Plants in their proper places - Royal Horticultural Society

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Plants in their proper places - Royal Horticultural Society

Introduction

Most gardeners are familiar with the Latin names for

plants, even if they do not like using them. What

they may also notice on labels in public gardens, as

well as in the RHS Plant Finder, are the family

names, which end in -aceae. The family is the next

main rank above that of genus and is the means to

indicate that genera belonging to the same family

are more similar to each other than to those that

belong in another family. This is part of a botanical

hierarchy used to organise plants into an overall

system of relatedness, generally referred to as a

classification. Man has been classifying plants since

at least Theophrastus (c. 300bc) and our current

system dates back to Linnaeus (1753), who

introduced the concept of the binomial (genus and

species name) as well as the arrangement of plants

according to their flower structure. Both concepts

have dominated our thinking about how we name

and classify plants although, over time, we have been

able to find different ways of collecting information

about plants, and different kinds of data with which

to test our classifications. The most recent of these

techniques has been the analysis of genetic material

(genome) and this has been applied to plants as

much as it has to other kinds of organisms. The

results of analysing many thousands of different

plants have brought about a new understanding of

plant relationships and, consequently, a major

reclassification of plants, and flowering plants

(angiosperms) in particular.

The new classification is known by the acronym

APG (Angiosperm Phylogeny Group) which refers

to the international team of scientists that have been

carrying out the analysis of plant genetic material

over the past 15 to 20 years. There have been three

classifications published (APG, 1998, 2003 and

2009), generally known as APG, APG II and APG

III. While the work has been known about for some

time it is only really over the past five years that its

impact has begun to be felt more widely, with major

institutions such as the Royal Botanic Gardens, Kew

and Edinburgh adopting the APG system for their

herbaria and plant labelling. A recent Plant Network

conference (www.plantnetwork.org/proceeds/

wales2009/summary.htm) showed how the new system

is being taken up in public gardens in the UK

(Latta, 2008; Horticulture Week, 7 August 2009). In

view of this, the RHS’s Advisory Committee on

Nomenclature and Taxonomy took the decision that

it was appropriate for the RHS to adopt the

classification as presented in the latest edition of

Plants in their proper places

Plants in their proper places – the new

classification of flowering plants

Mabberley’s Plant-book (2008) for use in the RHS

horticultural database, from which the RHS Plant

Finder is produced as well as the labels for plants in

our gardens. This is broadly the same as the

classification presented in the latest version of the

APG classification (APG, 2009) and the differences

are shown in the table with this article.

7

The importance of classification

A classification is, in the most abstract sense, a

method of organising information. It has at least

two functions: to enable communication, as such

names are a shorthand to indicate relationships, and

to predict, in that in associating entities you should

be able to ascertain the properties of one entity from

its position in the classification. It should also be

possible to incorporate new information. For plants,

as for any other living organisms, that element of

predictiveness means that the basis for the

classification must be genetic relatedness (or shared

descent). Although Linnaeus’s most famous

classification, which is predictive, is not based on

relatedness, only shared characters, even Linnaeus

realised its artificiality and drew up a parallel system

based on what he thought was a more natural

arrangement. In the context of classification the

word natural is normally used to mean that it is

based on relatedness. Linnaeus, of course, classified

organisms over 100 years before Darwin published

his book On the Origin of Species by Means of

Natural Selection, which revolutionised the

theoretical basis of classification. It took a while for

the first classifications based on his theory of

evolution to be produced but ever since almost every

classification published represents the classifier’s

concept of evolutionary relationships.

The consequence of this is that every scientific

name we use conveys some information about the

plant’s relationships. The basic unit is the species,

and these are clustered together in genera so that

those that are most closely related belong in the

same genus, those more distantly related will belong

in other genera, which in turn are brought together

in families and so on, in a hierarchy that ultimately

reaches the level of Kingdom (such as Plantae, or

Plants). It is this premise of a plant’s relationships

being revealed through its name and classification

that is one source for name changes. As relationships

are better understood, so it is necessary to change

the position of the plant and this will generally lead

to a change in name. While this is so, it is also

widely accepted that such classifications are

PF_177195.indb 7 4/3/10 10:43:33


8

Plants in their proper places

hypotheses and that the categories in which we

arrange organisms are artificial constructs. In nature

there are no genera or families or orders: some argue

that species are real but as Linnaeus said, ‘nature

does not make leaps’, or to put it another way, when

you look at the individuals and populations that

make up plants that you are studying, it is often

hard to see where the divisions lie or whether those

divisions are there at all.

