Taxonomy
of Flowering Plants - LECTURE
NOTES - Fall, 1998
Hugh
D. Wilson - rm. 306,
Butler Hall
The Asteridae
Family Overview - Lamiales
Lamiaceae (Labiatae) - the Mint Family
Diversity: Herbs and shrubs
that, like the Apiaceae,
shows a center of diversity in the Mediterranean basin and a tendency to
produce volatile oils. Thus, of the ca. 200 genera and 3, 200 species,
many are used as herbs and spices for cooking. These include sage
(Salvia officinalis), rosemary (Rosmarinus officinalis)),
mint (several Mentha species), and many others.
Distribution: Worldwide,
with greatest diversity in north temperate ares, especially southern Europe
and the Mediterranean. We have 31 genera and 126 species in the Texas
flora, including 10 endemic
species and the endemic genus, Rhododon.
Floral structure:
Significant features: This
family carries the distinctive gynoecium of the Lamiales
in that the ovary usually shows a second septum, producing 4 locules
and each of these has only a single seed. Most mints show a 4-lobed
gynoecium and gynobasic style, similar to that of the Boraginaceae. Contrasting
with the Boraginaceae, the Lamiaceae usually show a quadrangular stem and
opposite leaves. While sharing corolla zygomorphy with the Verbenaceae,
this is usually more pronounced to produce a bilabiate or 'two-lipped'
corolla. Pubescence of most taxa of the Lamiaceae includes glandular
trichomes that secrete volitale oils producing the 'minty' smell
or taste that is a good key character. As indicated below, the Lamiaceae
also tend to have the flowers positioned as whorls at the nodes.
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Salvia officinalis
- common sage of Europe - overview from Kohler's
Medicinal Plants (note gynoecium, androecium detail) and photo
of inflorescence (right) |
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common in local woodlands,
native: Salvia lyrata
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plant
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flowers
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bee-eye view
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mature gynoecium
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Monarda citriodora
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floral whorls/bracts
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flowers - side
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flowers - bee-eye view
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calyx/corolla
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Distinctive
genera: Scutellaria - skullcap
- (left) calyx with inflated 'cap', and Teucrium - germander
- no upper lip for the corolla (right) = 'unilabiate' corolla |
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More information on the Lamiaceae
(or Labiatae)
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201 homepage, or the Asteridae
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