Fig' 24CO b, p' 426

1
Gymnosperms
Fig. 24-CO (b), p. 426
2
Conifers
Cephalotaxaceae
Podocarpaceae
Taxaceae
Cupressaceae
Sciadopityaceae
Araucariaceae
Gnetophytes
Pinaceae
Gnetum
Welwitschia
Ephedra
Flowering plants
Ginkgo
Cycads
(Seed ferns)
Progymnosperms
(Archaeopteris)
seeds
Monilophytes
wood
Fig. 24-1, p. 427
Earliest Tracheophytes
3
Cycads
125 species occur mainly in tropics U.S. Zamia
integrifolia
Highest species diversity about 200 million years
ago (dinosaur food).

• slow growing
• rarely branched, palmlike appearance (compound
  leaves)
• dioecious, large ovulate cones
• large percentage of parenchyma in xylem

4
Cycads
Cycas revoluta sago palm

• Sago
• starch from the pith of the stems (after removal
  of poisonous compounds)
• granular food thickener

5
Conifers
Cephalotaxaceae
Podocarpaceae
Taxaceae
Cupressaceae
Sciadopityaceae
Araucariaceae
Gnetophytes
Pinaceae
Gnetum
Welwitschia
Ephedra
Flowering plants
Ginkgo
Cycads
(Seed ferns)
Progymnosperms
(Archaeopteris)
seeds
Monilophytes
wood
Fig. 24-1, p. 427
Earliest Tracheophytes
6
Ginkgo
1 species Ginkgo biloba maidenhair tree
extant occurance in warm-temperate forests of
China

• branching tree with two-lobed leaf blades and
  dense wood
• dioecious, ovules on stalks, male strobilus

• medicinal (brain-circulation) and ornamental tree
• seed coats have a bad smell

Fig. 24-9, p. 433
7
Conifers
Cephalotaxaceae
Podocarpaceae
Taxaceae
Cupressaceae
Sciadopityaceae
Araucariaceae
Gnetophytes
Pinaceae
Gnetum
Welwitschia
Ephedra
Flowering plants
Ginkgo
Cycads
(Seed ferns)
Progymnosperms
(Archaeopteris)
seeds
Monilophytes
wood
Fig. 24-1, p. 427
Earliest Tracheophytes
8
Gnetophytes
Welwitschia
3 genera
Ephedra (U.S.)
ovule surrounded by bracts
Gnetum
Fig. 24-23, p. 444
9
Gnetophytes

• Similarities to flowering plants (convergent
  evolution or close relationship?)
• Vessel elements in xylem
• Ovules surrounded by fleshy tissue
• Stamen-like structures
• Reduced gametophyte
• Double fertilization

10

• Welwitschia
• Namib desert
• up to 2000 years old
• two fragmented leaves that continuously grow from
  their base
• large tap root

cones
fragmented leaf
Fig. 24-24 (a), p. 445
11
Conifers
Cephalotaxaceae
Podocarpaceae
Taxaceae
Cupressaceae
Sciadopityaceae
Araucariaceae
Gnetophytes
Pinaceae
Gnetum
Welwitschia
Ephedra
Flowering plants
Ginkgo
Cycads
(Seed ferns)
Progymnosperms
(Archaeopteris)
seeds
Monilophytes
wood
Fig. 24-1, p. 427
Earliest Tracheophytes
12
Conifers
cone bearers (woody seed cones) closed cone
species depend on fire about 650 species leaves
are needle- or scale like
Fig. 24-2, p. 428
13
sciadopityaceae
cephalotaxaceae
podocarpaceae
araucariaceae
cupressaceae
pinaceae
taxaceae
Conifers
Araucaria
Fig. 24-10, p. 433
14
Taxaceae
only conifers without cones seeds are surrounded
by a fleshy tissue (aril)
U.S. Pacific Yew Taxus brevifolia contains
anticancer compound Taxol
Fig. 24-16, p. 437
15
Pinaceae

• needle-like leaves borne singly or in clusters
  (fascicles) on a special short shoot
• usually monoecious
• woody cones with two winged seeds per scale
• genera Pinus (pines), Abies (firs), Picea
  (spruces), Tsuga (hemlocks), Pseudotsuga (Douglas
  firs), Larix (larches and tamaracks), Cedrus
  (cedars)

