EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, apex multicellular, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem multicellular, interface specific plasmodesmatal network; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids +; tracheid/tracheid pits circular, bordered; sieve tube/cell plastids with starch grains; phloem fibers +; stem cork cambium superficial, root cork cambium deep seated; nodes ?; stomata ?; leaf vascular bundles collateral; leaves megaphyllous [determinancy evolved first, then ad/abaxial symmetry], spiral, simple, axillary buds +[?], prophylls [including bracteoles] two, lateral, veins -5 mm/mm² [mean for all non-angiosperms 1.8]; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores, i.e. no distal pore for release of gametes] +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, with cell walls, with many flagellae; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large", first cell wall of zygote transverse, embryo straight, endoscopic [suspensor +], short-minute, with morphological dormancy, white, cotyledons 2; plastid transmission maternal; two copies of LEAFY gene, PHY gene duplication [N/O//A/C and P//BE lines], mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

Plant woody, evergreen; lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], lignins derived from both coniferyl and sinapyl alcohols, containing syringaldehyde [in positive Maüle reaction, syringyl:guaiacyl ratio less than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0; stem with 2-layered tunica-corpus construction; wood fibers and wood parenchyma +; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides; tracheids +; sieve tubes eunucleate, with a sieve plate and cytoplasm with P-proteins, companion cells from same mother cell that gave rise to the sieve tube; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, veins (1.7-)4.1(-5.7) mm/mm², endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, development in general centripetal, numbers unstable; P not sharply differentiated, outer members not enclosing the rest of the bud, smaller than inner members; A many, with a single trace, introrse, filaments stout, anther ± embedded in the filament, tetrasporangiate, dithecal, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally by action of hypodermal endothecium, endothecial cells elongated at right angles to long axis of anther; tapetum glandular, binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous or microperforate, ektexine columellar, endexine thin, compact, lamellate only in the apertural regions; nectary 0; G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, [outer integument often largely subdermal in origin, inner integument dermal], micropyle endostomal, integuments 2-3 cells thick, nucellus at apex of ovule 1-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte four-celled [one-modular, nucleus of egg cell sister to one of the polar nuclei], stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; P deciduous in fruit; seed exotestal; pollen germinating in less than 3 hours, siphonogamy, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm; tube moves between nucellar cells, double fertilisation +, endosperm diploid, cellular [first division oblique, micropylar end initially with a single large cell, chalazal end more actively dividing], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)_n]; whole genome duplication, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and PHYA + C/PHYB + E gene pairs.

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable variation between families in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous... For other features such a a nucellus only one (Nymphaeales) to three cells thick above the embryo sac and a stylar canal lacking an epidermal layer, although plesiomorphous for basal grade angiosperms (Williams 2009), where on the tree a thicker nucellus and a stylar epidermal layer are acquired has not yet been indicated.

NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessels + [one position], elements with elongated scalariform perforation plates; axial parenchyma diffuse or diffuse-in-aggregate; tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

VITALES + ROSIDS: anthers articulated [± dorsifixed, transition to filament narrow, connective thin].

ROSIDS: embryo long; genome duplication; chloroplast infA gene defunct, mitochondrial coxII.i3 intron 0.

MALVIDAE = [[GERANIALES + MYRTALES] [CROSSOSOMATALES [PICRAMNIALES [SAPINDALES [HUERTEALES [MALVALES + BRASSICALES]]]]]]: ?

CROSSOSOMATALES [PICRAMNIALES [SAPINDALES [HUERTEALES [MALVALES + BRASSICALES]]]]: ?

PICRAMNIALES [SAPINDALES [HUERTEALES [MALVALES + BRASSICALES]]]: 2 apical pendulous ovules/carpel.

SAPINDALES [HUERTEALES [MALVALES + BRASSICALES]]: flavonols +; vessel elements with simple perforation plates; (cambium storied); petiole bundle(s) annular; inner integument thicker than outer, style +; endosperm scanty.

HUERTEALES [MALVALES + BRASSICALES]: ?

MALVALES + BRASSICALES: ?

BRASSICALES Bromhead  Main Tree, Synapomorphies.

Idioblastic and stomatal myrosin cells +, glucosinolates from phenyalanine and/or tyrosine [aliphatic glucosinolates], idioblastic and stomatal myrosin cells +, little oxalate accumulation; endoplasmic reticulum with dilated cisternae; myricetin, other methylated flavonols, tannins 0; vasicentric axial parenchyma +; tension wood?; mucilage cells in leaf 0; leaves spiral, stipules small; inflorescence racemose; (petals clawed); G [3], ovules in one or two rows; seed coat?; embryo often green. - 17 families, 398 genera, 4450 species.

