Stem

FUNCTIONS
  1.

Conduction
of
food
and
water
  2.

Formation
and
support
of
leaves
and
buds

  3.

Storage
of
food
ORIG...
EXTERNAL
STRUCTURE
OF
STEMS
  Nodes
  Internodes
  Leaves
  Buds
  Leaf
scar

  Vascular
bundle
scar

  Bud
scales
...
Primary
growth
of
the
plant
body

ProtodermGround meristemProcambium
PRIMARY
PERMANENT
TISSUES

PRIMARY
PERMANENT
TISSUES
  1.

Epidermis

  2.

Cortex
  3.


Vascular
tissues
  4.

Pith

  5.


Endodermis
  6.

...
  
3.
Vascular
tissues
    A.

Primary
xylem
     Protoxylem
–

       First
part
of
the
10
xylem
to
mature
       Ma...
Primary
xylem
development
  EXARCH
–
First
xylem
elements
to
mature
are
     farthest
from
the
center
of
the
axis;
     m...
Primary
xylem
development
Left
to
right‐



A.

Lycopodium
flabelliforme
rhizome;
B.

Osmunda
;

























...
B.
PRIMARY
PHLOEM
  PROTOPHLOEM‐
With
sieve
elements,
may
  have
no
companion
cells;
function
for
a
short
  period
of
tim...
Primary
phloem
in
Zea
mays

Vascular
bundle
of
Ranunculus

Ricinus
hypocotyl

Vascular
bundle
in
Cucurbita
maxima

VASCULAR
BUNDLES‐
Strands
of
conducting
  tissue
TYPES:
  A.

COLLATERAL
BUNDLE‐
A
bundle
with
   phloem
on
one
side
of
x...
VASCULAR
BUNDLES
TYPES:
  C.

CONCENTRIC
BUNDLES
–
A
bundle
where
   one
vascular
tissue
surrounds
the
other
    1.
AMPH...
Types
of
bundle

Types
of
bundle

PRIMARY
PERMANENT
TISSUES
  1.

Epidermis

  2.

Cortex
  3.


Vascular
tissues
  4.

Pith

  5.


Endodermis
  6.

...
  4.

PITH
  5.

ENDODERMIS‐
the
innermost
layer
of
the
  cortex
  6.
PERICYCLE‐
the
fundamental
tissue
of
the
  stele;...
Starch
sheath
in
Ricinus

Perivascular
fibers
in
Cucurbita

TYPES

OF
STELE
  PROTOSTELE‐
Solid
column
of
vascular
tissue
  without
pith

    A.
HAPLOSTELE
–solid
core
of
xylem
   ...
  TYPES

OF
STELE
  SIPHONOSTELE‐
vascular
tissue
surrounds
a
  non‐vascular
core,
the
pith
    A.

ECTOPHLOIC
SIPHONOS...
  EUSTELE‐
a
stele
with
interfascicular
     parenchyma
and
collateral
or
bicollateral
     bundles
  ATACTOSTELE‐
a
ste...
NODES
AND
INTERNODES
(ANATOMY)
  1.
Differ
in
arrangement
of
vascular
tissues
    A.

LEAF
TRACE‐
a
vascular
bundle
loca...
Leaf
trace
and
gap

NODES
AND
INTERNODES
(ANATOMY)
  TYPES
OF
NODE
    1.
ONE‐TRACE
UNILACULAR‐
with
a
single
   gap
and
a
single
trace
to
a...
Types
of
node

Types
of
node

NODES
AND
INTERNODES
(ANATOMY)
  1.
Differ
in
arrangement
of
vascular
tissues
    C.
BRANCH
TRACES‐
vascular
supply
of
t...
NODES
AND
INTERNODES
(ANATOMY)
  2.
The
cortical
and
pith
cells
may
be
shorter
in
  the
nodes
and
there
may
be
less
scler...
Cucurbita
stem

PRIMARY
GROWTH
OF
THE
AXIS
  INCREASE
IN
HEIGHT
    primarily
through
growth
of
internodes
by:
  INCREASE
IN
DIAMETER
 ...
Primary
thickening
meristem

