Download Range Site Evaluation

Characteristics of Stems
AGR 161: Unit C
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Edited By: Jennifer Stewart
Objectives


Identify stem characteristics important
for plant identification
Recognize stem adaptations that
provide protection for plants
Stems

Two main functions
 movement of water and minerals
from the roots upward
 movement of manufactured food
down
Stems Also…



support of leaves and reproductive
structures
used for food storage and
reproduction of plants involving
cuttings
Green stems manufacture food just
as leaves do
External Stem Structure


lenticels- breathing pores
bud scale scars-indicate where
terminal bud has been located
previous year.
Leaf Scars


Shows where leaf was attached
Distance between the two
represents one year of growth.
What are the types of stems?
1) Woody Stem: trees, shrubs,
woody perennials
2) Grass Stem: hollow or filled
3) Herbaceous Stem: like woody but
softer (clover, alfalfa)
4) Modified Stem:
Specialized Stems

A. Corm (gladiolus,
crocus)


underground
Solid, fleshy, scale
covered
Specialized Stems

B. Bulb (tulips,
lillies, onions)


Layers of fleshy
scales that overlap
each other
Underground stem
Specialized Stems

C. Tuber (potato,
caladium)


Food storage area
Short, thick
underground stem
Specialized Stems

D. Crown (African
Violets, fern)


Closely grouped
stems or plantlets
Just above ground or
just below
Specialized Stems

E. Spurs (pear and
apple trees)

Short sems found on
woody plant limbs
adapted for
increased production
of fruits
Specialized Stems

F. Rhizomes (iris,
lily of the valley)

Underground stems
that produce roots
on the lower surface
and extend leaves
and flower shoots
above the ground
Specialized Stems

G. Stolon
(Strawberry, airplane
plant)

Stem that grows
horizontally above
the soil surface
Review




What are the four types of stems?
What are some example of specialty
stems?
What function does the stem serve?
How can stems adapt to provide
protection for the plants?