This explanation attempts to show why classifications

matter and, in particular, why the APG classification

and the changes it is making to plant labels and

information about plants matter to gardeners. By

and large the new classification does not affect the

genera – although these also are being changed by

the application of molecular methods – but does

make significant differences at the levels of family

and above. While molecular data have confirmed

many previously recognised relationships based on

morphological characters, what has been fascinating

is where families not previously thought to be close

together have been found to be closely related. This

has in many cases subsequently brought to light other

features such as plant chemistry and microscopic

characters, generally far less prone to rapid

evolutionary change than those features we have

traditionally relied on, like the flower, that support

the new classification. Molecular data have also

shown that our concepts of what are early evolving

plants and which have a more recent origin need to

change. This too affects the classification as early

evolving plants are customarily placed at the

beginning of a linear sequence of a classification,

while those that appeared later are at the end.

A survey of the new system

A long-standing fundamental division of flowering

plants is based on the number of seed leaves, and

the groups thus distinguished are known as

monocotyledons (one seed-leaf) and dicotyledons

(two seed-leaves). While the molecular data show

that the monocotyledons are a natural group, they

are found to have arisen from an ancestor with two

seed-leaves and so do not have a separate origin to

the dicots. It also shows that the earliest diverging

flowering plants are dicotyledonous in the

traditional sense of the word. It is of interest that

this relationship is borne out by the structure of the

pollen: the monocots and those dicots that arose

before the monocot-dicot divergence all have pollen

grains with either a single pore or single groove; the

later dicots (or eudicots) all have pollen grains based

on the three-pore or three-groove pattern.

The living flowering plant which diverged first

has been found to be a woody shrub (Amborella)

which is endemic to New Caledonia. While it had

always been regarded as being among the early

arising dicots, it had not been thought to be as

significant in flowering plant evolution as the

molecular data now indicate. It may be something of

a surprise that the water lilies are next in the sequence,

given the apparent complexity and conspicuousness

of their flowers. However, water lilies (Nymphaeaceae)

are beetle-pollinated and it has been observed that

many of the earliest flowering plants are beetlepollinated;

a reflection of the co-evolution of flowers

and many insect groups. It turns out that beetles are

amongst the earliest insect groups to evolve, and

that flower pollination, and thus flower structure,

has co-evolved with the insect pollinators, as insect

diversity increased rapidly alongside flowering plant

diversity. Also amongst the cluster of early diverging

angiosperms is another group of woody plants and

of these the best known to gardeners are Illicium

(allspice) and Schisandra in the family

Schisandraceae.

Next in the sequence and still before the divergence

of the monocots is a group of predominantly woody,

tropical plants characterised by Magnolia. Those

familiar with previous classifications will be aware

that Magnolia and its allies were thought to be the

earliest flowering plants to arise due to their relatively

unspecialised floral morphology. In addition to

Magnolia, also included in this group are Drimys

(Winteraceae), Aristolochia and Asarum (Aristolochiaceae),

Peperomia (Piperaceae), Chimonanthus (Calycanthaceae),

Laurus and Persea (Lauraceae) and the nutmeg (Myristica,

Myristacaceae).

It is after this point that the monocots and dicots

diverge and the remainder of the dicots are informally

referred to as the eudicots. It is amongst this group

that we start to see the differentiation of perianth

segments into petals and sepals, although this is not

universal and many eudicot flowers are much reduced

or adapted and have lost this feature. The first

eudicot group to arise is that which is represented by

the paradigm of flower morphology, Ranunculus.

Closely related are Berberis and Mahonia (Berberidaceae),

and the poppies (Papaveraceae, which also includes

Corydalis and Dicentra). It is the next group, however,

which probably causes one of the biggest surprises.

Associated together are three families of very different

appearance: another group of water lilies (Nelumbo),

the planes (Platanaceae) and the proteas (Proteaceae).

While there are no obvious features that all three

types of plant share, there are some characteristics

that link the planes and the proteas particularly, most

notably the stipules that surround the stem. Also

among the early diverging eudicots is the box family,

Buxaceae, which in previous classifications was

thought to be closer to the Euphorbiaceae.

This brings us to the group referred to as the

“core eudicots” amongst which the arrangement of

flower parts in fives is the basic plan, although as

with the differentiation of the perianth, there are

many variations in form where this basic plan is not

PF_177195.indb 8 4/3/10 10:43:34


evident. At the bottom of the core eudicots, sister to

all the rest is Gunnera (Gunneraceae), the flower

parts of which are still in twos. Next to the gunneras

comes a large group around the Saxifragaceae

which brings together families which had never

previously been associated, such as Cercidophyllum

(Cercidophyllaceae); Crassula (Crassulaceae); Ribes

(Grossulariaceae); Hamamelis and Corylopsis

(Hamamelidaceae); Itea (Iteaceae) and Paeonia

(Paeoniaceae). This highly diverse group appears to

have evolved rapidly towards the middle of the

Cretaceous and, as yet, no single uniting

characteristic has been identified.