Evolution. The earliest fossil known is from the Turonian, ca 89.5 million years before present. Wikström et al. (2001: relationships are [Brassicales - Tropaeolum, etc., not included [Malvales + Sapindales]]]) date the origin of stem Brassicales to (89-)85(-81) million years before present, diversification beginning (75-)71(-67) million years before present. The age of crown group Brassicales was estimated as (76-)73(-70) and (63-)69(-57) million years (two penalized likelihood dates), the stem group age being (94-)89(-85) or (80-)74(-68) million years; Bayesian relaxed clock estimates were slightly different, to 46 and 96 million years respectively (Wang et al. 2009), while Magallón and Castillo (2009) estimated ages of ca 91.9 and 92.1 million years for relaxed and constrained penalized likelihood datings for the age of stem Brassicales, and ages of 65.8 and 66 million years for the crown group.

Brassicales contain ca 2.2% eudicot diversity (Magallón et al. 1999).

Nearly all the glucosinolate-producing families of flowering plants are in this clade (c.f. Kjær 1974; Dahlgren 1975). Glucosinolates are mustard oil glycosides, and mustard oils themselves are esters of isothiocyanic acid, which contain a R—N=C=S group and have a pungent smell and a sharp taste. Specialised, protein-rich myrosin cells contain enzymes like thioglucoside glucohydrolase (a ß-thioglucohydrolase, or myrosinase), that breaks down glucosinolates into glucose and aglucones when plant tissue is damaged by a herbivore and enzyme and substrate are brought into contact. The latter then automatically rearrange and form toxic isothiocyanates, or are converted into thiocyanates (mustard oils), nitriles (not necessarily toxic) and other compounds. This is the "Senfölbombe" or "mustard oil bomb" (see Rask et al. 2000, Wittstock et al. 2003; Grubb & Abel 2006; Halkier & Gershenzon 2006; Agerbirk et al. 2008; Burow et al. 2009 for details, most of which have been worked out in Brassicaceae; Bones & Rossiter 2006 particularly for glucosinolate degradation). Note that not all taxa producing mustard oils have myrosin cells. The ß-glucosidase involved is similar to those that break down cyanogenic glycosides, and there is en evolutionary link between the synthesis of glucosinolates and that of cyanogenic compounds (Halkier & Gershenzon 2006; Morant et al. 2008).

Glucosinolates themselves are synthesised from valine/isoleucine and/or leucine in several families of Brassicales, i.e. they are aliphatic glucosinolates, but these are not found in families in the terminal polychotomy (Rodman 1991a, for data) - could this be another synapomorphy for the order? Note that not all taxa producing mustard oils have myrosin cells, and even in Brassicaceae, which do, such cells may be absent in the young plant (Maile 1980). In many Brassicales myrosinases occur in large quantities in the guard cells (Jørgensen 1995), and in Brassicaceae, at least, they have become involved in the signaling mechanisms of stomatal opening and closure (Zhao et a. 2008) even although that family lacks stomatal myrosin cells. Attempts are being made to engineer glucosinolates into non-glucosinolate-containing plants such as tobacco (Geu-Flores et al. 2009); anybody for cabbage-tasting tobacco?

Caterpillars of Pieridae-Pierinae (foodplants of ca 360 species in 33+ genera recorded, 840 species in the clade; ca 1/3 of all records) are commonly found on members of this order (Fraenkel 1959; Ehrlich & Raven 1964; Braby & Trueman 2006; Braby et al. 2006), including Bretschneidera; they are abundant only in the Capparaceae-Cleomaceae-Brassicaceae clade. Pierinae may have moved to Brassicales from an original host in Fabaceae (Braby & Trueman 2006) some (90-)85(-60) million years ago, within ten million years or so of the origin of Brassicales (Wheat et al. 2007). This is associated with the evolution of a novel glucosinolate detoxifying mechanism in these butterflies, which are more diverse than more basal clades without this mechanism (Wheat et al. 2007). After a gene duplication, one of the orthologs produced an enzyme that detoxified glucosinlates by producing nitriles rather than toxic isothiocyanates on their hydrolysis (Fischer et al. 2008). Relationships between herbivores and plants - again, nearly all information comes from Brassicaceae - are complex, but specialised feeders - and their hymenopteran parasites - may be attracted by isothiocyanates (Hopkins et al. 2009 and references). Some chrysomelid beetles also favor Brassicales, for example, Phyllotreta (Alticinae - see Jolivet & Hawkeswood 1995), while the dipteran leaf miner Liriomyza brassicae is found on Resedaceae, Cleomaceae, Tropaeolaceae and Brassicaceae (Spencer 1990).

