Page 164 - Ultimate Visual Dictionary (DK)

PLANTS

Epiphytic and parasitic plants

EPIPHYTIC AND PARASITIC PLANTS GROW ON OTHER LIVING PLANTS. Typically, epiphytic plants are
not rooted in the soil; instead, they live above ground level on the stems and branches of other
plants. Epiphytes obtain water from trapped rainwater and from moisture in the air, and
minerals from organic matter that has accumulated on the surface of the plant on which
they are growing. Like other green plants, epiphytes produce their food by photosynthesis. Epiphytes
include tropical orchids and bromeliads (air plants), and some mosses that live in temperate regions.
Parasitic plants obtain all their nutrient requirements from the host plants on which they grow. The parasites
produce haustoria, rootlike organs that penetrate the stem or roots of the host and grow inward to merge
with the host’s vascular tissue, from which the parasite extracts water, minerals, and manufactured nutrients.
As they have no need to produce their own food, parasitic plants
lack chlorophyll, the green photosynthetic pigment, and they
have no foliage leaves. Partial parasitic plants (e.g., mistletoe)
Inflorescence
obtain water and minerals from the host plant but have (spike) Peduncle
green leaves and stems and are therefore able to (inflorescence
produce their own food by photosynthesis. Flower stalk)
bud
EPIPHYTIC ORCHID
Strap-shaped
Brassavola nodosa
arching leaf
(part of rosette
Peduncle of leaves)
(inflorescence Leaf margin
stalk) with spines
Flower
Pedicel Overlapping leaf
(flower bases in which
stalk) rainwater is trapped Mass of
adventitious roots
EPIPHYTIC BROMELIAD Stem
Aechmea miniata
Bark of tree to
Scale which epiphyte
leaf Leaf is attached

Velamen Exodermis
(multi-layered epidermis (outer layer
capable of absorbing of cortex)
water from rain or
condensation)

Cortex
(layer between
epidermis and
vascular tissue)
Aerial
root Cortex cell
Node containing
chloroplasts
Pith
Stem
Vascular Xylem
tissue Endodermis
Phloem (inner layer
of cortex)
Bark of tree to
which epiphyte MICROGRAPH OF CROSS-SECTION THROUGH
is attached AERIAL ROOT OF EPIPHYTIC ORCHID
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