At this point the eudicots divide into two major

lineages, the rosids and the asterids. Broadly this

reflects the organisation of the perianth into those

with separate petals and those where the petals are

fused, at least partially, into a tube. Earlier botanists

referred to these two groups as Polypetalae and

Gamopetalae respectively so it is fascinating to see

this reflected in the results from molecular analysis.

Amongst the rosids there are some more surprises:

the previously unsuspected relationship between the

euphorbias (Euphorbiaceae), the passion flowers

(Passifloraceae), the willows (Salicaceae), the violets

(Violaceae) and the tropical parasite with the largest

solitary flower, Rafflesia. Initially unexpected was the

revelation that the families related to the roses

(Rosaceae) are Cannabis (Cannabaceae), Elaeagnus

(Elaeagnaceae), the elms (Ulmaceae) and the nettles

(Urticaceae). The striking difference in appearance of

the flowers is largely due to wind pollination, which

favours reduced flowers with small petals or no

petals at all, a feature not unknown in the Rosaceae

(e.g. Sanguisorba, Polylepis).

While all these surprises might bring one to

question whether the molecular data are reliable as a

foundation for classification, or that errors may have

crept into the analysis, it should be pointed out that

this work has been carried out on many

representatives of each family and for up to six

different regions of the genome. Although there are

some discrepancies, and these are still the subject of

debate (leading to some plants still being “unplaced”

in the classification), most of the results are

consistent and therefore give confidence that these

are giving a more accurate picture of relationships.

Another cluster is the group of families which all

share the chemical feature of producing mustard

oils, distinctive for the pungent smell plants in these

families give off, especially if crushed. Although the

presence of mustard oils has been known for some

time, it was not until the molecular data showed

that the plants that produce these oils are related

that the significance of the oils for plant

classification was fully appreciated. This grouping

includes the cabbage family (Brassicaceae), the

capers (Capparaceae), the paw paws (Caricaceae),

Plants in their proper places

9

Cleome (Cleomaceae) and the nasturtiums

(Tropaeolaceae). Shared chemistry is also to be found

in the group of families related to the pinks

(Caryophyllaceae) which also includes the ice plants

(Aizoaceae), the cacti (Cactaceae), pokeweeds

(Phytolaccaceae) as well as spinach and beets

(Chenopodiaceae); to these have been added, on

molecular evidence, many of the families of

carnivorous plants (e.g. Droseraceae and

Nepenthaceae) as well as the sea heath

(Frankeniaceae) and tamarisk (Tamaricaceae).

In the other main lineage, the asterids, there

are two early diverging groups: one around the

Cornaceae which, unexpectedly, proves to be closer

to the Hydrangeaceae than indicated by floral

morphology; the other, a large cluster around the

Ericaceae which itself now includes the Epacridaceae,

Empetraceae and Pyrolaceae. This cluster contains

families long known to be related but also the phlox

family (Polemoniaceae) and the pitcher plants

(Sarraceniaceae). A contentious issue in APG I and

II has been the boundary between the Primulaceae

and the Myrsinaceae, the latter being largely tropical

shrubs and trees; however, under the current

classification these have been merged into one

family, Primulaceae.

It is amongst the core asterids that some major

families of horticulturally important plants are to

be found and one of the most keenly debated

questions has been the fate of the foxglove family

(Scrophulariaceae). Whereas in many cases the

molecular data have indicated that families might be

merged together, it is quite the reverse in the

Scrophulariaceae where some former members are,

according to APG II and III, placed in new or

different families, such as Calceolariaceae (Calceolaria),

Paulowniaceae (Paulownia) or Phrymaceae (Mimulus).

The greatest upheaval is, perhaps, the transfer of

many genera, such Antirrhinum, Digitalis and Hebe to

the Plantaginaceae, previously a small family of

predominantly wind-pollinated plants. What remains

in the Scrophulariaceae are a few of the original

genera, such as Verbascum and Phygelius, together

with others not originally thought to belong there

including Buddleja and Myoporum. While at first this

may seem an unlikely rearrangement, it should be

remembered that the Scrophulariaceae were never well

defined morphologically.

A similar situation arises with the systematics of

the honeysuckle family (Caprifoliaceae), which in an

earlier version was broken up into a number of

different families. In the latest treatment (APG III),

they have all been combined, together with the

teasel family (Dipsacaceae) and the valerians

(Valerianaceae), into one family, Caprifoliaceae, with

the exception of Sambucus and Viburnum. These

have been referred to the Adoxaceae, a family

originally of small herbaceous woodland plants.

