Brassiceae . . . . Cabbage family ("Crucifers")

All Brassicaceae have 4 free petals, 4 free sepals, and (4-)6-stamens; identification is aided by having ripe fruits

A number of other genera, mostly casual, can occur (e.g. Alyssum, Berteroa, Bunias, Conringia, Erucastrum, Malcolmia, Microthlaspi, Neslia, Noccaea, Pachyphragma, Peltaria, Rapistrum, Turritis)

Key to Brassicaceae by flower colour:


Yellow-flowered spp. choose on LEAF SHAPE/TYPE:

Yellow flowers - Large, waxy leaves

Brassica rapa
Brassica napus
Brassica oleracea
Crambe maritima
Wild Turnip
Sea Kale
For other smaller waxy lvs see: Brassica; Thlaspi; Lepidium draba; Isatis (white vein);

Yellow flowers - Other entire(ish) leaves:

Aurinia saxatile
Camelina sativa
Erysimum cheiri
Diplotaxis tenuifolia
Golden Alison
Perennial Wall-rocket

Erysimum cheiranthoides
Isatis tinctoria
Sinapis arvensis
Brassica rapa
Treacle Mustard
Wild Turnip

Draba aizoides
Yellow Whitlowgrass

Yellow flowers - More or less deeply divided or pinnate leaves;

Diplotaxis muralis
Barbarea vulgaris
Barbarea intermedia
Coincya monensis
Annual Wall-rocket
Medium-flowered Winter-cress
Isle of Man cabbage

Sisymbrium officinale
Hirschfeldia incana
Brassica nigra
Sinapis alba
Hedge Mustard
Hoary Mustard
Black Mustard
White Mustard
Note difference between S. officinale and Hirschfeldia incana (Hoary Mustard) is the latter is densely hairy with larger flowers

Raphanus raphanistrum ssp maritimum
Rorippa sylvestris
Rorippa palustris
Brassica napus
Sea Radish
Creeping Yellow-cress
Marsh Yellow-cress
Note B. napus has rough lower leaves

Sisymbrium altissimum
Sisymbrium orientale
Sisymbrium irio
Diplotaxis tenuifolius
Tall Rocket
Eastern Rocket
London Rocket
Perennial Wall-rocket

Minute or greenish flowers

Lepidium coronopus
Lepidium didymum
Lesser Swinecress

White flowers:
separate either by Flower shape, Fruit shape or by leaf shape

Brassicaceae-white by Flower shape:

Flowers White/cream with clawed petals:

Brassicaceae-white-regular: by fruit shape

Long narrow fruits

Cardamine armara
Cardamine flexuosa
Cardamine hirsuta
Cardamine pratensis
Large Bitter-cress
Way Bitter-cress
Hairy Bitter-cress
Cuckoo Flower

Alliaria petiolata
Arabidopsis thaliana
Arabis hirsuta
Garlic Mustard
Thale Cress
Hoary Whitlowgrass
Hairy Rock-cress

Arabidopsis petraea
Eruca vesicaria
Nasturtium officinale
Nasturtium microphyllum
Northern Rock-cress (Hamar)
Garden Rocket
Narrow-fruited Water-cress

Hesperis matrionalis
Cardamine corymbosa
Diplotaxis erucoides
Cardamine heptaphylla
NZ Bitter-cress
White Wall-rocket
Pinnate Bitter-cress

Short, fat fruits

Cochlearia pyrenaica
Cochlearia micacea
Cochlearia danica
Cochlearia officinalis
Pyrenean Scurvygrass
Mountain Scurvygrass
Danish Scurvygrass
Common Scurvygrass

Cakile maritima
Raphanus raphanistrum ssp maritimum
Erophila verna
Armoracia rusticana
Sea Rocket
Sea Radish

Crambe maritima
Crambe maritima
Lepidium draba
Sea Kale
Sea kale

Lepidium coronopus
Lepidium didymum
Lobularia maritima
Hornungia petraea
Lesser Swine-cress
Sweet Alison

