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The families of flowering plants

L. Watson and M.J. Dallwitz

Cruciferae Juss.

Alternatively Brassicaceae Burnett (nom. altern.).

Including Raphanaceae Horan., Stanleae (Stanleyaceae) Nutt.

Habit and leaf form. Herbs (mostly), or shrubs (rarely), or lianas (rarely). ‘Normal’ plants (mostly), or switch-plants (e.g. Caulanthus, sometimes spiny, e.g. Vella). Plants non-succulent (mainly), or succulent (a few, e.g. Cakile). Annual, biennial, and perennial; with a basal aggregation of leaves, or without conspicuous aggregations of leaves. Self supporting (usually), or climbing (rarely). When shrubby, often pachycaul. Hydrophytic, helophytic, mesophytic, and xerophytic; when hydrophytic, rooted. Leaves of hydrophytes submerged and emergent. Heterophyllous, or not heterophyllous. Leaves minute to very large; alternate; spiral (usually), or distichous (rarely); fleshy (occasionally), or ‘herbaceous’; petiolate, or subsessile, or sessile; sheathing to non-sheathing; foetid (sometimes), or without marked odour; simple (usually), or compound (rarely); epulvinate; when compound, pinnate (with articulated leaflets). Lamina when simple, dissected to entire; when simple-dissected, pinnatifid, or runcinate; one-veined (rarely), or pinnately veined; cross-venulate. Leaves exstipulate. Lamina margins entire, or serrate, or dentate. Leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral, or bifacial, or centric. Mucilaginous epidermis present (commonly), or absent. Hairs of numerous kinds present (in the family; mostly unicellular but these variously simple, forked, Y- or T- shaped, sometimes stellate: see illustration); eglandular (mostly), or glandular (found in only a few genera, e.g Hesperis, Matthiola). Minor leaf veins without phloem transfer cells (4 genera).

Axial (stem, wood) anatomy. Young stems with solid internodes, or with hollow internodes (commonly). Pith mostly without diaphragms; mostly homogeneous. Cork cambium present (at least in woody forms), or absent; when present, initially deep-seated. Nodes unilacunar, or tri-lacunar, or multilacunar. Primary vascular tissues variously in a cylinder, without separate bundles (with a continuous ring of cambium, and recognisable medullary rays much reduced or absent), or comprising a ring of bundles (with or without subsequent interfascicular cambial activity); collateral. Cortical bundles present (rarely), or absent. Medullary bundles present (rarely), or absent. Secondary thickening absent, or developing from a conventional cambial ring (the lignified interfascicular tissue usually lacking vessels), or anomalous (occasionally). The anomalous secondary thickening when present via concentric cambia, or from a single cambial ring.

The vessels solitary, or solitary, in radial multiples, and clustered. The vessel end-walls simple. The vessels with vestured pits. The axial xylem with fibre tracheids; without septate fibres. The fibres without spiral thickening. The parenchyma paratracheal (scarce). ‘Included’ phloem present (e.g.Brassica, Cochlearia), or absent. The wood partially storied, or not storied (?).

Reproductive type, pollination. Plants hermaphrodite. Floral nectaries present (nearly always), or absent. Nectar secretion from the perianth, from the disk, and from the androecium. Pollination anemophilous (e.g.Pringlea), or entomophilous (mostly).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’ (usually), or solitary (rarely); in corymbs (commonly), or in racemes, or in spikes, or in fascicles. The ultimate inflorescence units racemose. Inflorescences terminal, or axillary, or leaf-opposed (e.g. Coronopus); sometimes more or less pseudanthial, or not pseudanthial. Flowers ebracteate (usually), or bracteate; ebracteolate (mostly), or bracteolate; minute to medium-sized; fragrant, or odourless; more or less regular (usually), or somewhat irregular. The floral irregularity (when noticeable) involving the perianth (the outer petals of pseudanthia sometimes radiate and larger). Flowers 2 merous; cyclic; polycyclic (usually 6), or tetracyclic to pentacyclic (when C or A whorls lacking). Floral receptacle nearly always with neither androphore nor gynophore (by contrast with Capparidaceae — the long, slender gynophore of Stanleyeae being exceptional). Free hypanthium absent. Hypogynous disk present (nearly always), or absent; extrastaminal, or intrastaminal, or extrastaminal and intrastaminal (usually between and/or external to the filaments, sometimes surrounding their bases); of separate members (usually, in variable configurations which are of taxonomic interest), or annular (in that the members are sometimes confluent).