PF_177195.indb 9 4/3/10 10:43:34


10 Plants in their proper places

Some may be surprised by the appearance of the

umbellifers (Apiaceae and the closely related family

Araliaceae) among the asterids alongside Pittosporum

and Griselinia. Also notable is Escallonia,

traditionally considered to be closely related to the

currants (Grossulariaceae) and broadly associated

with the roses, which now comes out as a distinctive

lineage among the asterids.

As mentioned above, the monocots have been

recognised as being a natural group, as defined by

the possession of one seed leaf, in the APG

classification, but changes to relationships within the

group have been proposed. The principal

horticultural groups are the aroids, the palms, the

grasses, bromeliads, gingers, orchids and the diverse

cluster of bulbous, cormous or rhizomatous

monocot plants. These latter have been treated in

many different ways, from a broadly circumscribed

Liliaceae to a large number of much smaller families

(Hyacinthaceae, Convallariaceae, etc.). Molecular

data have helped to resolve many of these

uncertainties and, as with the dicots, have pointed

out a number of more unexpected groupings.

The earliest diverging monocot lineage has been

found to be that leading to Acorus (sweet flag),

previously thought to be a member of the Araceae

(Arum family) and it is perhaps interesting to

observe that among the early diverging monocots,

the majority are aquatic. Other distinctive groups of

monocots such as the palms (Arecaceae) and the

gingers (Zingiberaceae) are still recognised, although

the pineapple family (Bromeliaceae) has been

revealed to be much more closely related to the

grasses (Poaceae) than previously thought.

Molecular data have helped greatly to improve

our understanding of the bulbous petaloid

monocotyledons and given greater significance to a

character, the nature of the seed coat, which had not

formerly been seen to be of importance. In this

group of plants there are two types of seed coat; one

type has a dark, non-cellular covering, the other has

a pale, cellular covering. This distinction neatly fits

with the molecular data, and consequently two main

groups are recognised: the asparagoids (Asparagales)

with dark-coated seeds, and the lilioids (Liliales)

with pale-coated seeds. The Liliaceae is now

circumscribed as a much smaller group of genera,

including Lilium, Tulipa, Fritillaria, Erythronium

and Tricyrtis; while Disporum, Uvularia and

Colchicum are now in the Colchicaceae.

The other main cluster, the asparagoids, includes

an unchanged Iridaceae and Amaryllidaceae, which

may be expanded to include Agapanthus and the

Alliaceae (onions). Many of the genera formerly

included in Liliaceae are now placed in an enlarged

Asparagaceae, such as Convallaria, Ornithogalum,

Scilla, Agave, Cordyline, Polygonatum and Ruscus.

Phormium and Hemerocallis come together in the

Hemerocallidaceae. The orchids, however, long held

to be an isolated group among the monocots, are

now shown to belong among the asparagoids,

reflecting the over-emphasis given in previous

classifications to conspicuous floral features of this

highly adapted group of plants.

Further research

As has been observed on a number of points in this

piece, the more startling rearrangements revealed by

molecular analysis often lack the shared characteristics

that would enable recognition by more traditional

means. The task now is to re-examine the many kinds

of data available to characterise plants to see which

one or ones fit the molecular data. These will vary

from group to group as evolution is driven by

different pressures over time. Further, there are still

uncertainties in the position of some groups, such as

the Boraginaceae, and these questions are still being

worked on, so further changes can be expected,

although these will be relatively minor. As this

research continues and new information comes to

light, these are incorporated in the Angiosperm

Phylogeny Website (www.mobot.org/MOBOT/

Research/APweb/welcome.html). This is an invaluable

resource for anyone interested in finding out more.

For those that prefer their information in print, the

standard reference is the third edition of Mabberley’s

Plant-book but the updated edition of Heywood et al.

(Flowering Plants of the World) is also based on APG,

although it diverges significantly in the treatment of

certain families.

Dr John David

RHS Chief Scientist

References

Angiosperm Phylogeny Group (1998). An Ordinal

Classification for the Families of Flowering Plants.

Annals of the Missouri Botanical Garden 85:

531–553.

Angiosperm Phylogeny Group (2003). An Update of

the Angiosperm Phylogeny Group Classification for

the Orders and Families of Flowering Plants: APG

II. Botanical Journal of the Linnean Society 141:

399–436.

Angiosperm Phylogeny Group (2009). An Update of

the Angiosperm Phylogeny Group Classification for

the Orders and Families of Flowering Plants: APG

III. Botanical Journal of the Linnean Society 161:

105–121.

Heywood, V.H., Brummitt, R.K., Culham, A. &

Seberg, O. (2007). Flowering Plant Families of the

World. Kew, RBG Kew.

