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The conifers have the
Most massive =
Giant Sequoias
Sequoiadendron giganteum
(Cupressaceae)
…...
..The Tallest = Coastal
Redwood (Sequoia
sempervirens)
(Cupressaceae)
….
.. And the oldest = Bristlecone Pine
Pinus longaeva (Pinaceae).
Welwitschia
mirabilis
Welwitschiaceae
young plant
Note 2 strap-like
leaves
http://waynesword.palomar.edu/images/welwit3b.gif
As Welwitschia grows the 2 leaves split into many sections.
http://www.biosci.ohio-state.edu/~plantbio/images/greenhouseimages/welwitschia2.jpg
Welwitschia is dioecious with
separate male and female
plants.
Plant with female
cones
Plant with
male
cones
Welwitschia mirabilis can live for up to 2000 years by which
time the two leaves have shredded into multiple straps.
ttp://www.cactusandsucculent.org/riviste/2000/fascicolo-4/foto/welwitschia-mirabilis.jpg
Courtesy of Amy Dieckmann ‘05
Escalante National Monument, Ephedra in the foreground
http://www.ut.blm.gov/monument/Science_and_Research/pictures/ephedra.jpg
Plant
Male strobili (“cones”)
Ephedra
Female strobilus (“cone”)
From Tree of Life Web Site, U. of AZ
Gnetum, a woody plant with vessels
Gnetophytes and Angiosperms have vessels.
a. Longitudinal
tracheid of
pine.
b. Vessel of a
hardwood
(early wood)
c. Vessel of
a hardwood
(late wood)
c. Hardwood
fiber cell
(provides
support)
e. Trachied of
a hardwood.
Anthophyte
Hypothesis
Gnetifer
Hypothesis
Two trees illustrating the Anthophyte vs Gnetifer Hypotheses
Anthophytes
(Extinct)
(Extinct)
Gnetifers