Rodman et al. (1996) suggest a number of apomorphies for the order (and some nodes within it), but where some characters are to be placed on the tree is unclear.

Chemistry, Morphology, etc. For unrelated glucosinolate-containing families, see Putranjivaceae (Malpighiales) and perhaps also - but probably not - Phytolaccaceae (Caryophyllales) and Pittosporaceae (Apiales: Fahey et al. 2001 for a summary). It has also been suggested that Oceanopapaver, a genus of uncertain affinities but now pretty firmly associated with Malvaceae (= Corchorus), has myrosin cells; this, too, is unlikely (Whitlock et al. 2003). A report of ellagic acid in "Capparidaceae" (Bate-Smith 1962) needs to be confirmed; Zindler-Frank (1976) lists seven families scattered throughout the order as having little oxalate accumulation. Many taxa seem to have diarch roots, although not some Cleomaceae; sampling in the basal pectinations is poor. Note that most families have stipules, albeit small. Strongly developed and fused ventral carpellary bundles may be another synapomorphy for the order (Ronse de Craene & Haston 2006).

For general information, see Villers (1973), Mehta and Moseley (1981), Jørgensen (1981, 1995), Carlquist (1985a), Tobe and Peng (1990), Fisch and Weberling (1990), Rodman (1991a, b), Link (1992a), Rodman et al. (1993, 1994), Tobe and Takahashi (1995), Hufford (1996), Doweld (1996a, b), Ronse Decraene and Smets (1997) and Kubitzki (2002a, b: as Capparales).

Phylogeny. Relationships within Brassicales show a fair bit of structure (see tree), as Rodman et al. (1997, 1998), Carol et al. (1999), Chandler and Bayer (2000), Kubitzki (2002a), Olson (2002) and Hall et al. (2004) have found. Ronse de Craene and Haston (2006) examine morphological evolution in the clade in the context of a combined molecular (four genes, but some taxa included in the analysis lacking up to three of them) and morphological study; it is unclear what significance to attach to differences in details of the topology of the tree presented there and that used here. Analysis of morphological data alone yielded only one clade (Polanisia + Cleome!) in Brassicales with even weak support, and Bretschneidera and Akania were associated with Sapindaceae (Ronse de Craene & Haston 2006). However, that paper should be consulted for details of floral anatomical/morphological evolution in Brassicales. For the relationships of Emblingiaceae, sometimes associated with Gentianales, see below.

Previous Relationships. Some Brassicales, Brassicaceae and their immediately related families, have always been placed together based on morphological similarity and chemistry (smell!), but until quite recently the others have been widely separated. Many brassicalean families are included in Violanae (Dilleniidae) by Takhtajan (1997), but Gyrostemonales are in Gyrostemonanae (Caryophyllidae) and Limnanthales in Solananae (Lamiidae). Cronquist (1981) placed Brassicales in Violales (Caricaceae), Capparales (several families), Batales (Gyrostemonaceae, Bataceae), all scattered through Dilleniidae, also in Geraniales (Limnanthaceae) and Sapindales (Akaniaceae), both in Rosidae, etc. Rolf Dahlgren began the process of pulling the order together (e.g. R. Dahlgren 1975a; G. Dahlgren 1989, and references; summary in Jørgensen 1995).

Includes Akaniaceae, Bataceae, Brassicaceae, Capparaceae, Caricaceae, Cleomaceae, Emblingiaceae, Gyrostemonaceae, Koeberliniaceae, Limnanthaceae, Moringaceae, Pentadiplandraceae, Resedaceae, Salvadoraceae, Setchellanthaceae, Stixaceae, Tovariaceae, Tropaeolaceae.

Synonymy: Akaniales Doweld, Batales Engler, Capparales Huchinson, Caricales L. D. Benson, Gyrostemonales Takhtajan, Limnanthales Nakai, Moringales Nakai, Resedales Dumortier, Salvadorales Reveal, Tovariales Nakai, Tropaeolales Reveal - Capparanae Reveal, Gyrostemonanae Takhtajan

Akaniaceae + Tropaeolaceae: vessel elements with scalariform perforation plates; axial parenchyma sparse, adjacent to vessels; bracteoles 0; flowers quite large, obliquely monosymmetric, K/C tube +, C clawed; A 8, with short connective prolongations, placentation apical-axile, 1-2 epitropous ovules/carpel, style long; testa vascularised.

