Genus of the Week
Week of Feb. 8-14
This page has been created for people who want to learn more about plants, especially in the
context of their taxonomy (Latin names, etc.). This is by no means an exhaustive list of
all available Web resources for a particular genus.
If you like this page, you should also visit the Land of the Glandular Trichomes
, a microscopic look at plants in the Lamiaceae family.
This week's genus:
Hydrangea
Subclass: Dicotyledoneae
Superorder: Rosidae
Order: Rosales
Family: Saxifragaceae
Number of Species: at least 4
Root: Named by Linnaeus for "hydrange", meaning a water vessel. This may be in
reference to the cup-shaped seed capsule, or the fact that Hydrangea prefer wetland
habitats.
The genus Hydrangea is best known for its widely cultivated garden species.
Horticulturists prize these species for their large brightly colored inflorescences.
For centuries herbalists have been using the rhizome and root of Hydrangea to ease the
pain of dispelling kidney stones. What I find to be most interesting about species in this
genus is the pH sensitivity of their flower pigments (anthocyanins). If grown in alkaline
soils, the flowers are pink or purplish, while those plants grown in acidic soils produce blue
flowers.
Here are some links to images and information concerning the genus Hydrangea:
- Follow a set of five web pages put together by a college senior at Purdue University and
see photos of Oakleaf
Hydrangea, including close-ups of the unique foliage.
- Check out the Plant Encyclopedia, part of the Gardener's Library at HomeArts.com, for
information and a picture about
H. anomala petiolaris (Climbing Hydrangea), a woody vine native to Asia. This site
also has information about
H. paniculata grandiflora (Peegee Hydrangea) and
H. macrophylla (Blue-flowered Hydrangea).
-
Here is information about anthocyanins plus some neat experiments to perform to measure pH
using flower petals, brought to you by The Woodrow Wilson Leadership Program in Chemistry.
References:
- Grieve, M. (C. F. Leyel, ed.). A Modern Herbal. London, Tiger Books International: 1973.
- Heywood, V.H., ed. Flowering Plants of the World. New York, Oxford University Press: 1993.
- Raven, Peter H., Evert, Ray F. and Eichhorn, Susan E. Biology of Plants, fifth edition. New York, Worth Publishers: 1992.
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