Latta, J. (2008). Changing to APG II – Theory Put

into Practice. Sibbaldia 6: 133–153.

Mabberley, D.J. (2008). Mabberley’s Plant-book.

Third Edition. Cambridge, CUP.

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Plants in their proper places

Classification of a selection of plants found in UK

horticulture according to the arrangement in

Mabberley’s Plant-book, Ed. 3 (2008)

Only those families with one or more representative

genera in cultivation are given. Groups in square

brackets are ones for which there are no

representatives in UK horticulture.

Subclass Magnoliidae

[Superorder Amborellanae]

Superorder Nymphaeanae

Order Nymphaeales

Family Nymphaeaceae (Nymphaea)

Superorder Austrobaileyanae

Order Austrobaileyales

Family Schizandraceae (Schisandra, Illicium)

Order Chloranthales

Family Chloranthaceae (Chloranthus)

Superorder Magnolianae

Order Canellales

Family Winteraceae (Drimys, Pseudowintera)

Order Piperales

Family Aristolochiaceae (Aristolochia, Asarum)

Family Saururaceae (Saururus)

Order Magnoliales

Family Annonaceae (Asimina)

Family Magnoliaceae (Magnolia, Liriodendron)

Order Laurales

Family Atherospermataceae (Atherosperma,

Laurelia)

Family Calycanthaceae (Chimonanthus,

Calycanthus)

Family Lauraceae (Laurus, Lindera, Neolitsea,

Sassafras)

Monocots

Superorder Lilianae

Order Alismatales

Family Acoraceae 1 (Acorus)

Family Araceae (Arum, Dracunculus, Arisaema,

Zantedeschia, Lysichiton)

[Order Petrosaviales]

Order Dioscoreales

Family Dioscoreaceae (Dioscorea, Tacca)

Order Pandanales

Family Pandanaceae (Pandanus)

Order Liliales

Family Alstroemeriacae (Alstroemeria, Bomarea)

Family Colchicaceae (Colchicum, Disporum,

Uvularia, Gloriosa)

1 Treated as a separate order, Acorales in APG III

11

Family Liliaceae (Lilium, Erythronium,

Fritillaria, Tulipa)

Family Melanthiaceae (Veratrum, Paris, Trillium)

Family Philesiaceae (Philesia, Lapageria)

Family Smilacaceae (Smilax)

Order Asparagales

Family Amaryllidaceae (Amaryllis, Narcissus,

Galanthus, Sternbergia, Crinum)

Family Alliaceae 2 (Allium, Tulbaghia,

Nectaroscordum)

Family Agapanthaceae 2 (Agapanthus)

Family Asparagaceae (Agave, Hosta, Yucca,

Cordyline, Convallaria, Polygonatum, Ruscus,

Asparagus, Triteleia, Scilla, Hyacinthus,

Ornithogalum, Eucomis, Dianella)

Family Asteliaceae (Astelia)

Family Hypoxidaceae (Rhodohypoxis)

Family Iridaceae (Iris, Gladiolus, Moraea,

Sisyrinchium, Crocus, Watsonia, Crocosmia,

Dierama)

Family Ixoliriaceae (Ixolirion)

Family Orchidaceae (Bletilla, Cypripedium,

Dactylorhiza, Pleione, Dendrobium)

Family Tecophilaeaceae (Tecophilaea)

Family Hemerocallidaceae 3 (Hemerocallis,

Phormium)

Family Asphodelaceae 3 (Asphodeline,

Kniphofia, Eremurus, Aloe, Gasteria)

Family Xanthorrhoeaceae (Xanthorrhoea)

[Order Dasypogonales]

Order Arecales

Family Arecaceae (Palmae) (Trachycarpus,

Phoenix)

Order Poales

Family Bromeliaceae (Dyckia, Fascicularia,

Puya)

Family Cyperaceae (Cyperus)

Family Restionaceae (Thamnochortus, Elegia)

Family Poaceae (Poa, Miscanthus, Arundo,

Phyllostachys, Cortaderia, Stipa, Zea)

Order Commelinales

Family Commelinaceae (Tradescantia,

Commelina)

Family Pontederiaceae (Pontederia)

Family Haemadoraceae (Anigozanthus)

Order Zingiberales

Family Musaceae (Musa)

Family Strelitziaceae (Strelitzia)

2 Both families are included in Amaryllidaceae in APG III

3 Both families are included in Xanthorrhoeaceae in APG

III

PF_177195.indb 11 4/3/10 10:43:34


12 Plants in their proper places

Family Zingiberaceae (Cautleya, Hedychium,

Roscoea)

Family Cannaceae (Canna)