16
Pinaceae
Pinus (pine) 2-5 needles per fascicle cones are
hanging and shed intact at maturity
Fig. 24-11, p. 434
17
Pinaceae
Abies (firs) singly-borne flat and blunt
needles erect seed cones that shatter/disintegra
te at maturity (do not fall as a unit)
Fig. 24-12, p. 434
18
Pinaceae
Picea (spruce) singly-borne, angular, and
sharply pointed needles pendant seed cones,
which fall as a unit when mature
Fig. 24-13, p. 435
19
Pinaceae
bract
Pseudotsuga (Douglas firs) pendant cones with
three-lobed bracts soft needles timber tree
Pseudotsuga menziesii
Tsuga (hemlocks) pendant cones short needles
Fig. 24-14, p. 435
20
Pinaceae
Larix (larches and tamaracks) deciduous,
needles are all shed in fall singly-borne
needles on new branches, needle clusters on old
branches
21
Pinaceae
Cedrus (cedars) erect cones that
disintegrate needles born singly or in
fascicles important timber and ornamental trees
22
Cupressaceae

• often scalelike leaves
• monoecious or dioecious
• woody or fleshy cone scales with 2 seeds per
  scale
• U.S. Juniperus, Sequoia (coast redwood),
  Sequoiadendron (Sierra redwood), Taxodium (bald
  cypress, deciduous), Thuja ( red cedar,
  arborvitae)

Fig. 24-15, p. 435
23
Coast Redwood (Sequoia sempervirens)
Together with the Australian Eucalyptus the
tallest tree species on Earth
Appearance Tall 65-115 m Straigth trunk with
diameter of 3-5 m (max. 10m) Lower 2/3 of trunk
are branchless when mature Straight
branches Furrowed bark
Juvenile
Mature
24
Coast Redwood (Sequoia sempervirens)
Redwood branchlets
Leaves evergreen, linear, spreading,
2-ranked, 6-20 mm long
25
Coast Redwood (Sequoia sempervirens)
Cones 19-25 mm, 12-20 scales, woody, hard
Seeds winged, 1.5-2.5 mm
Bark reddish-brown, deeply furrowed, 15-30 cm
thick
Termite-resistant wood
26
Coast Redwood (Sequoia sempervirens)
Habitat redwood groves in moist plains and foggy
slopes at the Pacific coast of California and
Oregon Redwood National Park
27
Giant Sequoia (Sequoiadendron giganteum)
The biggest life form on Earth
Appearance Tall 60-105 m Massive Trunk is
6-15 m in diameter and weighs up to 2000
tons Reddish-brown bark is 30-60 cm thick
General Grant
Juvenile
Seedling
General Sherman
28
Giant Sequoia (Sequoiadendron giganteum)
Leaves 3-6 mm long Overlapping Closely pressed
to branchlets
29
Giant Sequoia (Sequoiadendron giganteum)
Cones 38-63 mm, egg-shaped, woody, with 25 to 40
scales
Seeds 3-6 mm, lance-shaped, with 2
wings encircling the seed
Bark 30-60 cm thick, reddish-brown,
deeply furrowed
30
Giant Sequoia (Sequoiadendron giganteum)
The Sierra Nevada in California, Painting by
Albert Bierstadt
Habitat Dry high altitude ranges of the Sierra
Nevada National Parks General Grant, Kings,
Sequoia, Yosemite
31
Bald Cypress (Taxodium distichum)
a decidous conifer
Appearance 20-45 m tall Trunk diameter 1.5 m
(max 4 m) Trunk base strongly buttressed Roots
form aerial knees when growing in
water. Deciduous except in southernmost habitats
root knees
young tree
old trees
32
Bald Cypress (Taxodium distichum)
Leaves linear, thin, 2-ranked, spreading, 12-19
mm long deciduous, light yellow-green in summer,
become reddish-brown during fall
33
Bald Cypress (Taxodium distichum)
Cone 22-28 mm
Bark 2.5-5 cm thick
Seeds irregularly 3-angeled, 8-10 mm with 3
narrow wings
34
Bald Cypress (Taxodium distichum)
US Distribution
Habitat usually swamps and moist lowlands, but
tolerates also much drier soil and makes an
attractive park tree
35
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