Chemistry, Morphology, etc. It is possible that Tropaeolaceae have basically pinnate leaves (Endress 2003c), a matter than can perhaps be cleared up by further developmental studies. This may yield another synapomorphy for the clade. Although both families have a nectary, it is extrastaminal in Tropaeolaceae and intrastaminal in Akaniaceae. Furthermore, exactly which stamens are reduced and details of the plane of asymmetry of the flowers differ between Tropaeolum and Bretschneidera; the former is obliquely asymmetric only in bud (Ronse Decraene et al. 2002a; Ronse Decraene & Smets 2001). Finally, the hypanthium is described as "lifting sepal lobes and petals high above the stamen insertion" by Ronse Decraene et al. (2002a: p. 44), i.e., it is a calyx/corolla tube in the strict sense; there is also a true hypanthium in Bretschneidera, at least, although it is not evident in the Tropaeolum examined by Ronse Decraene and Smets (2001).Carlquist and Donald (1996) give additional characters of wood anatomy that unite these two families.

AKANIACEAE Stapf, nom. cons.   Back to Brassicales

Deciduous or evergreen trees; tannins?; cork subepidermal; young stem with separate bundles; (vessel elements with simple perforation plates); no bordered pits in imperforate tracheary elements; petiole bundle?; cuticle waxes 0, strong cuticular cracks; stomata ?; leaves odd-pinnate, leaflets spinulose-toothed or entire, supervolute-curved, petiolules swollen or articulated; (inflorescence branched); K ± connate, C contorted or not; A 8, or 3 (4) abaxial in the whorl opposite petals [Akania], pollen colpate, disc + or 0, 2 (campylotropous - Bretschneidera) ovules/carpel, micropyle bistomal, stigma small, 3-lobed; fruit a septicidal capsule; testa multiplicative, exotestal cells palisade, thick-walled, mesotesta ± thick, cells thick-walled, endotesta thickened; endosperm development?, copious or not, embryo color?, cotyledons large; n = 9 [Bretschneidera].

2[list]/2. S.W. China, adjacent Vietnam, Formosa (Bretschneidera sinensis [Photo - Collection]), E. Australia (Akania bidwillii).

Chemistry, Morphology, etc. The seeds of Akania have endosperm and the plant may lack myrosin cells, but wood of the two genera is almost identical. In Bretschneidera, glucosinolates are also produced from valine/isoleucine and/or leucine, the leaflets are entire, the flowers are clearly strongly obliquely monosymmetric, the stamens are curved and held under one petal, there is a disc, and the embryo sac is bisporic and 8-nucleate. For ovules, see Mauritzon (1936). I have seen neither fresh vegetative material of Bretschneidera nor flowers of Akania. Seedlings of Akania initially produce at least five simple leaves with pinnate venation.

For general information, see Bayer and Appel (2002).

Classification. Separating Bretschneideraceae from Akaniaceae was considered optional in A.P.G. II (2003), however, there seems nothing lost in combining them (see A.P.G. 2009).

Previous Relationships. A relationship with Sapindales has often been suggested (e.g. Carlquist 1997a), but in this case perhaps largely because Sabiaceae were included in the latter; an analysis of morphological data also suggested this position (Ronse de Craene & Haston 2006). Bretschneideraceae do look rather sapindaceous.

Synonymy: Bretschneideraceae Engler & Gilg, nom. cons.

TROPAEOLACEAE Berchtold & J. Presl, nom. cons.   Back to Brassicales

Fleshy vine with twining petioles; glucosinolates also from valine/isoleucine and/or leucine, only idioblastic myrosin cells, erucic acid [fatty acid] +; cork cambium deep seated? to more superficial; stem with separate bundles; petiole bundles annular; pericyclic fibers 0; cuticle waxes tubular; leaves flat in bud, palmately lobed (palmate), peltate or not, toothed to entire, stipules small, in seedling only, to fringed, subfoliaceous and throughout the plant; flowers often axillary, (bracteoles +); hypanthium ?, adaxial K (3 connate) spurred, C 2 + 3 (+ 2), clawed; A 8, pollen trinucleate, median carpel adaxial, 2 tenuinucellate ovules/carpel, micropyle endostomal, styles short, trifid in appearance, stigma dry; fruit a schizocarp (samara), mericarps drupaceous or nutlike, K deciduous; seed pachychalazal, coat undistinguished, part of mesotesta suberized; amyloid in cotyledons, suspensor haustoria penetrate micropyle; n = 12-15.