Eudicots

Superorder Ceratophyllanae

Order Ceratophyllales

Family Ceratophyllaceae (Ceratophyllum)

Superorder Ranunculanae

Order Ranunculales

Family Eupteleaceae (Euptelea)

Family Lardizabalaceae (Akebia, Decaisnea,

Holboellia)

Family Menispermaceae (Menispermum)

Family Berberidaceae (Berberis, Nandina,

Podophyllum, Epimedium)

Family Ranunculaceae (Clematis, Anemone,

Adonis, Delphinium, Aquilegia, Helleborus,

Glaucidium)

Family Papaveraceae (Papaver, Corydalis,

Romneya, Macleaya, Meconopsis, Dicentra)

Unplaced Order Sabiales 4

Family Sabiaceae (Meliosma)

Superorder Proteanae

Order Proteales

Family Proteaceae (Protea, Banksia, Grevillea,

Hakea, Telopea, Embothrium)

Family Platanaceae (Platanus)

Unplaced Order Trochodendrales 4

Family Trochodendraceae (Trochodendron,

Tetracentron)

Superorder Buxanae

Order Buxales

Family Buxaceae (Buxus, Sarcococca, Pachysandra)

Core Eudicots

Superorder Myrothamnanae

Order Gunnerales

Family Gunneraceae (Gunnera)

Superorder Berberidopsidanae

Order Berberidopsidales

Family Berberidopsidaceae (Berberidopsis,

Aextoxicon)

Unplaced order Dilleniales 5

Family Dilleniaceae (Hibbertia)

4 The position of these two orders with respect to the

Proteanae and Buxanae is still unresolved and hence they

are treated as “unplaced”

5 Order Dilleniales not recognised in APG III; the family is

left as “unplaced”

Superorder Caryophyllanae

Order Caryophyllales

Family Nepenthaceae (Nepenthes)

Family Droseraceae (Dionaea, Drosera)

Family Tamaricaceae (Tamarix)

Family Frankeniaceae (Frankenia)

Family Plumbaginaceae (Plumbago,

Ceratostigma, Armeria, Limonium)

Family Polygonaceae (Polygonum, Persicaria,

Rheum)

Family Caryophyllaceae (Dianthus, Lychnis,

Gypsophila)

Family Amaranthaceae (Amaranthus, Beta,

Chenopodium)

Family Portulacaceae (Portulaca, Lewisia,

Calandrinia)

Family Cactaceae (Opuntia, Cereus)

Family Aizoaceae (Carpobrotus, Delosperma,

Ruschia)

Family Phytolaccaceae (Phytolacca, Ercilla)

Family Nyctaginaceae (Mirabilis)

Superorder Santalanae

Order Santalales

Family Loranthaceae (Viscum)

Order Saxifragales 6

Family Cercidophyllaceae (Cercidophyllum)

Family Crassulaceae (Crassula, Kalanchoe,

Sedum, Sempervivum, Echeveria)

Family Daphniphyllaceae (Daphniphyllum)

Family Grossulariaceae (Ribes)

Family Haloragaceae (Haloragis)

Family Hamamelidaceae (Hamamelis, Parrotia,

Corylopsis, Liquidambar 7 )

Family Iteaceae (Itea)

Family Paeoniaceae (Paeonia)

Family Saxifragaceae (Saxifraga, Astilbe, Bergenia,

Darmera, Heuchera, Rodgersia, Tiarella)

Superorder Rosanae

Order Vitales

Family Vitaceae (Vitis, Parthenocissus)

Order Crossosomatales

Family Staphyleaceae (Staphylaea)

Family Stachyuraceae (Stachyurus)

Order Geraniales 8

Family Melianthaceae (Melianthus,

Greyia)

Family Francoaceae 9 (Francoa)

Family Geraniaceae (Geranium, Pelargonium,

Erodium)

Order Myrtales 8

6 Treated as “unplaced” in APG III, i.e. not assigned to a

Superorder

7 Recognised in APG III in the separate family Altingiaceae

8 APG III has these orders in the Malvids – Eurosids II

9 Included in Melianthaceae in APG III

PF_177195.indb 12 4/3/10 10:43:34


Family Lythraceae (Lythrum, Punica,

Lagerstroemia, Cuphea, Heimia)

Family Onagraceae (Fuchsia, Clarkia,

Oenothera, Gaura)

Family Myrtaceae (Myrtus, Eucalyptus,

Callistemon, Luma, Acca, Leptospermum)

Family Melastomataceae (Tibouchina,

Osbeckia, Heterocentron)

Fabids – Eurosids I

Order Zygophyllales

Family Zygophyllaceae (Peganum)

Order Celastrales

Family Celastraceae (Euonymus, Maytenus,

Parnassia)