Broad flat fruits

Capsella bursa-pastoris
Thlaspi arvense
Lepidium heterophyllum
Lepidium sativum
Field Penny-cress
Smith's Pepperwort
Garden Cress

Lepidium campestre
Draba incana
Draba norvegica
Field Pepperwort
Caucasian Penny-cress
Hoary Whitlowgrass
Rock Whitlowgrass

Teesdalia nudicaulis
Hornungia petraea
Lepidium draba
Lunaria annua
Hoary Cress

See also: Candytuft

White Brassicaceae: separated by leaf shape:

Large leaves:

Pinnate or pinnately lobed leaves: (NB stem leaves sometimes entire)

Kidney or ivy-leaved:

Lobed, to toothed, to entire:



Sea Rocket

Matthiola sinuata
Matthiola incana
Matthiola longipetala
Sea stock
Night-scented Stock

Lunaria annua
Aubretia deltoidea
Sweet Alison

Alliaria . . . Garlic Mustard

Alliaria petiolata . . . Garlic Mustard

A common weed of rough ground

Arabidopsis . . . Thale Cress

Some fruits at least 45 degree from stem (c.f. Arabis)

Arabidopsis thaliana . . . Thale Cress

A common short-lived weed

Arabidopsis petraea (previously Arabis petraea. . . . Northern Rock-cress

A local mountain plant of Sc, rare in N Wa

Arabis . . . Rock-cress

Arabis hirsuta . . . Hairy Rock-cress

Locally frequent across BI; fruits long and erect

Alpine Rock-cress (A. alpina) is a rare plant of mountains in Skye; Bristol Rock-cress (A. scabra) is a rare plant of limestone nr. Bristol; [also Tower Cress (Pseudoturritis turrita) rare on old walls in Cambridge]

Armoracia . . . Horseradish

Armoracia rusticana . . . Horse-radish

Commonly naturalised on waste ground/grassy places in CI and En but less common in Wa, Sc and Ire

Divided leaf sports can occur:

Aubretia . . . . Aubretia

Aubretia deltoidea . . . . Aubretia

A garden-escape

Aurinia . . . Golden Alison

Aurinia saxatile . . . Golden Alison

A garden-escape - similar to another garden escape (Alyssum montanum) but has persistent basal leaves and flat hairless fruits; frequent around London and NE En, scattered elsewhere

Barbarea . . . Winter-cress

Stem leaves pinnate; fruits long & thin with obvious midrib

Barbarea intermedia . . . Intermediate-flowered Winter-cress

Scattered on waste and cultivated ground

American Winter-cress (B. verna) is similar but with fruits >4 cm, and petals > 5.6 mm, scattered in BI, decreasing to N

Barbarea vulgaris . . . Winter-cress

Throughout BI, exc. NW Sc, often in damp places; Stem leaves largely ovate, toothed

Small-flowered Winter-cress (B. stricta) is similar, style on fruit <2mm, sepal tips hairy, scattered esp. in C En and Wa

See also: Rorippa

Brassica . . . . . Cabbage

Brassica napus . . . Rape and Swede

Several subspp. cultivated including Oil-seed rape (ssp. oleifera) which is a common escape on roadsides, and Swede (ssp. rapifera).
Similar to B. rapa, but buds just overtopping open flowers; stem lvs clasping stem; petals >11 mm

Brassica nigra . . . Black Mustard

Tall plant, often 2m+; fruits closely pressed to stem; lower part of plant bristly not hairy, leaf stalks often purple; frequent in Br N to Yorkshire, scattered in Ire and Sc

Brassica oleracea . . . Cabbage

Scattered, mostly around the coasts on cliffs etc., and as casual on tips; rare in Ire and W Sc

Brassica rapa . . . Wild Turnip

Similar to B. napus, but buds below open fls, petals <12mm, lower lvs dark green and hairy; throughout BI as relic

Other casual spp. include:
Pale Cabbage (B. tournefortii); Ethiopian Rape (B. carinata); Chinese Mustard (B. juncea); and Long-stalked Rape(B. elongata)