Perianth with distinct calyx and corolla, or sepaline (the corolla occasionally lacking); 8 (usually), or 4; characteristically 3 whorled (K 2+2 decussate with the outer pair median, C4, the corolla diagonal), or 2 whorled (when corolla lacking). Calyx 2 whorled (generally, supposedly — usually obviously so in bud); polysepalous; regular; members sometimes dimorphic, with the lateral (inner) pair often basally saccate for nectar storage; decussate. Corolla 4 (diagonal); 1 whorled; polypetalous; imbricate, or contorted; regular (usually); white, or yellow, or orange, or purple, or blue. Petals clawed (usually), or sessile (e.g. Cuphonotus, Geococcus).

Androecium 6 (usually), or 2–4, or 8–16 (rarely). Androecial members branched (usually, in that the inner whorl of 4 is derived from only 2 primordia), or unbranched; free of the perianth; markedly unequal (usually, the outer pair shorter), or all equal; free of one another, or coherent (the inner four sometimes basally connate in pairs); 2 whorled (usually, 2+4), or 1 whorled. Androecium exclusively of fertile stamens. Stamens 6 (usually), or 2–4, or 8–16 (rarely); tetradynamous (nearly always), or not didynamous, not tetradynamous (when the outer pair missing); oppositisepalous. Filaments appendiculate, or not appendiculate. Anthers basifixed; non-versatile; dehiscing via longitudinal slits; introrse; unilocular to bilocular; tetrasporangiate; variously appendaged, or unappendaged. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral, or isobilateral, or decussate. Anther wall initially with one middle layer, or initially with more than one middle layer; of the ‘monocot’ type. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate, or nonaperturate (occasionally); 3(–10) aperturate; colpate; 3-celled (in 16 genera).

Gynoecium 2 carpelled. The pistil 1–2 celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary 1–2 locular. Locules secondarily divided by ‘false septa’ (usually, as evidenced by the longitudinal splitting of the parietal placentas by the replum), or without ‘false septa’ (e.g. Menkea). Gynoecium transverse. Ovary sessile (usually), or stipitate (rarely, cf. Capparidaceae). Gynoecium non-stylate, or non-stylate to stylate. Styles 1 (more or less reduced); apical. Stigmas 1–2; commissural (mostly, when detectably two or bilobed), or dorsal to the carpels (e.g. Matthiola, Moricandia); 1 lobed, or 2 lobed; more or less capitate; dry type; papillate; Group II type. Placentation when unilocular, parietal; when bilocular, parietal (but peculiarly so, the usual two placentas usually each longitudinally divided by a ‘false’ septum, the ‘replum’, separating the locules). Ovules in the single cavity 1–50 (to ‘many’); (1–)3–50 per locule (i.e. usually several to ‘many’ per placenta); commonly pendulous, or horizontal; with ventral raphe; non-arillate; anatropous; bitegmic; tenuinucellate, or crassinucellate. Outer integument contributing to the micropyle. Embryo-sac development Polygonum-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked (sometimes with filiform apparatus). Endosperm formation nuclear. Embryogeny onagrad.