Order Malpighiales

Family Salicaceae 10 (Salix, Azara, Idesia,

Poliothyrsis, Populus)

Family Violaceae (Viola, Melicytus)

Family Passifloraceae (Passiflora)

Family Euphorbiaceae (Euphorbia, Ricinus,

Codiaeum, Acalypha, Croton, Mallotus)

Family Hypericaceae (Hypericum)

Family Linaceae (Linum)

Order Oxalidales

Family Oxalidaceae (Oxalis, Biophytum)

Family Cunoniaceae (Eucryphia, Weinmannia)

Family Elaeocarpaceae (Crinodendron, Aristotelia)

Order Fabales

Family Quillajaceae (Quillaja)

Family Fabaceae (Acacia, Cercis, Gleditsia,

Caesalpinia, Sophora, Baptisia, Cytisus,

Genista, Lupinus, Indigofera, Wisteria,

Phaseolus, Robinia, Coronilla, Clianthus,

Trifolium, Lathyrus, Pisum)

Family Polygalaceae (Polygala)

Order Rosales

Family Rosaceae (Rosa, Potentilla, Geum,

Alchemilla, Acaena, Filipendula, Exochorda,

Spiraea, Kerria, Dryas, Rubus, Prunus,

Chaenomeles, Malus, Sorbus, Cotoneaster,

Pyracantha)

Family Elaeagnaceae (Elaeagnus, Hippophae)

Family Rhamnaceae (Rhamnus, Ceanothus,

Colletia)

Family Ulmaceae (Ulmus, Celtis, Zelkova)

Family Cannabaceae (Cannabis, Humulus)

Family Moraceae (Morus, Ficus, Broussonetia)

Family Urticaceae (Urtica, Boehmeria)

Order Cucurbitales

Family Corynocarpaceae (Corynocarpus)

Family Coriariaceae (Coriaria)

Family Cucurbitaceae (Cucumis, Cucurbita,

Bryonia, Ecballium, Citrullus)

Family Datiscaceae (Datisca)

10 Includes a number of genera formerly assigned to the

Flacourtiaceae

Plants in their proper places

13

Family Begoniaceae (Begonia)

Order Fagales

Family Nothofagaceae 11 (Nothofagus)

Family Fagaceae (Fagus, Quercus, Castanea,

Lithocarpus)

Family Myricaceae (Myrica, Morella, Comptonia)

Family Betulaceae (Corylus, Betula, Carpinus,

Alnus)

Family Casuarinaceae (Allocasuarina)

Family Juglandaceae (Juglans, Carya,

Pterocarya)

Malvids – Eurosids II

[Order Huerteales]

[Order Picramniales]

Order Brassicales

Family Tropaeolaceae (Tropaeolum)

Family Limnanthaceae (Limnanthes)

Family Resedaceae (Reseda)

Family Capparaceae (Capparis)

Family Cleomaceae (Cleome)

Family Brassicaceae (Brassica, Erysimum,

Aubrieta, Matthiola, Lunaria, Iberis,

Raphanus, Crambe)

Order Malvales

Family Malvaceae (Tilia, Lavatera,

Fremontodendron, Hoheria, Althaea, Alcea,

Hibiscus, Abutilon)

Family Thymelaeaceae (Daphne, Edgeworthia,

Wikstroemia)

Family Cistaceae (Cistus, Halimum,

Helianthemum)

Order Sapindales

Family Sapindaceae (Acer, Aesculus, Dodonaea,

Koelreuteria)

Family Simourabaceae (Ailanthus, Picrasma)

Family Anacardiaceae (Rhus, Cotinus, Schinus)

Family Rutaceae (Citrus, Choisya, Skimmia,

Phellodendron, Dictamnus, Ruta, Cneorum)

Superorder Asteranae

Order Cornales

Family Cornaceae (Cornus, Alangium)

Family Nyssaceae (Nyssa, Davidia)

Family Hydrangeaceae (Hydrangea, Deutzia,

Philadelphus, Carpenteria, Kirengashoma)

Family Loasaceae (Loasa, Mentzelia)

Order Ericales

Family Balsaminaceae (Impatiens)

Family Polemoniaceae (Phlox, Polemonium,

Cantua, Cobaea, Gilia)

Family Theaceae (Camellia, Stewartia)

Family Pentaphylacaceae (Cleyera, Eurya)

Family Ebenaceae (Diospyros)

Family Primulaceae (Primula, Cyclamen,

Dodecatheon, Lysimachia, Myrsine)

11 Previously included in the Fagaceae

PF_177195.indb 13 4/3/10 10:43:34


14 Plants in their proper places

Family Styracaceae (Styrax, Halesia,

Pterostyrax)