Secondary
growth
of
the
plant
body

VASCULAR
CAMBIUM

  forms
20
vascular
tissues
  
are
highly
vacuolated
  with
primary
pit
fields
  CELL
TYPES
    FUS...
  ARRANGEMENT
IN
TRANSECTION

   arranged
in
radial
series‐
cells
of
the
   cambial
zone
(initials
and
immediate
   deri...
  ARRANGEMENT
IN
TANGENTIAL
VIEWS
   1.
STORIED
OR
STRATIFIED
CAMBIUM
–
   fusiform
initials
in
horizontal
tiers
with
th...
Vascular
cambium
in
tangential
section

  CELL
DIVISION
    1.
MULTIPLICATIVE
DIVISIONS
–
radial
     (anticlinal)
divisions
that
increase
the
number
     of
in...
Multiplicative
divisions
in
fusiform
initials

  DEVELOPMENTAL
CHANGES
    New
rays
may
arise
from
fusiform
initials
or
   their
segments
    1.


from
the
apex
of
fu...
Origin
of
rays
from
fusiform
initials

Increase
in
width
of
ray

Increase
in
height
of
ray

Increase
in
height
of
ray

  SPLITTING
OF
RAYS
    1.

through
intrusive
growth
of
fusiform
initials
    from
a
group
of
ray
initials
    2.
throu...
Splitting
of
rays

  LOSS
OF
INITIAL

    2.
RAY
INITIALS
     A.
maturation
into
20
xylem
or

20
phloem
      elements

STORIED
AND
NONSTORIED
WOODS
  1)

NONSTORIED
CAMBIUM
‐
forms
nonstoried
wood
  2)

STORIED
CAMBIUM
–
forms
storied
or
n...
Vascular
cambium
in
tangential
section

Earlywood
and
latewood

Earlywood
and
latewood

SAPWOOD/HEARTWOOD
  SAPWOOD‐
functional
part
of
the
20
xylem
  HEARTWOOD
–
non‐functional
part
of
the
20
  xylem

SECONDARY
VASCULAR
TISSUES
  AXIAL
SYSTEM
–originates
from
fusiform
  initials
  RAY
SYSTEM
–
originates
from
ray
initia...
GYMNOSPERM
WOOD
  AXIAL
SYSTEM
    tracheids

    fiber‐tracheids
    axial
parenchyma
  RAY
SYSTEM
    may
be
compo...
The
gymnosperm
wood

Pine
wood
in
cross
section

  HOMOCELLULAR
RAY

  HETEROCELLULAR
RAY
  resin
ducts‐
in
axial
system
or
both
axial
system
  and
ray
system

Pine
wood

ANGIOSPERM
WOOD
  more
complex
than
gymnosperm
wood
DISTRIBUTION
OF
VESSELS
  1. 
 DIFFUSE 
 POROUS‐ 
 essentially 
 equ...
Angiosperm
wood

Secondary
xylem
of
Populus
deltoides

Wood
of
Quercus
alba

DISTRIBUTION
OF
AXIAL
PARENCHYMA
  1.

APOTRACHEAL
TYPE‐
the
position
of
  parenchyma
is
independent
of
that
of
vessels
 ...
Portion
of
the
Wood
of
Quercus
alba

Apotracheal
banded

Secondary
xylem
of
Zygophyllum
dumosum

  2.

PARATRACHEAL
TYPE‐the
two
kinds
of
   elements
are
associated
with
one
another

    A.

SCANTY
‐
occasional
parenc...
scanty
   vasicentric

STRUCTURE
OF
RAY
  with
ray
parenchyma
only
  HOMOCELLULAR
RAY
–
if
it
contains
only
  procumbent
or
upright
ray
  HETE...
SECONDARY
GROWTH
IN
MONOCOTYLEDONS
  the
activity
of
this
meristem
resembles
that
     concerned
with
the
primary
thicken...
Primary
thickening
meristem

SECONDARY
GROWTH
IN
MONOCOTYLEDONS

COMMON
FORMS
OF
20

GROWTH
  1. 
 
 The 
 10 
 vascular 
 tissues 
 form 
 an 
 almost
   continuous 
 vascular 
 cylinde...
Young
stem
of
Tilia

Old
stem
of
Tilia

ANOMALOUS
20
GROWTH


  Deviating
methods
of
20
thickening

  Less
common
growth
patterns
among
plants
  investigated
th...
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
Lesson 13 bio101 (c)Dr.  Evangelista
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Lesson 13 bio101 (c)Dr. Evangelista

  1. 1. Stem

  2. 2. FUNCTIONS
  1.

Conduction
of
food
and
water
  2.

Formation
and
support
of
leaves
and
buds

  3.