Fruit non-fleshy; dehiscent (usually), or indehiscent (Cakile, Crambe, Coronopus etc), or a schizocarp (e.g. sometimes in Coronopus), or lomentaceous (or sometimes partially so). Mericarps when schizocarpic, 2. Fruit a silicula to a siliqua (with variations on these themes, sometimes partially of entirely lomentaceous), or capsular-indehiscent (i.e. when neither dehiscent nor lomentaceous). Capsules when dehiscent, valvular (the valves usually falling or spreading upwards to reveal the replum). Seeds scantily endospermic, or non-endospermic; small to medium sized; winged (e.g. Matthiola, Isatis), or wingless. Embryo well differentiated. Cotyledons 2; flat, or folded (longitudinally or transversely). Embryo chlorophyllous (32/52); bent (nearly always folded, cotyledons against radicle), or straight (e.g. Leavenworthia). The radicle lateral, or dorsal.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3 (almost exclusively), or C3-C4 intermediate. C3 physiology recorded directly in Barbarea, Berteroa, Brassica, Cakile, Capsella, Cheiranthus, Crambe, Dipterygium, Farsetia, Matthiola, Raphanus, Sisymbrium, Thlaspi. C3-C4 intermediacy in Moricandia (3 species). Anatomy non-C4 type (Aethionema, Alyssum, Arabis, Brassica, Capsella, Cardamine, Descurainia, Diceratella, Draba, Erysimum, Erucastrum, Farsetia, Fortuynia, Leavenworthia, Lepidium, Lesquerella, Matthiola, Morieria, Oreophyton, Rorippa, Sisymbrium, Thlaspi etc.). Mustard-oils present. Cyanogenic, or not cyanogenic. Alkaloids present, or absent (more often). Arbutin absent. Iridoids not detected. Proanthocyanidins absent (except sometimes in the seedcoat). Flavonols present, or absent; when present, kaempferol and quercetin. Ellagic acid absent (9 species, 7 genera). Aluminium accumulation not found. Sieve-tube plastids P-type, or S-type; when P-type type I (b).

Geography, cytology. Frigid zone to tropical. Cosmopolitan, concentrated in the North temperate and Mediterranean. X = 5–12(+).

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Violiflorae; Capparales. Cronquist’s Subclass Dilleniidae; Capparales. APG III core angiosperms; core eudicot; Superorder Rosanae; malvid. APG IV Order Brassicales.

