多肉英文介绍Succulent plant

Succulent plant

From Wikipedia, the free encyclopedia

Not to be confused with cactus; nearly all cacti are succulents but not all succulents are cacti.

Succulent plants, such as this Aloe, store water in their fleshy leaves

In botany, succulent plants, also known as succulents or sometimes fat plants, are plants having

some

parts

that

are

more

than

normally

thickened

and

fleshy,

usually

to

retain

water

in

arid

climates or soil conditions. Succulent plants may store water in various structures, such as leaves

and

stems.

Some

definitions

also

include

roots,

so

that

geophytes

that

survive

unfavorable

periods

by

dying

back

to

underground

storage

organs

may

be

regarded

as

succulents.

In

horticultural use, the term

would

regard

as

succulents,

such

as

cacti.

Succulents

are

often

grown

as

ornamental

plants

because of their striking and unusual appearance.

Contents

[hide]

1 Definition

2 Appearance

3 Habitat

4 Evolution

5 Families and genera

6 See also

7 References

8 Bibliography

9 External links

Definition[edit]

There are a number of somewhat different definitions of the term succulent. One difference lies

in

whether

or

not

roots

are

included

in

the

parts

of

a

plant

which

make

it

a

succulent.

Some

authors include roots, as in the definition

more than usually fleshy by the development of water-storing tissue.

in

the

definition

plant

with

thick,

fleshy

and

swollen

stems

and/or

leaves,

adapted

to

dry

environments

–

plants

that

survive

unfavorable

seasons

as

a

resting

bud

on

an

underground

organ.[3]

These

underground organs, such as bulbs, corms and tubers, are often fleshy with water- storing tissues.

Thus if roots are included in the definition, many geophytes would be classed as succulents.

Plants adapted to living

in

dry environments are termed xerophytes; thus succulents are often

xerophytes. However, not all xerophytes are succulents, since there are other ways of adapting to

a shortage of water, e.g. by developing small leaves which may roll up or having leathery rather

than succulent leaves.[4] Nor are all succulents xerophytes, since plants like Crassulahelmsii are

both succulent and aquatic.[5]

Those

who

grow

succulents

as

a

hobby

use

the

term

in

a

different

way

to

botanists.

In

horticultural

use,

the

term

succulent

regularly

excludes

cacti.

For

example,

Jacobsen's

three

volume Handbook of Succulent Plants does not cover cacti,[6] and

title or part of the title of many books covering the cultivation of these plants.[7][8][9] However,

in botanical terminology, cacti are succulents.[1] Horticulturists may also exclude other groups of

plants,

e.g.

bromeliads.[10]

A

practical,

but

unscientific,

horticultural

definition

is

succulent

plant

is

any

desert

plant

that

a

succulent

plant

collector

wishes

to

grow

Such

plants

less

often

include

geophytes

(in

which

the

swollen

storage

organ

is

wholly

underground)

but

do

include

plants

with

a

caudex,[12]

which

is

a

swollen

above-ground

organ

at

soil

level,

formed

from a stem, a root or both.[3]

A further difficulty is that plants are not either succulent or non-succulent. In many genera and

families there is a continuous sequence from plants with thin leaves and normal stems to those

with

very

clearly

thickened

and

fleshy

leaves

or

stems,

so

that

deciding

what

is

a

succulent

is

often arbitrary. Different sources may classify the same plant differently.[13]

Appearance[edit]

A collection of succulent plants, including cacti

The storage of water often gives succulent plants a more swollen or fleshy appearance than other

plants, a characteristic known as succulence. In addition to succulence, succulent plants variously

have other water-saving features. These may include:

Crassulacean acid metabolism (CAM) to minimize water loss

absent, reduced, or cylindrical-to- spherical leaves

reduction in the number of stomata

stems as the main site of photosynthesis, rather than leaves

compact, reduced, cushion-like, columnar, or spherical growth form

ribs enabling rapid increases in plant volume and decreasing surface area exposed to the sun

waxy,

hairy,

or

spiny

outer

surface

to

create

a

humid

micro- habitat

around

the

plant,

which

reduces air movement near the surface of the plant, and thereby reduces water loss and creates

shade

roots

very

near

the

surface

of

the

soil,

so

they

are

able

to

take

up

moisture

from

very

small

showers or even from heavy dew

ability

to

remain

plump

and

full

of

water

even

with

high

internal

temperatures

(e.g.

52

°

C

or

126 °

F)[14]

very impervious outer cuticle (skin)[14]

mucilaginous substances, which retain water abundantly[14]

Habitat[edit]

Question

This section does not cite any references or sources. Please help improve this section by adding

citations to reliable sources. Unsourced material may be challenged and removed. (January 2013)

Many

succulents

come

from

the

dry

areas

such

as

steppes,

semi-desert,

and

desert.

High

temperatures

and

low

precipitation

force

plants

to

collect

and

store

water

to

survive

long

dry

periods. Succulents may occasionally occur as epiphytes -

contact with the ground, and are dependent on their ability to store water and gain nutrients by

other means; this niche is seen in Tillandsia. Succulents also occur as inhabitants of sea coasts

and

dry

lakes,

which are exposed

to

high

levels

of

dissolved

minerals

that

are

deadly

to

many

other plant species.