Storage
of
food
ORIGIN
OF
STEMS
  Epicotyl
is
the
embryonic
origin
of
stems
  Plumule
is
the
first
bud

  The
2
terms
are








































































 sometimes
used








































 synanymously

  3. 3. EXTERNAL
STRUCTURE
OF
STEMS
  Nodes
  Internodes
  Leaves
  Buds
  Leaf
scar

  Vascular
bundle
scar

  Bud
scales
  Bud
scale
scar
  Lenticels

  4. 4. Primary
growth
of
the
plant
body

  5. 5. ProtodermGround meristemProcambium
  6. 6. PRIMARY
PERMANENT
TISSUES

  7. 7. PRIMARY
PERMANENT
TISSUES
  1.

Epidermis

  2.

Cortex
  3.


Vascular
tissues
  4.

Pith

  5.


Endodermis
  6.

Pericycle

  8. 8.   
3.
Vascular
tissues
   A.

Primary
xylem
  Protoxylem
–

  First
part
of
the
10
xylem
to
mature
  Made
up
of
tracheary
elements
and
 parenchyma
  
Metaxylem‐

  Later
part
of
the
10
xylem
to
mature
  With
tracheary
elements,
parenchyma
 and
fibers

  9. 9. Primary
xylem
development
  EXARCH
–
First
xylem
elements
to
mature
are
 farthest
from
the
center
of
the
axis;
 maturation
in
centripetal
direction


  ENDARCH‐
The
initial
elements
occur
nearest,
 and
the
latest
farthest,
from
the
center
of
the
 axis;
maturation
is
centrifugal
  3.
MESARCH
–
Differentiation
progresses
in
2
 or
more
directions
from
the
first
mature
xylem
 elements

  10. 10. Primary
xylem
development
Left
to
right‐



A.

Lycopodium
flabelliforme
rhizome;
B.

Osmunda
;



























C.

Quercus
stem




  11. 11. B.
PRIMARY
PHLOEM
  PROTOPHLOEM‐
With
sieve
elements,
may
 have
no
companion
cells;
function
for
a
short
 period
of
time,
destroyed
in
rapidly
elongating
 organs
  METAPHLOEM
‐
With
sieve
elements,
 companion
cells
and
parenchyma;
in
dicots
 fibers
are
absent

  CENTRIPETAL
DIRECTION
of
differentiation

  CENTRIFUGAL
DIRECTION
of
differentiation



  12. 12. Primary
phloem
in
Zea
mays

  13. 13. Vascular
bundle
of
Ranunculus

  14. 14. Ricinus
hypocotyl

  15. 15. Vascular
bundle
in
Cucurbita
maxima

  16. 16. VASCULAR
BUNDLES‐
Strands
of
conducting
 tissue
TYPES:
  A.

COLLATERAL
BUNDLE‐
A
bundle
with
 phloem
on
one
side
of
xylem
only,
commonly
 external
to
it
   
1.

CLOSED
–Without
vascular
cambium
   
2.

OPEN‐
With
vascular
cambium
  B.

BICOLLATERAL
BUNDLE‐
A
bundle
with
 phloem
on
both
sides
of
the
xylem

  17. 17. VASCULAR
BUNDLES
TYPES:
  C.

CONCENTRIC
BUNDLES
–
A
bundle
where
 one
vascular
tissue
surrounds
the
other
   1.
AMPHIVASAL‐
A
bundle
where
the
xylem
 surrounds
the
phloem
   2.
AMPHICRIBRAL
–
A
bundle
where
the
 phloem
surrounds
the
xylem

  18. 18. Types
of
bundle

  19. 19. Types
of
bundle

  20. 20. PRIMARY
PERMANENT
TISSUES
  1.

Epidermis

  2.

Cortex
  3.


Vascular
tissues
  4.

Pith

  5.


Endodermis
  6.

Pericycle

  21. 21.   4.

PITH
  5.

ENDODERMIS‐
the
innermost
layer
of
the
 cortex
  6.
PERICYCLE‐
the
fundamental
tissue
of
the
 stele;
the
fundamental
tissue
between
the
 endodermis
and
the
vascular
cylinder
  STELE‐
made
up
of
the
vascular
system
and
 conjunctive
tissue



(interfascicular
regions,
 the
gaps,
the
pith,
if
present)
and
the
pericycle

  22. 22. Starch
sheath
in
Ricinus

  23. 23. Perivascular
fibers
in
Cucurbita

  24. 24. TYPES

OF
STELE
  PROTOSTELE‐
Solid
column
of
vascular
tissue
 without
pith

   A.
HAPLOSTELE
–solid
core
of
xylem
 surrounded
by
the
phloem



e.g.,
Selaginella
   
B.

