20. Plants are often required to attain
a minimum height at maturity to
qualify as trees (usually between 3
and 6 meters tall).
Photograph: Chris Mullins
21. secondary thickening Woody plants are capable of
secondary thickening, adding new
yearly growth layers of cells onto the
accumulated growth of previous years.
25. tissue containing plant ‘stem’ cells
vascular cambium 1 a lateral meristem in the vascular tissue of plants.
2 the source of both the secondary xylem (inwards,
towards the pith) and the secondary phloem
(outwards), and located between these tissues in
the stem and root.
53. Tracheids
Scots pine
Pinus sylvestris
Photograph: Fritz Schweingruber
54. tracheids 1 elongated cells that function in food conduction
and structural support.
2 most common type of cell in conifers. Much less
frequent in deciduous trees.
55.
56. large cells
thin cell walls
small cells
thick cell walls
Scots pine
Pinus sylvestris
Photograph: Fritz Schweingruber
57. Ray
Scots pine
Pinus sylvestris
Photograph: Fritz Schweingruber
58. rays 1 fla ened bands of tissue that extend horizontally
in a radial plane through the tree stem.
2 transport sap and wastes produced by
photosynthesis.
65. English oak
Quercus robur
Photograph: Fritz Schweingruber
66. Earlywood vessels
English oak
Quercus robur
Photograph: Fritz Schweingruber
67. English oak
Quercus robur
Photograph: Fritz Schweingruber
68. Latewood
vessels
English oak
Quercus robur
Photograph: Fritz Schweingruber
69. vessel element 1 a type of hardwood cell that has a relatively
large diameter, thick cell wall and perforate
(open) ends.
2 combines to form ‘vessels’, long passageways
used to conduct water and soluble nutrients.
70. ring porous a hardwood with (1) relatively large vessels
in the earlywood and (2) distinctly smaller
pores in the latewood.
71. Fibre
English oak
Quercus robur
Photograph: Fritz Schweingruber
72. fibre an elongated hardwood cell with thick walls
that contributes greatly to the material
strength of wood.
73. Ray
English oak
Quercus robur
Photograph: Fri sSchweingruber
Fritz Schweingruber
74. American elm
Ulmus americana
Photograph: daryl_mitchell
75. diffuse porous a hardwood with vessels that are
approximately the same size and
distributed (fairly) evenly throughout the
growth ring.
76. Sycamore maple
Acer pseudoplatanus
Photograph: Fritz Schweingruber
77. European beech
Fagus sylvatica
Photograph: Fritz Schweingruber