Cakile . . . Sea Rocket

Cakile maritima . . . . . . Sea Rocket

Common on beaches

Camelina . . . Gold-of-pleasure

Camelina sativa . . . . . Gold-of-pleasure

Scattered mostly in arable fields from CI N to C Sc

Lesser Gold-of-pleasure (C. microcarpa) is less common, hairy and with smaller fls (petals to 4.6mm), style nearly as long as fruit

Capsella . . . . . Shepherd's-purse

Capsella bursa-pastoris . . . Shepherd's-purse

Common weed with characteristic heart-shaped fruit, note the v. different upper and lower leaves

A pink variant (C. rubella) is local around Southampton

Cardamine . . . . . Bitter-cress

Choose from the different Cardamine spp. below:

Cardamine armara . . . Large Bitter-cress

Wet places esp. in En and Sc; purple anthers

Cardamine bulbifera . . . . Coralroot

Pink or white fls, bulbils in leaf axils; rare as a native in woodland in SE En, but scattered as garden relict or escape (Pic.1 from Janet John)

Cardamine corymbosa . . . . New Zealand Bitter-cress

Scattered as garden escape throughout UK, somewhat invasive in nurseries

Cardamine heptaphylla . . . . Pinnate Bitter-cress

Scattered as naturalised garden escape/relict

Cardamine pratensis . . . Cuckooflower; Lady's-smock

Common in wet grassy places; upper lvs small with narrow lflets

Double version
See also:
(with broad leaflets)

Cardamine flexuosa . . . Wavy Bitter-cress

Like C. hirsuta, but has 6-stamens and 'kinked' stem, both spp. can be sparsely hairy; common esp. by streams

Cardamine hirsuta . . . Hairy Bitter-cress

Like C. flexuosa, but 4 stamens, hairy leaves and fruits and ungrooved stems; common garden weed but widely distributed

Cardamine raphanifolia . . . Broad-leaved Cuckooflower; Greater Cuckooflower

All lvs broad with terminal one large and round; close to, or in, streams, scattered through UK, darker than C. pratensis

See also Cuckooflower

which has narrow, not broad, lflets on stem

Other less common spp. include:
Narrow-lvd Bitter-cress (C. impatiens) stem lvs clasping stem, locally frequent Welsh borders, Manchester and NW

Cochlearia . . . Scurvygrass

The various spp. are rather difficult to separate - select from 4 spp. shown, or:
C. anglica - Basal leaves with tapering bases (not kidney-shaped), fruits laterally compressed
C. danica - Almost all leaves with petioles; ivy-leaf shaped; flowers <5mm
C. officinalis - Upper leaves clasping stem; flowers 8-15 mm
C. pyrenaica - Mountain plant, upper leaves hardly clasping stem; flowers 5-8 mm (C. micacea - Mountain plant with +/- woody base on micaceous schists; fruits pointed at ea. end; stem leaves stalked below; possibly just part of the C. pyrenaica complex)

Cochlearia danica . . . Danish Scurvygrass

By coasts; the species most commonly found along motorways

Cochlearia officinalis agg. . . . Common Scurvygrass

Common, upper lvs clasping stem

Others within this agg. include:

Cochlearia micacea . . . Scottish Scurvygrass

Rare mountain plant of Scottish micaceous schists (possiblysubsp. of C. officinalis)

Cochlearia pyrenaica . . . Pyranean Scurvygrass

Mountain plant (poss. subsp. C. officinalis)

Coincya . . . Isle of Man Cabbage/Wallflower Cabbage/Lundy Cabbage

Coincya monensis . . . Isle of Man Cabbage

Three subspp. recognised; local and restricted to CI, Man and W coasts of Br

Crambe . . . Sea kale

Crambe maritima . . . . . Sea Kale

A large coarse plant, mainly around the coasts S from Glasgow to E Anglia and S Ire