ACTINOSTELE‐
the
xylem
tissue
is
star‐ shaped
and
surrounded
by
the
phloem

e.g.
 Psilotum
   
C.

PLECTOSTELE‐
the
xylem
strands
are
in
 longitudinal
files
or
in
a
platelike
arrangement
 and
the
phloem
tissues
are
interspersed
with
 the
xylem
tissues
e.g.
Lycopodium

  25. 25.   TYPES

OF
STELE
  SIPHONOSTELE‐
vascular
tissue
surrounds
a
 non‐vascular
core,
the
pith
   A.

ECTOPHLOIC
SIPHONOSTELE‐
the
 phloem
occurs
outside
the
xylem
cylinder
   B.

AMPHIPHLOIC
SIPHONOSTELE
 (SOLENOSTELE)‐
the
phloem
differentiates
 outside
and
inside
the
xylem
cylinder
  DICTYOSTELE‐
a
siphonostele
in
which
large
 gaps
are
large
so
that
stele
is
divided
into
 separate
bundles

  26. 26.   EUSTELE‐
a
stele
with
interfascicular
 parenchyma
and
collateral
or
bicollateral
 bundles
  ATACTOSTELE‐
a
stele
with
scattered
bundles



  27. 27. NODES
AND
INTERNODES
(ANATOMY)
  1.
Differ
in
arrangement
of
vascular
tissues
   A.

LEAF
TRACE‐
a
vascular
bundle
located
in
 the
stem
but
directly
related
to
the
leaf
   B.
 
LEAF
GAP
OR
LACUNAE
‐
the
parenchyma
 region
located
adaxially
from
the
diverging
leaf
 trace

  28. 28. Leaf
trace
and
gap

  29. 29. NODES
AND
INTERNODES
(ANATOMY)
  TYPES
OF
NODE
   1.
ONE‐TRACE
UNILACULAR‐
with
a
single
 gap
and
a
single
trace
to
a
leaf
   2.
TWO‐TRACE
UNILACULAR‐
with
2
traces
 and
a
single
gap
to
a
leaf
   3.

TRILACUNAR‐
with
3
traces
and
3
gaps
to
a
 leaf
(1
median
and
2
lateral)
   4.
MULTILACUNAR‐
with
several
to
many
 gaps
and
traces
to
a
leaf

  30. 30. Types
of
node

  31. 31. Types
of
node

  32. 32. NODES
AND
INTERNODES
(ANATOMY)
  1.
Differ
in
arrangement
of
vascular
tissues
   C.
BRANCH
TRACES‐
vascular
supply
of
the
 branch
located
on
the
stem
   D.
BRANCH
GAP‐
the
parenchyma
region
in
 the
vascular
cylinder
above
the
position
where
 the
branch
trace
enters
the
branch

  33. 33. NODES
AND
INTERNODES
(ANATOMY)
  2.
The
cortical
and
pith
cells
may
be
shorter
in
 the
nodes
and
there
may
be
less
sclerenchyma
 and
more
collenchyma
  3.

If
the
pith
is
destroyed
during
the
growth
of
 the
stem,

   the
node
retains
the
pith
(nodal
diaphragm)
 while
the
internode
is
hollow

   or
series
of
horizontal
plates
of
pith
are
left
 (diaphragmed
pith)

  34. 34. Cucurbita
stem

  35. 35. PRIMARY
GROWTH
OF
THE
AXIS
  INCREASE
IN
HEIGHT
   primarily
through
growth
of
internodes
by:
  INCREASE
IN
DIAMETER
   AS
A
RESULT
OF:
  diffuse
growth
 
  cell
division
restricted
to
cortex
and
pith
  cell
division
restricted
to
primary
thickening
 meristem

  36. 36. Primary
thickening
meristem

  37. 37. Secondary
growth
of
the
plant
body

  38. 38. VASCULAR
CAMBIUM

  forms
20
vascular
tissues
  
are
highly
vacuolated
  with
primary
pit
fields
  CELL
TYPES
   FUSIFORM
INITIALS‐
elongated
with
 tapering
ends
   RAY
INITIALS
–
nearly
isodiametric,














 relatively
small
cells

  39. 39.   ARRANGEMENT
IN
TRANSECTION

   arranged
in
radial
series‐
cells
of
the
 cambial
zone
(initials
and
immediate
 derivatives)