Family Diapensiaceae (Diapensia, Galax,

Shortia)

Family Actinidiaceae (Actinidia,

Clematoclethra, Saurauia)

Family Sarraceniaceae (Sarracenia)

Family Clethraceae (Clethra)

Family Ericaceae 12 (Erica, Calluna, Cassiope,

Kalmia, Rhododendron, Vaccinium, Pyrola,

Empetrum, Cyathodes, Richea)

Lamiids – Euasterids I

Family Boraginaceae 13 (Borago, Echium,

Nemophila, Anchusa, Lithodora, Omphalodes,

Pulmonaria, Phacelia)

Order Garryales

Family Eucommiaceae (Eucommia)

Family Garryaceae (Aucuba, Garrya)

Order Gentianales

Family Rubiaceae (Coprosma, Bouvardia,

Luculia, Asperula, Phuopsis)

Family Gentianaceae (Gentiana, Eustoma,

Exacum, Centaurium)

Family Apocynaceae 14 (Nerium,

Trachelospermum, Vinca, Asclepias, Hoya,

Dregea, Stapelia)

Order Solanales

Family Solanaceae (Solanum, Lycium,

Cestrum, Nicotiana, Datura, Petunia,

Salpiglossis)

Family Convolvulaceae (Convolvulus,

Ipomoea)

Order Lamiales

Family Oleaceae (Fraxinus, Jasminum, Olea,

Osmanthus, Syringa, Ligustrum)

Family Gesneriaceae (Haberlea, Ramonda,

Mitraria, Achimenes, Streptocarpus)

Family Calceolariaceae (Calceolaria, Jovellana)

Family Scrophulariaceae (Verbascum,

Phygelius, Diascia, Nemesia, Buddleja,

Myoporum)

Family Acanthaceae (Acanthus, Justicia,

Strobilanthes)

Family Verbenaceae (Aloysia, Verbena,

Rhaphithamnus)

Family Bignoniaceae (Catalpa, Eccremocarpus,

Campsis, Incarvillea)

Family Lamiaceae 15 (Lamium, Clerodendrum,

Vitex, Callicarpa, Caryopteris, Phlomis,

Salvia, Mentha, Thymus, Plectranthus,

Stachys)

12 Including Empetraceae and Epacridaceae

13 Family is “unplaced” (unassigned to an order) in both

Mabberley & APG III; also includes Hydrophyllaceae

14 Including Asclepiadaceae

15 Including some genera formerly in the Verbenaceae

Family Phrymaceae (Mimulus)

Family Paulowniaceae (Paulownia)

Family Orobanchaceae (Castilleja, Lathraea)

Family Plantaginaceae 16 (Digitalis,

Antirrhinum, Penstemon, Hebe, Rehmannia,

Bacopa)

Campanulids – Euasterids II

Desfontaniaceae 17 (Desfontania)

Escalloniaceae 18 (Escallonia)

Order Aquifoliales

Family Helwingiaceae (Helwingia)

Family Aquifoliaceae (Ilex)

Order Apiales

Family Griseliniaceae (Griselinia)

Family Araliaceae (Aralia, Schefflera,

Pseudopanax, Hedera, Hydrocotyle)

Family Apiaceae (Astrantia, Eryngium, Daucus,

Bupleurum, Angelica, Foeniculum)

Family Pittosporaceae (Billardieria,

Pittosporum)

Order Dipsacales

Family Adoxaceae (Adoxa, Viburnum,

Sambucus)

Family Caprifoliaceae 19 (Lonicera, Abelia,

Diervilla, Linnaea, Knautia, Scabiosa,

Valeriana, Centranthus, Morina)

Order Asterales

Family Rousseaceae (Carpodetus)

Family Campanulaceae 20 (Campanula,

Platycodon, Adenophora, Codonopsis,

Lobelia)

Family Argophyllaceae (Corokia)

Family Menyanthaceae (Menyanthes)

Family Goodeniaceae (Scaevola)

Family Asteraceae (Aster, Echinops,

Eupatorium, Centaurea, Senecio, Dahlia,

Helichrysum, Osteospermum, Bellis,

Erigeron, Chrysanthemum, Helianthus,

Mutisia, Olearia)

16 Including Globulariaceae

17 Treated as “unplaced” family by Mabberley, but included

in the Columelliaceae, in the order Bruniales (not

recognised by Mabberley) in APG III

18 Treated as “unplaced” family by Mabberley, but placed in

the order Escalloniales (not recognised by Mabberley) in

APG III

19 Including Dipsaceae, Valerianaceae and Morinaceae

20 Including Lobeliaceae

PF_177195.indb 14 4/3/10 10:43:34

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