Descurainia . . . Flixweed

Descurainia sophia . . . Flixweed

Roadsides and waste places, most common in E

Diplotaxis . . . Annual Wall-rocket

Leaves have strong, nasty smell

Diplotaxis erucoides . . . White Wall-rocket

An occasional casual esp. around the Wash

Diplotaxis muralis . . . Annual Wall-rocket

CI N to C Sc, scattered elsewhere

Diplotaxis tenuifolia . . . Perennial Wall-rocket

Similar distribution to D. muralis, but esp. concentrated in CI and around S Wa, London and Newcastle

Draba . . . . . Whitlowgrass

Draba aizoides . . . . . Yellow Whitlowgrass

A European alpine thatis rare on limestone on the Gower in S Wa

Draba norvegica . . . . . Rock Whitlowgrass

Very local near Scottish mountain tops; has mostly simple hairs (cf. Draba incana which has many stellate hairs)

Erophila . . . . . Whitlowgrass

Erophila verna . . . . . Whitlowgrass

As with other Brassicaceae has 4 petals, but these are deeply divided; fruits c. equally long as broad; flowers very early in year; often tiny (<2 cm tall)

The densely hairy, Hairy Whitlowgrass (E. majuscula) is v. local and scattered across esp. S BI; Glabrous Whitlowgrass (E. glabrescens) is scattered in BI with less bifid petals and petioles longer than lf blades

Can be confused with Mouse-ears (esp. Cerastium diffusum):

Erysimum . . . . . Wallflowers

Erysimum cheiranthoides . . . Treacle Mustard

Local, but more common in C & S En

Erysimum cheiri . . . Wallflower

Scattered on walls and banks throughout most of BI

Erysimum x marahallii . . . . Siberian Wallflower

Scattered as garden escape on tips, etc., similar to wallflower but with orange flowers and fruits square in section

Eruca . . . . . Garden rocket

Eruca vesicaria . . . . . Garden Rocket

Hesperis . . . . . Dame's-violet

Hesperis matronalis . . . . . Dame's-violet

Widespread and commonly naturalised in waste places, hedgerows, etc

Hirschfeldia . . . . . Hoary Mustard

Hirschfeldia incana . . . Hoary Mustard

Fruits closely pressed to stem; one seed in beak of fruit; lower part of plant very hairy

Hornungia . . . Hutchinsia

Hornungia petraea . . . Hutchinsia

Tiny & v. early flowering (e.g. Mar), very local in dry calcareous places, CI, N & SW En, N Wa

Iberis . . . Candytuft

Iberis amara . . . Candytuft

On dry chalky soils: note the very asymmetric flowers (cf. Lobularia ); the wild sp. is annual; perennials (garden plants) are probably I. sempervirens.

Isatis . . . Woad

Isatis tinctoria . . . Woad

Mostly an infrequent casual

Lepidium . . . . Pepperworts and Swinecress

Lepidium campestre . . . . . Field Pepperwort

Style not exceeding notch of fr; scattered in Br on waysides and arable fields (Photo1 A.Haden)

Lepidium coronopus . . . . . Swinecress

Common in S BI, rare to N

Key difference from L. didymum is fruits with strong ridges and pits and tapered into a style

Lepidium didymum . . . . . Lesser Swinecress

Similar distribution to above, but extending further N

Key difference from L. coronopus is fruits which are rounded (not ridged) and notched above as well as below

Lepidium draba . . . . . Hoary Cress

Common in S BI, less so to N

Lepidium heterophyllum . . . . . Smith's Pepperwort

Common and widely distributed but uncommon in E En and W Ire

A similar species - L. campestre - has style not extending from notch in fruit and usually single stems

Lepidium sativum . . . . . Garden Cress

On tips and waysides across BI

Other spp. include:
Field Pepperwort (L. campestre); Narrow-lvd Pepperwort(L. ruderale): Dittander L. latifolium); and a substantial number of wool and birdseed aliens

See also:
Thlaspi and Teesdalia

Lobularia . . . Alison

Lobularia maritima . . . . . Sweet Alison

Commonly naturalised on walls, dry places and coasts

Lunaria . . . . . Honesty

Lunaria annua . . . . . Honesty

Common exc. NW Sc and W Ire

Matthiola . . . Stock

Matthiola incana . . . . . Stock

A garden escape on walls and banks

Matthiola longipetala . . . . . Night-scented Stock

Characteristic 'horned' fruits; a casual across Br on tips and from 'wildflower' mixes