Species 3200. Genera about 350; Acanthocardamum, Aethionema, Agallis, Alliaria, Alyssoides, Alysopsis, Alyssum, Ammosperma, Anastatica, Anchonium, Andrzeiowskia, Anelsonia, Aphragmus, Aplanodes, Arabidella, Arabidopsis, Arabis, Arcyosperma, Armoracia, Aschersoniodoxa, Asperuginoides, Asta, Atelanthera, Athysanus, Aubretia, Aurinia, Ballantinia, Barbarea, Berteroa, Berteroella, Biscutella, Bivonaea, Blennodia, Boleum, Boreava, Bornmuellera, Borodinia, Botscantzevia, Brachycarpaea, Brassica, Braya, Brayopsis, Brossardia, Bunias, Cakile, Calepina, Calymmatium, Camelina, Camelinopsis, Capsella, Cardamine, Cardaminopsis, Cardaria, Carinavalva, Carrichtera, Catadysia, Catenulina, Caulanthus, Caulostramina, Ceratocnemum, Ceriosperma, Chalcanthus, Chamira, Chartoloma, Cheesemania, Cheiranthus (= Erisymum), Chlorocrambe, Chorispora, Christolea, Chrysobraya, Chrysochamela, Cithareloma, Clastopus, Clausia, Clypeola, Cochlearia, Coelonema, Coincya, Coluteocarpus, Conringia, Cordylocarpus, Coronopus, Crambe, Crambella, Cremolobus, Cryptospora, Cuphonotus, Cusickiella, Cycloptychis, Cymatocarpus, Cyphocardamum, Dactylocardamum, Degenia, Delpinophytum, Descurainia, Diceratella, Dichasianthus, Dictyophragmus, Didesmus, Didymophysa, Dielsiocharis, Dilophia, Dimorphocarpa, Diplotaxis, Dipoma, Diptychocarpus, Dithyrea, Dolichirhynchus, Dontostemon, Douepea, Draba, Drabastrum, Drabopsis, Dryopetalon, Eigia, Elburzia, Enarthrocarpus, Englerocharis, Eremobium, Eremoblastus, Eremodraba, Eremophyton, Ermania, Ermaniopsis, Erophila, Erucaria, Erucastrum, Erysimum, Euclidium, Eudema, Eutrema, Euzomodendron, Farsetia, Fezia, Fibigia, Foleyola, Fortuynia, Galitzkya, Geococcus, Glaribraya, Glastaria, Glaucocarpum, Goldbachia, Gorodkovia, Graellsia, Grammosperma, Guiraoa, Gynophorea, Halimolobos, Harmsiodoxa, Hedinia, Heldreichia, Heliophila, Hemicrambe, Hemilophia, Hesperis, Heterodraba, Hirschfeldia, Hollermayera, Hornungia, Hornwoodia, Hugueninia, Hymenolobus, Iberis, Idahoa, Iodanthus, Ionopsidium, Irenepharsus, Isatis, Ischnocarpus, Iskandera, Iti, Ivania, Kernera, Kremeriella, Lachnocapsa, Lachnoloma, Leavenworthia, Lepidium, Lepidostemon, Leptaleum, Lesquerella, Lignariella, Lithodraba, Lobularia, Lonchophora, Loxostemon, Lunaria, Lyocarpus, Lyrocarpa, Macropodium, Malcolmia, Mancoa, Maresia, Mathewsia, Matthiola, Megacarpaea, Megadenia, Menkea, Menonvillea, Microlepidium, Microsysymbrium, Microstigma, Morettia, Moricandia, Moriera, Morisia, Murbeckiella, Muricaria, Myagrum, Nasturtiopsis, Nasturtium (= Rorippa), Neomartinella, Neotchihatchewia, Neotorularia, Nerisyrenia, Neslia, Neuontobotrys, Notoceras, Notothlaspi, Ochthodium, Octoceras, Onuris, Oreoloma, Oreophyton, Ornithocarpa, Orychophragmus, Otocarpus, Oudneya, Pachycladon, Pachymitus, Pachyphragma, Pachypterygium, Parlatoria, Parodiodoxa, Parolinia, Parrya, Parryodes, Pegaeophyton, Peltaria, Peltariopsis, Pennellia, Petiniotia, Petrocallis, Phaeonychium, Phlebolobium, Phlegmatospermum, Phoenicaulis, Physaria, Physocardamum, Physoptychis, Physorrhynchus, Platycraspedum, Polyctenium, Polypsecadium, Pringlea, Prionotrichon, Pritzelago, Pseuderucaria, Pseudocamelina, Pseudoclausia, Pseudofortuynia, Pseudovesicaria, Psychine, Pterygiosperma, Pterygostemon, Pugionium, Pycnoplinthopsis, Pycnoplinthus, Pyramidium, Quezeliantha, Quidproquo, Raffenaldia, Raphanorhyncha, Raphanus, Rapistrum, Reboudia, Redowskia, Rhizobotrya, Ricotia, Robeschia, Rollinsia, Romanschulzia, Roripella, Rorippa, Rytidocarpus, Sameraria, Sarcodraba, Savignya, Scambopus, Schimpera, Schivereckia, Schizopetalon, Schlechteria, Schoenocrambe, Schouwia, Scoliaxon, Selenia, Sibara, Silicularia, Sinapidendron, Sinapis, Sisymbrella, sisymbriopsis, Sisymbrium, Smelowskia, Sobolewslia, Sohms-Laubachia, Sophiopsis, Sphaerocardamum, Spirorhynchus, Spryginia, Staintoniella, Stanfordia, Stanleya, Stenopetalum, Sterigmostemum, Stevenia, Straussiella, Streptanthella, Streptanthus, Streptoloma, Stroganowia, Stubebdorffia, Subularia, Succowia, Synstemon, Synthlipsis, Taphrospermum, Tauscheria, Teesdalia, Teesdaliopsis, Tetracme, Thelypodiopsis, Thelypodium, Thlaspeocarpa, Thlaspi, Thysanocarpus, Trachystoma, Trichotolinum, Trochiscus, Tropidocarpum, Turritis, Vella, Warea, Weberbauera, Werdermannia, Winklera, Xerodraba, Yinshania, Zerdana, Zilla.

General remarks. For family review, see Vaughan, Macleod and Jones 1976.

Economic uses, etc. Important food crops from Brassica (cabbage, cauliflower, broccoli, kohlrabi, turnips, Brussels sprouts); Raphanus (radish); Rorippa (watercress); condiments from Brassica (mustard), Armoracia (horse-radish); ornamentals from about 50 genera, e.g. Arabis, Erysimum (Cheiranthus), Hesperis, Iberis, Lobularia, Lunaria, Matthiola.


