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Abstract (Student Project 4 - Botany on Pui O Beach)

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Prepared by
Sacred Heart Canossian College
Field Trip on Pui O Beach
for Botany on Sandy Beaches

Team Members
Cindy Kwok
Queenie Ching
Kathy Chin
Angel Koo
Judy Kwok
Jessica Chow
Kristin Wong
Karen Chow
LilianYeung
Villana Lo
Maggie Yeung

‧PuiO Beach, located between
Cheung ShaBeach and Chi Ma Wan
Peninsula in southern LantauIsland,
exhibits a harsh habitat
‧It is introduced as an example to
study the plant adaptations to
xerophyticenvironment in HK
Introduction
Environmental pressure of Sandy Beach
..Soil
..Low nutrient supply
..Poor anchorage
..Sunlight
..High irradiation leads to closure of stomata
..Little shading and high reflection by sand
..Temperature
..Wide range of temperature fluctuation at
ground levelEnvironmental pressure ofSandy BeachEnvironmental pressure ofSandy Beach

..Herbivores/ Human impacts
..Exposure to herbivores
..Human trampling leads to reduction in
vegetative coverage
Environmental pressure of Sandy Beach
Vitex rotundifolia(白背蔓荊)
General Information:
‧Family: Verbenaceae

Vitex rotundifolia(白背蔓荊)
Feature1:
‧Hairylower leaves
surfaceAdaptations:
1.Reduce water loss2.Minimize the
secondary reflection
of sunlight (by sea
water and sand)White hair on abaxialside

Feature 2:
‧Prostrate stems
rooting at nodes
Adaptations:
1.Stems spread
extensively for better
anchorage and
exploration for water
2.Shallow roots system
allows effective
absorption of rainwater
and colonization
Vitex rotundifolia(白背蔓荊)

Vitex rotundifolia(白背蔓荊)
Other features:
‧Square stems‧Purplish flowers‧Leaves opposite
(對生): paired
leaves growing
on the same
level and
opposite sides
of the stem

Ipomoea pes-caprae
(厚藤/海灘牽牛)
General Information:
‧Family: Convolvulaceae
‧Common name: Beach Morning-glory

Ipomoea pes-caprae
(厚藤/海灘牽牛)
Feature 1:
‧Thick and fleshy leaves
Adaptation:
‧Increase water storage
Feature 2:
‧Fruits can float on water
Adaptation:
‧Water dispersal to colonize new areas

Ipomoea pes-caprae
(厚藤/海灘牽牛)
Other features:
‧Kidney-shaped
leaves‧Purplish trumpet-
shaped flowers

Launaeasarmentosa
(匍莖栓果菊)
General Information:
‧Family: Asteraceae

Launaeasarmentosa
(匍莖栓果菊)
Feature 1:
‧Rosette leaves
Adaptation:
‧Lying low to
avoid pruning by
wind
e.g. Rosette leaves

Feature 2:
‧Stolonpresent
Adaptations:
1.Spreading to cover
wider areas
2.Shifting sand
3.Colonization
Stolonstolon–a prostrate stem and a
colonizing organ that arises from an
axillarybud near the base of plant
Launaea sarmentosa (.m2oReaGμa)
Feature 3:
‧Milky fluid present
Adaptations:
1.Possibly for temperature buffer
against the heat in the daytime (byits high specific heat capacity)
2.Protection against herbivores
Launaea sarmentosa (.m2oReaGμa)
Other features:
‧Yellowish flowers
‧Head inflorescence
‧Reproduced by both
seeds and vegetative
growth
yellow inflorescence
Launaea sarmentosa (.m2oReaGμa)

Spinifexlittoreus(鬣刺)
General information:
‧Family: Poaceae
‧Common name: Littoral Spinegrass

Spinifexlittoreus(鬣刺)
Location & Habituation:
..lives on coastal sand
dunes
..a wind-pollinated grass
with large vegetative
colonies

Spinifexlittoreus(鬣刺)
Flowers:
‧Pistillateflowers normally have
sterile anthers.
‧Some spikeletswith pistillateflorets; whilst some spikeletswith both perfect and
staminate florets.
‧Female spikeletshave two
florets, one neuter with sterile
anthers and one pistillatewith
sterile anthers.

Pandanustectorius(露兜樹)
General information:
‧Family: Pandanaceae
‧Common name: Screw Pine

Pandanustectorius(露兜樹)
Leaves:
‧Linear leaves spirally
arranged at branch tips
‧Up to 2 m in length
‧M-shaped in cross
section
‧Midrib of lower surface
and margins prickly

Pandanustectorius(露兜樹)
Fruits:
‧Multiple fruits globose
‧Each fruit resembles a tooth
‧Wedge-shaped orange sections are edible,
husk fibrous, one to several-seeded

The fruits can float on water
Pandanustectorius(露兜樹)

Pandanustectorius(露兜樹)
Roots:
‧Prop roots for unstable substratum

Pandanustectorius(露兜樹)
Location & Habit:
‧It is a terrestrial plant growing upshorebeyond and around upper tidal zone

Pandanustectorius(露兜樹)
Uses:
‧Leaves are woven or plaited into
mats, thatch, sails, baskets, hats,
fans, and pockets for keeping
spiders used in fighting games
‧Leaves used for wrapping glutinous
rice to make rice dumplings at
Dragon Boat Festival

Agaveangustifolia
(狹葉龍舌蘭)
General information:
‧Family: Agavaceae‧Common name: Narrow-leaved Century
Plant

Growth Habits:
‧Succulent rosette
leaves
‧Up to 90 cm in
diameter
Propagation:
‧Can be propagated
by seed or vegetative
propagation.
Agave angustifolia (¯U﹐As
|TAo)

Uses:
‧In Mexico, Agaveis grown for their sap,
which is fermented to make an
alcoholic drink called tequila, and for
their fiber, which is made into cloth and
paper
‧In southern China, its fibers are used to
make ropes and fishing nets
Agave angustifolia (¯U﹐As
|TAo)
Severiniabuxifolia
(酒餅.)

General information:
‧Family: Rutaceae‧Common names: Box-leaved AtalantiaSeveriniabuxifolia(酒餅.)

Adaptation:
‧Thorny stems for
protection against
herbivores
Other feature:
‧Leavesnotched at
apex,smell like citrus
fruit
Severiniabuxifolia
(酒餅.)

Caesalpinia bonduc
General information:
‧Family: Caesalpiniaceae
‧Common name: Gray Nickers
‧Vine-like tropical shrub with
thorns covered branches
‧Often climb over other
vegetation
‧Leaves bipinnatelycompound
Caesalpinia bonduc
Fruits:
‧Prickly, flattened, oval
shaped, reddish brown
when dried
‧Bearing 1-3 seeds which
are drab in color, but, after
exposure to the sun, are
bleached to light gray in
color
Caesalpinia bonduc
Adaptations:
‧Stems thorny to protect
against herbivores
‧Seeds can float on water
for dispersal to other
beaches
Caesalpinia bonduc
Casuarinaequisetifolia
(木麻黃)

Casuarinaequisetifolia
(木麻黃)
General information:
‧Family: Casuarinaceae‧Common names: Horsetail tree, Ironwood,
Australian Pine‧A native of Australia

Casuarinaequisetifolia
(木麻黃)
Descriptions:
‧A large vase-shaped tree,
up to 35 m in height
‧Trunk covered with scaly
brownish gray bark
‧Root system is fibrous
and spreading, and may
form buttress
Leaves:
‧Leaves scale-liked,
appressedas a ring at
the branchletnodes

Fruits:
‧Multiple fruits woody,
resembling pinecones,
up to 2.5 cm in length,
each containing 70-90
winged seeds
‧Wind and water
dispersal
Casuarina equisetifolia
‧It is commonly
planted on beaches,
and coastal sites
throughout tropical
areas
Casuarina equisetifolia

Adaptations:
‧Grows well in salty, calcareous, rocky,
volcanic, granitic, or poor soils
‧Forms symbiotic nitrogen-fixing
associations with soil microbes
Casuarina equisetifolia
Paliurusramosissimus
(馬甲子)
General Information:
‧Family: Rhamnaceae‧Common name:
Thorny Wingnut

Characteristics:
1)Deciduous shrub, up to 6 m tall
2)Leaves alternate, oval in shape, margins
toothed, with 3 prominent veins extending
from the leaf base to apex
3)Flowers greenish yellow
4)Fruits cup-shaped, dry, flat-topped and hairy
5)Stems bear prickles
Paliurus ramosissimus


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