  40. 40.   ARRANGEMENT
IN
TANGENTIAL
VIEWS
   1.
STORIED
OR
STRATIFIED
CAMBIUM
–
 fusiform
initials
in
horizontal
tiers
with
the
 ends
of
cells
appearing
at
exactly
the
same
 level
   2.
NONSTORIED
OR
NONSTRATIFIED
 CAMBIUM‐
the
fusiform
initials
are
not
in
 horizontal
tiers;
their
ends
overlap

(more
 primitive)

  41. 41. Vascular
cambium
in
tangential
section

  42. 42.   CELL
DIVISION
   1.
MULTIPLICATIVE
DIVISIONS
–
radial
 (anticlinal)
divisions
that
increase
the
number
 of
initials
   2.
ADDITIVE
DIVISIONS
–
tangential
 (periclinal)
divisions
that
contribute
cells
to
the
 secondary
xylem
and

secondary
phloem

  43. 43. Multiplicative
divisions
in
fusiform
initials

  44. 44.   DEVELOPMENTAL
CHANGES
   New
rays
may
arise
from
fusiform
initials
or
 their
segments
  1.


from
the
apex
of
fusiform
initial

  2.


from
the
side
of
fusiform
initial
  3.

by
transverse
divisions
of
a
fusiform
initial

  INCREASE
IN
WIDTH
AND
HEIGHT
OF
RAYS
 MAY
RESULT
FROM:
   1.

radial
divisions
of
a
ray
initial
   2.

fusion
of
2
or
more
groups
of
ray
initials
(by
 changes
in
the
intervening
fusiform
initials
 (loss
of
some,
division
and
conversion

to
ray
 of
others)

  45. 45. Origin
of
rays
from
fusiform
initials

  46. 46. Increase
in
width
of
ray

  47. 47. Increase
in
height
of
ray

  48. 48. Increase
in
height
of
ray

  49. 49.   SPLITTING
OF
RAYS
   1.

through
intrusive
growth
of
fusiform
initials
 from
a
group
of
ray
initials
   2.
through
elongation
of
ray
initials
into
 fusiform
initials
is
less
common
  LOSS
OF
INITIALS

   1.
FUSIFORM
INITIALS
  A.

conversion

to
ray
initials

  B.

maturation
into
20
xylem
or

20
phloem
 elements

  50. 50. Splitting
of
rays

  51. 51.   LOSS
OF
INITIAL

   2.
RAY
INITIALS
  A.
maturation
into
20
xylem
or

20
phloem
 elements

  52. 52. STORIED
AND
NONSTORIED
WOODS
  1)

NONSTORIED
CAMBIUM
‐
forms
nonstoried
wood
  2)

STORIED
CAMBIUM
–
forms
storied
or
nonstoried
 wood
GROWTH
RINGS/ANNUAL
RINGS
  EARLY
WOOD
(SPRING
WOOD)
–
less
dense,
 larger
cells
and
smaller
amount
of
wall
substance
  LATE
WOOD
(SUMMER
WOOD)
–smaller
cells
with
 thicker
walls



  53. 53. Vascular
cambium
in
tangential
section

  54. 54. Earlywood
and
latewood

  55. 55. Earlywood
and
latewood

  56. 56. SAPWOOD/HEARTWOOD
  SAPWOOD‐
functional
part
of
the
20
xylem
  HEARTWOOD
–
non‐functional
part
of
the
20
 xylem

  57. 57. SECONDARY
VASCULAR
TISSUES
  AXIAL
SYSTEM
–originates
from
fusiform
 initials
  RAY
SYSTEM
–
originates
from
ray
initials

  58. 58. GYMNOSPERM
WOOD
  AXIAL
SYSTEM
   tracheids

   fiber‐tracheids
   axial
parenchyma
  RAY
SYSTEM
   may
be
composed
of
ray
parenchyma
only
or
 with
ray
tracheids
  ray
parenchyma
  ray
tracheids‐
with
bordered
pits
and
lack
of
 protoplast;
with
lignified
walls;
occur
at
the
 margins
of
ray

  59. 59. The
gymnosperm
wood

  60. 60. Pine
wood
in
cross
section

  61. 61.   HOMOCELLULAR
RAY

  HETEROCELLULAR
RAY
  resin
ducts‐
in
axial
system
or
both
axial
system
 and
ray
system

  62. 62. Pine
wood

  63. 63. ANGIOSPERM
WOOD
  more
complex
than
gymnosperm
wood
DISTRIBUTION
OF
VESSELS
  1. 
 DIFFUSE 
 POROUS‐ 
 essentially 
 equal
 diameters 
 of 
 vessels 
 and 
 uniformly 
 distributed
 through
a
growth
ring
  2. 
 RING 
 POROUS 
 – 
 with 
 vessels 
 of 
 unequal
 diameters;
with
the
largest
vessels
localized
in
 early
wood

  64. 64. Angiosperm
wood

  65. 65. Secondary
xylem
of
Populus
deltoides

  66. 66. Wood
of
Quercus
alba

  67. 67. DISTRIBUTION
OF
AXIAL
PARENCHYMA
  1.

APOTRACHEAL
TYPE‐
the
position
of
 parenchyma
is
independent
of
that
of
vessels
   A.

DIFFUSE
–
dispersed
throughout
the
 

 
 
 


growth
ring
   B.

BANDED
–
appear
in
bands
   
C.

MARGINAL
–
limited
to
the
periphery
   
1)

INITIAL
PARENCHYMA
–
restricted
to
 the
beginning
of
a
seasonal
increment
  
2)TERMINAL
PARENCHYMA‐
restricted
to
 the
end
of
a

seasonal
increment

  68. 68. Portion
of
the
Wood
of
Quercus
alba

  69. 69. Apotracheal
banded

  70. 70. Secondary
xylem
of
Zygophyllum
dumosum

  71. 71.   2.

PARATRACHEAL
TYPE‐the
two
kinds
of
 elements
are
associated
with
one
another

   A.

SCANTY
‐
occasional
parenchyma
cells
 associated
with
the
vessels
   B.

VASICENTRIC‐
surrounding
the
vessel
   C.

ALIFORM
–
vasicentric
with
wing‐like
 tangential
extensions
   D.CONFLUENT 
 – 
 coalesced 
 aliform 
 with
 forming
irregular
tangential
or
diagonal
bands

  72. 72. scanty
 vasicentric

  73. 73. STRUCTURE
OF
RAY
  with
ray
parenchyma
only
  HOMOCELLULAR
RAY
–
if
it
contains
only
 procumbent
or
upright
ray
  HETEROCELLULAR
RAY
–
if
it
contains
both
 types
morphologically
RAY
SYSTEM
  HOMOGENEOUS
RAY
–rays
are
all
homocellular
  HETEROGENEOUS
RAY
–
rays
are
all
 heterocellular
or
some
are
homocellular,
others
 heterocellular


  74. 74. SECONDARY
GROWTH
IN
MONOCOTYLEDONS
  the
activity
of
this
meristem
resembles
that
 concerned
with
the
primary
thickening
in
some
 monocots
  these
meristems
may
be
developmentally
 continuous
if
found
in
the
same
plant
TYPES
OF
20
GROWTH
IN
MONOCOTS
  diffuse
20
growth
through
division
and
 enlargement
of
ground
parenchyma
(e.g.
palms)
  20
growth
from
a
restricted
meristem
(cambium)
 formed
in
the
cortex
outside
the
vascular
 bundles
(herbaceous
and
woody
Liliflorae
e.g.
 Aloe,
Sansevieria,
Yucca,
Agave,
Dracaena)



  75. 75. Primary
thickening
meristem

  76. 76. SECONDARY
GROWTH
IN
MONOCOTYLEDONS

  77. 77. COMMON
FORMS
OF
20

GROWTH
  1. 
 
 The 
 10 
 vascular 
 tissues 
 form 
 an 
 almost
 continuous 
 vascular 
 cylinder 
 and 
 the 
 20
 vascular
tissues
do
the
same
  2. 
 
 The 
 10 
 vascular 
 tissues 
 form 
 a 
 system 
 of
 strands,
but
the
20 
vascular
tissues
arise
as
a
 continuous
ring


  78. 78. Young
stem
of
Tilia

  79. 79. Old
stem
of
Tilia

  80. 80. ANOMALOUS
20
GROWTH


  Deviating
methods
of
20
thickening

  Less
common
growth
patterns
among
plants
 investigated
thus
far


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