Matthiola sinuata . . . . . Sea Stock

Very local on sand dunes and cliffs in S Ire, S Wa, S En and CI

Nasturtium . . . . . Watercress

Nasturtium officinale . . . Water-cress

Straight fruits (11-19 mm) with 2-rows of seeds and pedicels 7-12 mm; common in streams and ditches

Nasturtium microphyllum . . . . . Narrow-fruited Water-cress

Long, upward curving seed pods (16-25mm) with 1-row of seeds in each valve and pedicels 14-20 mm; similar places to N. officinale, but less common in S but more common in N

Pachyphragma . . . Stock

Pachyphragma giganteum . . . . . Caucasian Penny-cres

An uncommon garden escape scattered in woodland from Somerset N to Fife

Raphanus . . . Radish

Raphanus raphanistrum ssp. maritimum . . . . . Sea Radish

Yellow (rarely white) flowers; Note deep constrictions between the usually 2 to 3 seeds in pod (cf R. sativus); common around the coasts exc. for N&E Sc and E En

Raphanus raphanistrum ssp. raphanistrum . . . . . Wild Radish

Pink or white flowers; common

Raphanus sativus . . . . . Garden Radish

Pink or white flowers; Note inflated pod without constrictions between seeds

Rorippa . . . . . Yellow-cress

Flowers small with petals <6mm; fruits long & thin without obvious midrib

Rorippa palustris . . . . . Marsh Yellow-cress

Petals = sepals; In damp or wet places but rare in N Sc

Rorippa sylvestris . . . . . Creeping Yellow-cress

petals 1.5x sepals; in damp places but rare in N Sc

N.B. several other spp. can be found and include R. amphibia (like R. sylvestris but upper leaves only toothed not lobed), R. austriaca (fruit rounded) and R. islandica (like R. palustris but petals smaller at <1.6 mm)

See also: Barbarea

Sinapis . . . . . Mustard

Sinapis alba . . . . . White Mustard

All leaves pinnately lobed; beak of fruit flat (see pic. 2), longer than seeded part; widespread but less common in NW and most of Ire

Sinapis arvensis . . . . . Charlock

Common on roadsides, and arable land; bristly lvs and fruits, with upper leaves simple; the beak (tip) of fruit is not flattened and is shorter than the seeded part of fruit

Sisymbrium . . . Rockets

Sisymbrium altissimum . . . . Tall Rocket

Casual scattered in waste places; upper lvs include some finely pinnate

Sisymbrium irio . . . . London Rocket

Fruits overtop small fls; rare casual in waste places in En

Sisymbrium officinale . . . Hedge Mustard

Fruits pressed close to stem and flowers small (c.3 mm); common in waste places and cultivated land thoughout Br exc. N Sc

Sisymbrium orientale . . . Eastern Rocket

Casual scattered in waste places; upper lvs with only small lobes

A number of other relatively uncommon spp. can be found e.g. Perennial Rocket (S. strictissimum), a perennial with lvs hairy on lower side and long fruits, London Rocket (S. irio) with narrow pedicels and fls <5mm, False London-rocket (S. loeselii) an annual with regularly lobed lower lvs and fruits >3 cm, and French Rocket (S. erysimoides)

Subularia . . . Awlwort

Subularia aquatica . . . . . Awlwort

Tiny water plant (photos from '' and 'bonnier floraelectronica'); uncommon at the edge of lakes in NW Sc, also NW of En, Wa and Ire

See other water plants such as:
Lobelia Isoetes Littorella Juncus

Teesdalia . . . Teesdalia

Flowers slightly asymmetric with outer petals larger

Teesdalia nudicaulis . . . . . Teesdalia

Rare in Ire, but can be common elsewhere

Thlaspi . . . . . Field Penny-cress

Thlaspi arvense . . . . . Field Penny-cress

Common exc. NW SC and N Ire

See also: Lepidium spp.: