Download View/Open

Taxodium
Native of Mexico and North America
Having deciduous leaves
Taxodium ascendens – the pond cypress
T. distichum – the bald cypress
T. mucronatum –the Montezuma yew cypress
Taxodium
mucronatum
‘Big tree of Tule’
16m in diameter
5,000 years old (probably the oldest living thing in the world)
Unlike other cypress, this is evergreen
Does not possess a single dead twig
Girth 58 meters
Height 42 meters
Position
Family – Cupressaceae
Subfamily – Taxodiaceae (Trees that are evergreen or deciduous)
10 members under subfamily
Athrotaxis (3)
Cryptomeria (1)
Cunninghamia (2)
Glyptostrobus (1)
Metasequoia (1)
Sciadopitys (1)
Sequoia (1)
Sequoiadendron (1)
Taiwania(1)
Taxodium (3)
•Monoecious
•Ovuliferous scales are free almost
free when young
•2-9 ovules on each ovuliferous scale
•2-9microspoangiaor pollen sacs on
each microsporophyl
•Pollen grains are without wings
•Pollen grains lack prothallial cells
Ecology
T. adnascens: The Pond Cypress occurs within the range of Bald
Cypress, but only on the southeastern coastal plain from North
Carolina to Louisiana. It occurs in still backwater rivers, ponds and
swamps without silt-rich flood deposits.
T. mucronatum: The Montezuma Cypress occurs from the
Lower Rio Grande Valley south to the highlands of
southern Mexico, and differs from the other two species in being
substantially evergreen. t is a riparian tree, occurring on the banks
of streams and rivers, not in swamps like the Bald and Pond
Cypresses
T. distichum: The most familiar species in the genus is the Bald
Cypress, native to much of the south-eastern United States, from
Delaware to Texas, especially Louisiana and inland up
the Mississippi River to southern Indiana. It occurs mainly along
rivers with silt-rich flood deposits.
Morphology
The persistent branches with axillary buds near the ends of
the year’s growth
Two types of branches
The deciduous branches attached to the persistent shoots but
without axillary buds
Leaves are soft, short, narrow and pointed and show two types
of on the shoots arrangements
On the persistent shoots are spirally arranged; on the deciduous
shoots are two ranked
Winter buds are small , round with overlapping, sharp and
pointed scales occurring near the tip of the shoot
Bark is green when young, turns brown and scaly in older trees
Leaves at first glance appear compound-in reality, they are simple.
The needles are arranged in two ranks
(that is, they occur in exactly two rows on
each side of the stem)--this is called
distichous (hence the epithet distichum).
Cypress Knees
Plants that grow in swamps or marshy places have knee like out
growths from roots arising vertically above the soil for about 1-3.5m
in known as ‘Cypress knees’
Knees are soft and spongy
Perform same function as
pneumatophores or breathing
roots
Lower part of the trunk shows
extreme swellings and is
profusely
covered
with
adventitious roots
Knees shows 6-8 xylem groups
Normal roots are diarch
Stem Anatomy
Anatomy of 5-year old stem: pith and 1st wood
growth ring (primary xylem indicated with
arrow)
annual growth rings
growth ring, tracheid, ray
TLS of Wood
RLS of Wood
Form: A large tree with a pyramid-shaped crown,
cylindrical bole, fluted or buttressed base and often
with knees
Monoecious – male and female cones generally
on different branches
Flowers: Males in drooping, long panicles;
females are sub globose, have peltate scales, and
tend to occur near the end of branches.
Fruit: Cones are composed of peltate scales
forming a woody, brown sphere with rough
surfaces, 3/4 to 1 inch in diameter; cones
disintegrate into irregular seeds.
Cone Characteristics
•Cones appear near the tips of the branches of the same year and
are found in the axil of the scale leaves
•Female cone are irregularly placed on shoots and occur in groups
of two or three
•Male cones are long drooping panicles
•Female cones are ball shaped
Male cone
Male cone is small, round gradually turns to oblong on
maturity
Colour – green to yellow to dark brown at maturity
10-15 stalked microsporophylls with a broad base spirally
arranged on the cone axis
Microsporophylls are surrounded by ovate scales
Each microsporophylls bears 8 or 9
microsporangia in two rows on its abaxial side
Before polen dispersal the cone axis elongate to
expose the individual sporangia
Sporophylls bears stomata on the lower surface
and resin ducts in the distal portion
Female cones
•Develop as inconspicuous axillary bud on shoots of the same year
•Round when young, ovoid when mature
•Each cone comprises spirally arranged overlapping bracts
•Lower and upper part bracts are sterile (do not bear ovules)
•The ovules initiate earlier than the initiation of the ovuliferous scales
•Later ovuliferous scales overgrows the ovules
•Each megasporophyll comprises the bract and ovuliferous
scale
• In mature cone they fused together at base
•Each megasporophyll bears 2-3 ovules on its adaxial surface
•After pollination the tip of the ovuliferous grows to meet the
scale above thus closing the cavity where the ovule lies
•In a cone fertile sporophyll are ten
•Seeds are dark brown, compressed, three angled and three
winged
immature female cones-these are fleshy
and green while they develop..
and they will eventually darken to a brown color, and then dry
out at maturity.
Male cell
Part of ovule showing pollen tube
Pollen tube near the archegonial complex
L.S thru archegonia complex
Egg nucleus
Stage of fertilization – fusion of
male and female gametes
A: L.S. of seed showing mature embryo
B-D: Progressive stage in the development of seed coat
Cupressus
Common Name : Mediterranean cypress, common cypress, Italian cypress
Family : Cupressaceae
Subfamily: Cupressoideae
The common name comes from
Old French cipres and that
from Latin cyparissus which is
the latinisation of the Greek
Kuparissos
Family Cupressaceae
•Much branched evergreen trees to shrubs
•Plant parts are arranged in opposite and deccusate manner or in whorls of 3 or 4
•Juvenile leaves – linear or spreading (present in seedling and on mature trees)
•Leaves are adnate or adpressed hiding the stem
•They are glandular or grooved on the abaxial side
•Monoecious
•Fusion between bract scale and ovuliferous scale prominent
•Ovules are erect, 3-20
•Female cones woody at maturity
•Seeds may be winged or wingless
•Male cone are catkin like, solitary, axillary or terminal
•Pollen sacs 3-6
•Pollen lack prothallial cells, wings and sacci
22 genera 150 species
11 are monotypic
Half of the genera have distribution in
southern hemisphere and half in northern
hemisphere
Cupressus Distribution
cypresses are native to scattered localities in mainly warm temperate regions in the
Northern Hemisphere, including North western America, Central America,
northwest Africa, the Middle East, the Himalayas, southern China and northern
Vietnam
12 speceis of Cupressus distributed
C. torulosa is native occurring in the Himalayas from Chamba In H.P to Nepal at an altitude
of 1800-2800m
Other common planted species in India are C. funebris, C. cashmeriana C. sempervirens, C.
macrocarpa and C. lusitanica
C. funebris found growing near cemeteries and monasteries and is known as the “chinese
weeping cypress” or “funeral cypress”
Ecology
This species is also tolerant to drought, air currents, wind dust,
sleet and atmospheric gases. Its root system is well developed. It
succeeds on acid and alkaline soils
Morphology
•Evergreen tree
•15-20m height with pyramidal appearance
•Bark thin, fibrous, greyish brown and peels off in long strips
•Branching two types
horizontal or erect main branches spirally arranged on the main stem
drooping side branches – weeping branches
•Main branches devoid of leaves; drooping
branches bear small, opposite, decussate leaves
adpressed to the axis
•Lateral pair of leaves folded face to face and
facial pair are flattened and grooved in the middle
•Two types of leaves
Apical zone- small, closely placed, apex acute,
serrated margin
Mature leaves –longer, brownish and distantly
placed
•Leaves have prominent midrib and scattered
stomata on both the surfaces
T.S. of wood
Monoecious
Reproduction
•Male cone 6-7 mm long
•Terminally on pendulous branches
•Yellow to brown when mature
Twig bearing male and female cone
Male cone
Abaxial
Microsporophyll
Adaxial
•6-8 pairs of microsporophylls
•Each bearing 2-6 sporangia abaxially
•Sporophylls are arranged opposite,
decussate manner on the cone axis
•No prothalli cells are formed
•Pollen are non winged
Develop,ment of spore tetrad and pollen
Male cone releasing pollen
Female cone
•Female cones are 10-12mm long
•Axillary on the pendulous branch
•Each consists of four pairs of seed scale complexes arranged in an opposite ,
decussate manner
•Lowermost pair is generally sterile
•Fertile scales are peltate bears 3-7 ovules or seeds per scale
•Fertile seed scale complexes are thick, 4-6
sided with a central pointed structure
called boss
•Mature cone is woody and peristent
•Seeds
are
dark
brown,
orbicular,
compressed and narrowly winged
•The wings of successive seeds overlap