Orchids: Where is my home?

Orchids: Where is my home?
Introduction
Orchids can grow in a variety of habitats such as marshes and wetlands, on trees, in the ground,
on cliffs, riverbanks and areas where decaying organic matter and the fungi that grow there provide food
for orchids. Orchids can be divided into three main groups based on their habitat: terrestrials, epiphytes,
and a subset of epiphytes called lithophytes. Orchids can also interchange their habitat depending on the
circumstances in which they find themselves. For example, an epiphytic seed can land and grow in a well
drained but still moist area, like a rock next to a stream, if there is enough moisture to sustain its growth.
Terrestrial orchids
These orchids have the ability to adapt to growing conditions that are quite varied: from boggy
ravines to damp forest floors, from sandy dunes to semi-arid desert soil. The roots of terrestrial orchids
sometimes produce tubers that lie just below the soil surface or even deep underground depending on
the circumstances. Sometimes roots are sent directly into substrate such as soil. Temperate terrestrial
orchids are often deciduous in that their flowers and leaves fade in winter and remain underground until
the new growth season begins. New growth will then appear as a single leafy stem topped by flowers.
Examples of terrestrial orchids include Cymbidium, Ladyslipper and Jewel orchids.
Epiphytic orchids
Epiphytic orchids grow on host trees. They are usually supported by the trunk or the thick lower
branches of the host, though sometimes they perch on small twigs in the very top of the tree canopy. All
epiphytes cling to their hosts with very strongly developed root systems. These roots take advantage of
the moisture and organic debris that are caught in the crevices and bark of the host for nourishment
purposes. All additional moisture and nutrients that are required are absorbed from the humid tropical
air, rain, and mosses, ferns and fungal symbionts.
Epiphytic orchids benefit from the microclimates offered by their hosts. Some epiphytic orchids
evolved in shade or moderate dappled light and therefore favor growing on the trunk or lower branches
of the host tree; others that require direct sunlight and ventilation will be found higher in the canopy at
the top of the host tree. Some of the most notable and familiar types of orchids that are epiphytic are in
the genera Dendrobium, Cattleya and Phalaenopsis.
Lithophytic orchids
Lithophytic orchids are mainly found in the tropical regions of the world. They grow on exposed
rocks. They have strong roots that burrow into small crevices and absorb moisture and nutrients found
amongst the moss and organic debris that collect in them. Some orchids such as the Hoffmannseggellas
(Rupicolous Cattleyas of Brazil) grow amongst pebbles.
The leaves of lithophytic orchids are often quite fleshy; they and the pseudobulbs (a part of the
plant specifically modified for the storage of energy and derived from the part of the stem between two
leaf nodes) carry the plant through any prolonged dry spells that might occur. Examples of lithophytic
orchids include Dendrobium kingianum, Dendrobium speciosum, Bifrenaria and Maxillarias.
www.gardens.si.edu
Orchids: Where is my home?
Vocabulary
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Terrestrials
•
Epiphytes
•
Lithophytes
•
Pseudobulbs
Age/Grade level: Elementary school students
Learning Goals:
Have students understand that orchids can be
divided into three main groups according to
where they live, namely terrestrials (which
grow in the ground), epiphytes (which live upon
trees), and lithophytes (which live on rocky
cliffs).
To foster a fun learning activity that expands
children’s knowledge and understanding of
orchid homes, promotes discussion, and
stimulates creativity.
What you’ll need:
Picture of terrestrial Orchid
Picture of epiphyte Orchid
Picture of lithophyte Orchid
Terrestrial label
Epiphyte label
Lithophyte label
“Create Your Own Orchid” Activity Sheet
Rock*
Small Tree Branch*
Soil*
Scissors*
Crayons, markers, or colored pencils*
*Starred items are not included in the activity packet
Preparation:
Use scissors to cut out the terrestrial, epiphyte,
and lithophyte orchid images and labels along
the dotted lines for the matching activity.
Gather soil, a rock, a small tree branch, markers,
crayons, or colored pencils as they are not
included in the activity packet.
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Orchids: Where is my home?
Activity:
Discuss
Just like people have homes, orchids have homes. Ask children if they know where orchids live.
Share that orchids live on the ground (terrestrials), on trees (epiphytes), and on rocks (lithophytes).
A habitat is a place where an organism or a community of organisms lives. It includes all living and
nonliving elements or conditions of the surrounding environment. Orchids grow all over the world in
many cultural conditions. While soil, rocks, and trees often are found together, and therefore are part
of the same habitat, the adaptability and biodiversity of orchids often depends on the ‘substrate’ or
surface on which it grows.
o Think of a habitat and discuss which type(s) of orchid would like to grow there: epiphyte,
lithophyte or terrestrial?
o Why would the orchid favor this habitat?
o Describe the habitat (home, neighborhood, city) that you currently live in.
o What makes it a comfortable habitat for you?
o What type of habitat would you like to live in?
Play
Play a fun matching game by using the images of an epiphyte, lithophyte, and terrestrial, the labels,
and the rock, soil, and tree bark.
Create
Encourage creativity and topic reflection by using the “Create Your Own Orchid” activity sheet.
www.gardens.si.edu
This epiphyte is a Telipogon species in a cloud forest near
Macas, Ecuador.
This terrestrial orchid is a Cypripedium parviflorum growing in the
G. Richard Thompson Wildlife Management Area in Virginia.
This lithophyte is a Maxillaria and is growing in the mountains outside of
Banos, Ecuador.
epiphyte
lithophyte
terrestrial
CREATE YOUR OWN ORCHID
In the box below create your own orchid and come up with a name for it.
Don’t forget to draw its home!
Is it a terrestrial, an epiphyte, or a lithophyte?
My orchid is called _______________________________________________________
Its home is (circle one)
in the soil
a tree
a rock
Which means it is a (circle one)
terrestrial
epiphyte
lithophyte