Plant Classification

Question 1

What is a species made up of?

Answer 1

It’s made up of the Genus and the specific Epithet. Eg Taxus (genus) Baccata (epithet)

Question 2

5 Reasons why use the botanical name rather than the common name?

Answer 2

It is unique
It is stable
Internationally understood 
Identification of new plants is easier with a logical classification system
Plant characteristics are described

Question 3

What is a Genus?

Answer 3

A genus is a subgroup of a family. It is a taxon made up of groups of species which have similar characteristics. Eg. Rosa

Question 4

Definition of a Species?

Answer 4

Species is the unique binomial name given to a plant. Species are sub groups of genera. Species are the final stage of classification, unless there is a variation. The binomial name is composed of two words - the Genus and the specific epithet.
Eg. Digitalis Purpurea

Question 5

What are naturally occurring variations called?

Answer 5

Sub species, varieties and forms.

Question 6

What are man made variations called?

Answer 6

Cultivars

Question 7

What are cultivars?

Answer 7

Cultivars are horticultural variations of a species rather than natural occurring variations. The cultivar only exists because the gardener has intervened in some way.

Question 8

4 Reasons why not to use the common name?

Answer 8

Some plants don’t have a common name.
One plant can have more than one common name.
Common plant names can mislead - eg. Spanish Moss is not from Spain and is not moss!
One common name can mean different plants in different countries.

Question 9

Angiosperms have 2 subgroups what are they?

Answer 9

Dicotyledons and Monocotyledons

Question 10

What is an Angiosperm?

Answer 10

A flowering plant - includes 300,000 species

Question 11

What is a Gymnosperm?

Answer 11

A conifer, Cycads and ginkos. (only need to know conifers). Small group of 1000 species.

Question 12

What are the differences between a Gymnosperm and an Angiosperm?

Answer 12

Gymnosperms are mainly evergreen.
Angiosperms are evergreen and deciduous.

Angiosperms seed is enclosed in an ovary. (inside fruit)
Gymnosperms seed is naked, not enclosed.

Gymnosperms life cycle - perennial woody trees & shrubs.
Angiosperms lifecycle very diverse - woody, herbaceous, perennial, biennial, annual.

Gymnosperms pollen is wind dispersed.
Angiosperms has diverse mechanism for pollen dispersal. insects, bats, birds & wind.

Gymnosperms reproductive structure is a cone.
Angiosperms reproductive structure is a flower.

Gymnosperms have scale/needle like leaves.
Angiosperms have broad flat leaves.

Gymnosperms non flowering.
Angiosperms flowering.

Gymnosperms only tracheids to transport water.
Angiosperms have xylem vessels and tracheids to transport water.

Gymnosperms source of world’s softwood.
Angiosperms source of world’s hardwood.

Question 13

What is a Variety?

Answer 13

A variety is different to the original species that occurs naturally, but not as different as a subspecies.

Question 14

What is a form or forma?

Answer 14

Form or forma is a plant that has minor differences compared to the original species which occurs naturally. Eg. colour.

Question 15

What is a Subspecies?

Answer 15

A subspecies is a distinct variant. It is very different to the parent species plant, almost a new species but we call it a subspecies.

Question 16

What is a hybrid?

Answer 16

A hybrid is a cross between 2 different species or 2 different genera.

Question 17

Characteristics of a Moncotyledon leaf?

Answer 17

Shape is strap like (long and narrow) with an entire margin.
Attached to the stem with sheath like structure.
Parallel venation.
Bifacial. Stomata on both sides.

Question 18

Characteristics of a Dicotyledons leaf?

Answer 18

Shape is broad with various outlines.  
May have lobed or serrated edge.
Attached to stem by a petiole.
Reticulate venation.
Stomata on under surface only.

Question 19

Characteristics of a Monocotyledons flower?

Answer 19

Flower part in multiple of 3

Sepals & petals look similar and are called tepals.

Question 20

Characteristics of a Dicotyledons flower?

Answer 20

Flower part in multiples of 4 or 5.
Petals and Sepals look different and are named as separate whorls of petals and sepals. Often green sepals or different colour.

Question 21

Characteristics of a Monocotyledons stem?

Answer 21

Stem vascular bundles scattered.
No secondary thickening.
A single stem - usually unbranched like grass/daffodil.

Question 22

Characteristics of a Dicotyledons stem?

Answer 22

Stem vascular bundles arranged in a ring.
Secondary thickening as vascular cambium is present.
Branched - trees, shrubs, herbaceous perennials.

Question 23

Characteristics of a Monocotyledons root?

Answer 23

Fibrous system - roots all the same thickness.
Pith present.
Multi lobed xylem tissue.
No secondary thickening.
Radicle withers and forms adventitious roots.

