Agriculture Reference
In-Depth Information
Introduction
Flowers form an integral part of human life, they are presented at birthdays, wed-
dings, graduations, funerals and other special occasions. Ornamental plants are
grown for their beauty and function in gardens, parks, and homes of people. Produc-
tion is in nurseries as bedding plants, pot plants, foliage or as cut flowers. Flowers
are produced worldwide on a large scale for commercial purposes by growers and
distributed to wholesale, markets and flower shops to be sold to the consumer. A
second use of ornamental plants is their uses in gardening and landscaping. Orna-
mental plants are used by humans because of their beauty, symbolic significance
(Mendonca de Carvalho
2011
; Koehn
1952
; Ferguson
1966
), colour (Kaufman and
Lohr
2008
), fragrance, therapeutic (Matsuo et al.
2008
) and emotional value.
In this chapter the role of ornamental plants in human life is summarized and
focuses on cultural, environmental, horticultural and genetical aspects.
Cultural Aspects
Flowering plants (angiosperms) produce colourful, showy flowers as a mean of at-
tracting insect, bird, bat or animal pollinators to produce seed for the continuation of
the species. In contrast, wind pollinated plants, particularly conifers (gymnosperms),
grasses, sedges and other woody shrubs/trees have less showy flowers. While foli-
age, plant shapes, and fruit frequently have ornamental qualities, flowers have al-
ways captured the attention of human eyes. As a result, flowers have been highly
integrated into human cultures and societies throughout the world in all ages being
used for art, adornment, decoration, fragrance, medicine, food and floral design.
Flowers come in a wide variety of sizes—from the microscopic duckweed
(
Wolffia columbiana
) to the gigantic aroids (
Amormorphallus paeoniifolius
);
shapes—star or actinomorphic, yolk or zygomorphic, actinomorphic flowers pro-
duced in a plant that normally is zygomorphic—also known as peloric types; co-
lours—all are possible across the spectrum of plants, although some species and
genera have only a few colours; black, blues and greens are rare in most species. In
floral designing, the design elements (line, form, texture, colour and fragrance) are
all provided by flowers and their stems used in each design (Hunter
2000
). All flow-
ers can be categorized into distinctive forms for floral designing: mass, line, form,
and filler (Hunter
2000
). Mass flowers have one or more flowers or florets clusters
in a single spot at the tip of each stem, providing a mass appearance, such as:- dahlia
(
Dahlia pinnata
), chrysanthemum (
Chrysanthemum x grandiflorum
), or rose (
Rosa
x hybrida
). In floral designing, mass flowers are typically used for the focal point
or centre of interest. Line flowers are stems with multiple flowers or florets occur-
ring up and down each stem, e.g. gay feather (
Liatris spicata
), gladiolus (
Gladiolus
x hybridus
), or snapdragon (
Antirrhinum majus
). In floral designing, line flowers
help create geometric forms and provide a line of similarity for the viewer's eye to
follow. Form flowers are unusually shaped and call attention to themselves due to
