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Orchids: Where is my home? - Smithsonian · PDF fileOrchids: Where is my home? Activity:...

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  • 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.

    Orchids: Where is my home?

    www.gardens.si.edu

  • 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 childrens knowledge and understanding of orchid homes, promotes discussion, and stimulates creativity.

    What youll 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.

    Vocabulary

    Terrestrials

    Epiphytes

    Lithophytes

    Pseudobulbs

    Orchids: Where is my home?

    www.gardens.si.edu

  • 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.

    Dont 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

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