws. on same plant), androdioecious
  (staminate and bisexual on different plants), or
  dioecious
• Perianth 5 free sepals and 5 free petals
  (sometimes absent)

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• Androecium staminate and bsexual flws. have
  4-10 stamens, normally eight
• Gynoecium vestigial ovary often present in
  staminate flws., ovary superior, two fused
  carpels, two locules
• Fruit samaroid schizocarps, each mericarp with
  a wing

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Classification

• Division Magnoliophyta
• Class Magnoliopsida
• Subclass Rosidae
• Order Sapindales
• Family Aceraceae

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Classification

• comprises of two genera and 102-152 species
• Acer differs from Dipteronia in having obovate
  wings attached to the seeds Dipteronia seeds are
  surrounded by a circular membrane
• Aceraceae is related to the Sapindaceae and
  Hippocastanaceae

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Economic Importance

• many maples are grown for ornamental purposes,
  and prized for their beautiful foliage and
  spectacular autumn colors
• many species produce good timber (Acer
  pseudoplatanus), while the sugar maple (Acer
  saccharum) yields maple sugar