Evolution[edit]

Question

This section does not cite any references or sources. Please help improve this section by adding

citations to reliable sources. Unsourced material may be challenged and removed. (January 2013)

The best-known succulents are cacti (family: Cactaceae). Virtually all cacti are succulents, but not

all

succulents

are

cacti.

A

unique

feature

of

cacti

is

the

possession

of

areoles,

structures

from

which spines and flowers are produced.

To

differentiate

between

these

two

basic

types

that

seem

so

similar,

but

that

are

unrelated

succulent plants, use of the terms, cactus or cacti, only should be used to describe succulents in

the cactus family. Popular collection of these types of plants has led to many Old World plants

becoming established in the wild in the New World, and vice versa.

Families and genera[edit]

This section includes a list of references, related reading or external links, but the sources of this

section remain unclear because it lacks inline citations. Please improve this article by introducing

more precise citations. (September 2012)

Apocynaceae: Pachypodiumlealii, stem succulent

Xanthorrhoeaceae: Haworthiaarachnoidea, leaf succulent

Cactaceae: Rebutiamuscula, stem succulent

Crassulaceae: Crassulaovata, stem and leaf succulent

Euphorbiaceae: Euphorbia obesa ssp. symmetrica, stem succulent

Cylindropuntiaimbricata: stem, woody succulent

Malvaceae: Adansoniadigitata, stem succulent

Moringaceae: Moringaovalifolia, stem succulent

Asparagaceae: Beaucarnearecurvata, stem succulent

Asparagaceae: Dracaena draco, stem succulent

Euphorbia resinifera

Plant families and genera in which succulent species occur are listed below.

Order Alismatales

Araceae: Zamioculcas

Order Apiales

Apiaceae: Steganotaenia

Araliaceae: Cussonia

Order Asparagales

Amaryllidaceae (geophytes): Ammocharis, Apodolirion, Boophone, Brunsvigia, Crinum, Crossyne,

Cryptostephanus,

Cyrtanthus,

Gethyllis,

Habranthus,

Haemanthus,

Hessea,

Nerine,

Pancratium,

Rauhia, Scadoxus, Strumaria, Zephyranthes,

Asparagaceae

subfamilyAgavoideae: Agave, Beschorneria, Chlorophytum, Furcraea, Hesperaloe, Hesperoyucca,

Yucca

subfamilyAsparagoideae: Asparagus

subfamilyLomandroideae: Cordyline,

subfamilyNolinoideae:

Beaucarnea,

Calibanus,

Dasylirion,

Dracaena,

Nolina,

Sansevieria,

Eriospermum

subfamily

Scilloideae:

Albuca,

Bowiea,

Daubenya,

Dipcadi,

Drimia,

Drimiopsis,

Eucomis,

Hyacinthus,

Lachenalia,

Ledebouria,

Litanthus,

Massonia,

Merwilla,

Namophila,

Ornithogalum,

Pseudogaltonia, Pseudoprospero, Resnova, Schizobasis, Schizocarphus, Spetaea, Veltheimia

Doryanthaceae: Doryanthes

Hypoxidaceae (geophytes): Empodium, Hypoxis, Pauridia, Saniella, Spiloxene

Iridaceae

(geophytes):

Babiana,

Chasmanthe,

Crocosmia,

Devia,

Dierama,

Dietes,

Duthiastrum,

Ferraria,

Freesia,

Geissorhiza,

Gladiolus,

Hesperantha,

Ixia,

Lapeirousia,

Melasphaerula,

Micranthus,

Moraea,

Pillansia,

Radinosiphon,

Romulea,

Sparaxis,

Syringodea,

Thereianthus,

Tritonia, Tritoniopsis, Watsonia, Xenoscapa

Orchidaceae

(succulents)

Acampe,

Aerangis,

Ansellia,

Bolusiella,

Bulbophyllum,

Calanthe,

Cyrtorchis, Oberonia, Polystachya, Tridactyle, Vanilla

(succulent geophytes) Eulophia, Liparis, Oeceoclades

(geophytes)

Acroliphia,

Bartholina,

Bonatea,

Brachycorythis,

Brownleea,

Centrostigma,

Ceratandra, Corycium, Cynorkis, Didymoplexis, Disa, Disperis, Dracomonticola, Eulophia, Evotella,

Gastrodia,

Habernaria,

Holothrix,

Huttonaea,

Neobolusia,

Nervilia,

Plicosepalus,

Pachites,

Platycoryne

subfamilyEpidendroideaePhalaenopsis

Xanthorrhoeaceae

subfamilyAsphodeloideae: Aloe (succulents and succulent geophytes), Astroloba, × Astroworthia,

Bulbine

(succulent

geophytes,

succulents,

and

geophytes),

Bulbinella

(geophyte),

Chortolirion

(succulent geophytes), Gasteria, Haworthia, Trachyandra (succulent geophytes and succulents),

subfamilyXanothorrhoeoidae: Xanthorrhoea

Order Asterales