Question 24

Characteristics of a Dicotyledons root?

Answer 24

Tap root system. Thick first root, then side roots.
No pith.
Simple lobed xylem tissue. (4-7 lobes)
Secondary thickening due to vascular cambium.
Radicle develops into the tap root.

Question 25

Characteristics of a Monocotyledons seed?

Answer 25

Embryo has 1 cotyledons.
At maturity may contain food store called endosperm.
eg. Stipa gigantea, Zea mays, Lolium perenne, Narcissus ‘February Gold’.

Question 26

Characteristics of a Dicotyledons seed?

Answer 26

Embryo has 2 cotyledons.
At maturity in many the food store is in the cotyledons.
eg. Geranium ‘Rosanne’, Betula utilis subs. jacquemontii ‘moonbeam’.

Question 27

What are the 5 stages of life of a plant?

Answer 27

Seed, juvenile, adult/mature, senescence, death.

Question 28

What are the characteristics of the seed life cycle stage?

Answer 28

Plant is in it’s dormant stage.
Seed embryo will develop when optimum conditions for germination are provided.
Will use food stored in the seed.
Low respiration rate.
A way for plant to wait for favourable conditions for the next stage of growth thus increasing the chance of survival.

Question 29

What are the characteristics of the juvenile life cycle stage?

Answer 29

Starts immediately after germination.
Seedling stage.
Length of juvenile stage varies from plant to plant - months to 40 years for a tree.
Vegetative growth only. Rapid growth. No flowers.

Question 30

What are the characteristics of the Adult/mature life cycle stage?

Answer 30

Flowers, fruits and seeds are produced by sexual reproduction. Once this happens plant moves onto the next stage.

Question 31

What are the characteristics of the Senescence life cycle stage?

Answer 31

Senescence can apply to decline of the whole plant of just a plant organ. eg. Leaf fall in Autumn or ripening fruit.
Metabolic processes slow. Reproduction & growth cease,

Question 32

What are the characteristics of the death life cycle stage?

Answer 32

Respiration & photosynthesis stop.

Cell death and decay/decomposition.

Question 33

Give an example of a plant which has a long juvenile growth period?

Answer 33

Wisteria sinensis can stay in juvenile life cycle for up to 20 years! So buy a plant already in flower!

Question 34

How do we delay senescence?

Answer 34

By prolonging flowering - dead heading and harvesting, preventing the plant from putting it’s energy into seed production.
Herbaceous perennials can be lifted and divided every 3 years as they will show senescence in the centre and die.
Mow lawns regularly to stop flowering.

Question 35

What are the benefits of senescence?

Answer 35

Seeds are ready to collect or as a food crop.
Autumn leaf colour is attractive.
Leaf senescence can indicate time to harvest - potatoes.
Senescent seed heads can provide winter decoration in the ornamental gardens and a food source for wildlife.
Energy from senescent leaves can be stored in the bulb for next years flowers. (daffodil).
Senescent plant materials can be used to make compost.

Question 36

What is ephemeral?

Answer 36

A fleeting life cycle and has more than one lifecycle in one growing season. eg. Cardamine hirsuta (Hairy bittercress).

Question 37

An example of a semi evergreen plant?

Answer 37

It only loses it’s leaves in extreme winter conditions.

Ligustrum ovalifolium ‘Aureum’ - Golden privet.

Question 38

Definition of a hardy annual?

Answer 38

A plant that completes it’s lifecycle in 1 year. It can survive temperatures lower -5 degrees sometimes down to -20 degrees. They are sown direct in Autumn or March.

Question 39

Definition of a half hardy annual?

Answer 39

A plant that completes it’s life cycle in a year.
It can survive temperatures down to -5 degrees. It is sown under protection and then planted out when the danger of frost has passed.

Question 40

Definition of a Tender perennial?

Answer 40

A plant which lives for more than 2 years, but cannot tolerate cold temperatures so needs to be protected from frost. It is grown under protection when temperatures are below 1 degree. Often overwintered in a heated greenhouse.

Question 41

Give 5 examples of a Hardy Annual?

Answer 41

Lathyrus Odoratus
Calendula officinalis.
Helianthus annus.
Limnanthes Douglasii (poached egg plant)
Nigella Damascena  (love in the mist)
Cosmos Bipinnatus 'Purity'

Question 42

Give 5 examples of Half Hardy Annuals?

Answer 42

Lobelia erinus 'Sapphire'
Begonia semperflorens cultorum.
Petunia x hybrida 'black velvet'
Tagetes patula 'honeycomb'
Pelargonium 'red cascade' - treated as half hardy annual.