When daisies pied, and violets blue,
And cuckoo-buds of yellow hue,
And Lady-smocks all silver-white,
Do paint the meadows with delight
(‘Love’s Labour’s Lost’ — Cardamine pratensis)

Of paramours ne raught he not a kers
(Chaucer, quoted by Ann Pratt 1857 via Jacobs, ‘Flora of Cornwall’. Saxon kers = cress, employed to denote something worthless (i.e. referring to cruciferous weeds, rather than watercress); hence not caring a curse for something — with ‘curse’ later becoming ‘damn’?)

In the season of the tulip cup,
When blossoms clothe the trees,
’Tis sweet to throw the lattice up
And scent thee on the breeze
(Moir, quoted by Ann Pratt, ‘Wild Flowers’ (1857) - of Wallflowers)

And white and purple jiliflowers that stay
Lingering in blossom summer half away
And single blood walls of a luscious smell
Old fashioned flowers which huswives love so well
(John Clare 1827, ‘The Shepherd’s Calendar, June’ — Matthiola and Cheiranthus

‘Shepheards Purse staieth bleeding in any part of the bodie, whether the iuice or the decoction thereof be drunke, or whether it be used pultus wise or in bath or any other wise’.
(John Gerarde, ‘Herball’ 1597 — Capsella bursa-pastoris)

Illustrations. • Le Maout and Decaisne: Cheiranthus, Cochlearia, Parolinia. • Le Maout and Decaisne: Arabis, Barbarea, Lunaria, Tetrapoma (~Rorippa). • Le Maout and Decaisne: Cremolobus, Erophila, Eruca, Megacarpaea, Vesicaria (~Alyssoides). • Le Maout and Decaisne: Aethionema, Iberis, Isatis, Capsella, Lepidium, Neslia, Myagrum, Thlaspi. • Le Maout and Decaisne: Bunias, Clypeola, Crambe, Myagrum, Raphanistrum (~Raphanus), Thysanocarpus. • Arabidopsis thaliana (as Draba thaliana): Eng. Bot. 115, 1863. • Brassica rapa (Turnip) and Brassica rapa ssp. campestris (Wild Turnip) : Eng. Bot. 89 and 90, 1863. • Brassica oleracea (Wild Cabbage) and Brassica napus (Rape): Eng. Bot. 87 and 88, 1863. • Cakile maritima and Crambe maritima: Eng. Bot. 134, 1863. • Cardamine amara, C. pratensis and C. hirsuta: Eng. Bot. 108–110, 1863. • Erophila verna (as 3 forms of Draba verna): Eng. Bot. 134, 1863. • Isatis tinctoria: B. Ent. 734. • Pachycladon novae-zelandii: Hook. Ic. Pl. 11 (1867–71). • Rorippa nasturtium-aquatica (Watercress, as Nasturtium officinalis): Eng. Bot. 125, 1863. • Thysanocarpus curvipes, as T. elegans: Hook. Ic. Pl. 1 (1837). • Brassiceae (Brassica, Diplotaxis: B. Ent. compilation, 1824–35). • Brassiceae (Rhynchosinapis, Cakile, Sinapis: B. Ent. compilation, 1824–35). • Lepidieae (Capsella, Coronopus, Cochlearia: B. Ent. compilation, 1824–35). • Lepidieae (Teesdalia), Drabeae (Erophila), Matthioleae (Matthiola): B. Ent. compilation, 1824–35. • Arabideae (Arabis, Cardamine, Barbarea: B. Ent. compilation, 1824–35). • Arabideae (Rorippa, Dentaria: B. Ent. compilation, 1824–35). • Hesperideae (Erysimum, Cheiranthus, Hesperis: B. Ent. compilation, 1824–35). • Sisymbrieae (Arabidopsis, Descurainia, Alliaria: B. Ent. compilation, 1824–35). • Leaf hairs: Alyssum, Capsella, Cheiranthus, Hesperis, Matthiola (Solereder, 1908).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 15th April 2018.’.