Chapter 4 Seagrass Sexual Reproduction
91
Table 2. Selected reproductive characters in seagrass genera (data from Arber, 1920; den Hartog, 1970; Ducker et al., 1978; McConchie 1982; Pettitt 1980, 1984;
Tomlinson 1982; McConchie; Knox, 1989a; Guo et al., 1990; Inglis 2000; Smith and Walker 2002).
Reproductive ecology
Staminate flower
Carpellate flower
Diaspore
Genus (# sp)
Mode
Dicliny
Arrangement
Anthers
Pollen (dimensions) Exine
Carpels
Texture
Fruit
Seed
Hydrocharitaceae
Enhalus (1)
Surface
Dioecious
Inflorescence
solitary
3 stamens, 6
tepals, free
floating
flowers
Spherical, few
large (150–175
µm)
Present 3 sepals, 6
styles
Papillate
stigma
Fleshy, ovoid
with 8–14
seeds
Not dormant,
no
endosperm,
obconical,
few in
number
Thalassia (2)
Submarine Dioecious
1–4 solitary on
inflorescence
8–12 stamens
Spherical
(80–100
µm) in
long chains
Present Hypanthia
with 2
long
stigmas
Papillate
Fleshy, globose Not dormant,
no
endosperm,
conical,
several large
Halophila (14)
Submarine Monoecious
and
dioecious
Unisexual solitary
flower
3 stamens
pedicilate
Ellipsoidal (80
×
40
µm) in linear
pollinium
Absent Long style
and
hypanthia
with 2–6
stigmas
Papillate
Fleshy, globose,
geocarpy
Dormant, no
endosperm,
globose,
several
minute
Cymodoceaceae
Amphibolis (2)
Submarine Dioecious
Solitary and
terminal naked
flower on short
lateral shoots
2 united anthers,
stalked
Filiform (3–5000
× 20
µm)
Absent 2 carpels,
each with
3 long
stigmas
Non-papillate Germination on
plant
Viviparous, no
endosperm,
seedling has
comb-like
appendage
Cymodocea (4) Submarine Dioecious
Solitary and
terminal naked
flower
2 united anthers,
stalked
Filiform (2000
×
10
µm)
?
2 carpels
each with
2 long
stigmas
Non-papillate Laterally
compressed,
geocarpy
Dormant, no
endosperm
Halodule (8)
Submarine Dioecious
Solitary and
terminal flower
2 united anthers
at different
heights,
stalked
Filiform
(1000
µm)
Absent 2 carpels,
each with
a long
stigma
Non-papillate Stony pericarp,
geocarpy
Dormant, no
endosperm
Syringodium (2) Submarine Dioecious
Cymose
inflorescence
2 united anthers,
stalked
Filiform
?
2 carpels,
each with
2 long
stigmas
Non-papillate Ellipsoidal,
stony pericarp
Dormant, no
endosperm
Thalassodendron
(2)
Submarine Dioecious
Terminal, two
flower
inflorescence
on short shoots
2 completely
united anthers
stalked
Filiform (5000
×
20
µm)
Absent 2 carpels,
each with
2 long
stigmas
Non-papillate False fruit,
fleshy bracts
Viviparous, no
endosperm,
free floating
seedling
(continued )
91
Table 2. Selected reproductive characters in seagrass genera (data from Arber, 1920; den Hartog, 1970; Ducker et al., 1978; McConchie 1982; Pettitt 1980, 1984;
Tomlinson 1982; McConchie; Knox, 1989a; Guo et al., 1990; Inglis 2000; Smith and Walker 2002).
Reproductive ecology
Staminate flower
Carpellate flower
Diaspore
Genus (# sp)
Mode
Dicliny
Arrangement
Anthers
Pollen (dimensions) Exine
Carpels
Texture
Fruit
Seed
Hydrocharitaceae
Enhalus (1)
Surface
Dioecious
Inflorescence
solitary
3 stamens, 6
tepals, free
floating
flowers
Spherical, few
large (150–175
µm)
Present 3 sepals, 6
styles
Papillate
stigma
Fleshy, ovoid
with 8–14
seeds
Not dormant,
no
endosperm,
obconical,
few in
number
Thalassia (2)
Submarine Dioecious
1–4 solitary on
inflorescence
8–12 stamens
Spherical
(80–100
µm) in
long chains
Present Hypanthia
with 2
long
stigmas
Papillate
Fleshy, globose Not dormant,
no
endosperm,
conical,
several large
Halophila (14)
Submarine Monoecious
and
dioecious
Unisexual solitary
flower
3 stamens
pedicilate
Ellipsoidal (80
×
40
µm) in linear
pollinium
Absent Long style
and
hypanthia
with 2–6
stigmas
Papillate
Fleshy, globose,
geocarpy
Dormant, no
endosperm,
globose,
several
minute
Cymodoceaceae
Amphibolis (2)
Submarine Dioecious
Solitary and
terminal naked
flower on short
lateral shoots
2 united anthers,
stalked
Filiform (3–5000
× 20
µm)
Absent 2 carpels,
each with
3 long
stigmas
Non-papillate Germination on
plant
Viviparous, no
endosperm,
seedling has
comb-like
appendage
Cymodocea (4) Submarine Dioecious
Solitary and
terminal naked
flower
2 united anthers,
stalked
Filiform (2000
×
10
µm)
?
2 carpels
each with
2 long
stigmas
Non-papillate Laterally
compressed,
geocarpy
Dormant, no
endosperm
Halodule (8)
Submarine Dioecious
Solitary and
terminal flower
2 united anthers
at different
heights,
stalked
Filiform
(1000
µm)
Absent 2 carpels,
each with
a long
stigma
Non-papillate Stony pericarp,
geocarpy
Dormant, no
endosperm
Syringodium (2) Submarine Dioecious
Cymose
inflorescence
2 united anthers,
stalked
Filiform
?
2 carpels,
each with
2 long
stigmas
Non-papillate Ellipsoidal,
stony pericarp
Dormant, no
endosperm
Thalassodendron
(2)
Submarine Dioecious
Terminal, two
flower
inflorescence
on short shoots
2 completely
united anthers
stalked
Filiform (5000
×
20
µm)
Absent 2 carpels,
each with
2 long
stigmas
Non-papillate False fruit,
fleshy bracts
Viviparous, no
endosperm,
free floating
seedling
(continued )