1/95. New World (map: see Sparre & Andersson 1991). [Photos - Tropaeolum Flower, Tropaeolum Flower]

• Tropaeolaceae are rather fleshy vines with twining petioles. The broad leaf blades have palmate venation and may be palmately-lobed, palmate or peltate. The flowers are large, strongly monosymmetric, and have an adaxial calycine spur, five clawed petals, and eight stamens. The fruit is usually a three-lobed schizocarp, and each unit contains but a single seed.

Chemistry, Morphology, etc. Carlquist and Donald (1996) report vague storying of the secondary phloem of the root. For an interpretation of the axillary flowers common in Tropaeolum, see Bayer and Appel (2002). The nectary may be hypanthial (Troll 1957) and ends up in the spur; it is outside the stamens (Ronse Decraene et al. 2002). The median carpel is actually slightly off the median (Eichler 1878; Ronse Decraene & Smets 2001); two antepetalous stamens are suppressed (Ronse Decraene et al. 2002). There are initially two ovules per carpel, but one does not develop very far. The developing seed has a suspensor haustorial system (Walker 1947).

Phylogeny. For phylogenetic relationships in the family, see Andersson and Andersson (2000). Distinctive reproductive morphologies - Magallana, with its winged fruits, and Trophaeastrum, which lacks a nectary spur - are derived from within the general Tropaeolum morphology of spurred flowers and simple schizocarpic fruits.

Classification. There is only a single genus in the family since the recognition of Magallana and Trophaeastrum would make Tropaeolum paraphyletic (Andersson & Andersson 2000).

[Moringaceae + Caricaceae] [Limnanthaceae [Setchellanthaceae [[Koeberliniaceae [Bataceae + Salvadoraceae]] [Emblingiaceae [Pentadiplandraceae [Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]]]]]]: several [³6] ovules/carpel.

Moringaceae + Caricaceae: woody, stems stout; endoplasmic reticulum-dependent vacuoles; cambium storied; nodes also multilacunar; cuticle wax platelets as rosettes; venation palmate, colleters on petiole/lamina, stipules as glands; inflorescences thyrses; flowers whitish; G opposite sepals, ovary longitudinally sulcate, placental strands opposite the ventral bundles +, placentation parietal, many ovules/carpel, outer integument 5-6 cells across, micropyle bistomal, style hollow; testa multiplicative, mesotesta ± lignified.

Chemistry, Morphology, etc. Ronse de Craene and Haston (2006) suggest that nodes are unilacunar in this clade; they are tri or multilacunar. The sulci in the ovary are in the interplacental position. Whether or not the thickened mesotesta of the two families is comparable needs to be confirmed, certainly there are substantial anatomical differences in the seed coat (Olson 2002a).

Phylogeny. For relationships in this clade, see Olson (2002a).

MORINGACEAE Martynov, nom. cons.   Back to Brassicales

Deciduous trees or shrubs (stem succulents); glucosinolates also from valine/isoleucine and/or leucine; hairs unicellular; schizogenous gum canals +; leaves odd-pinnate, 1- or 3-compound; flowers obliquely monosymmetric; hypanthium short (long), lined with nectary, K petaloid, median [abaxial] C usu. larger than others, stamens = and opposite petals, declinate, monothecal, staminodes +, opposite sepals, gynophore +; G ([2-4]), micropyle zig-zag, endothelium +, style slender, stigma truncate-porate; fruit a 3-angled explosively-dehiscent effectively loculicidal capsule; seeds 3-angled, winged (not), testa vascularised, mesotesta thick, outer and inner parts with helical thickenings, middle part much thickened, tegmen thin, (multiplicative); n = 11, 14.

1[list]/12. India to Africa, Madagascar, Moringa oleifera is quite widely cultivated (map: from Olson 2001). [Photo - Flower, Collection]

• Moringaceae are woody, often quite stout-stemmed shrubs or trees whose foliage often smells unpleasantly when crushed. They are recognisable by their spiral, deciduous, odd-pinnate, 1- to 3-compound leaves that have conspicuous glands at the articulations and at the base; often clearly obliquely monosymmetric and papilionoid flowers (the median petal is adaxial) with five stamens; and long, slender, tricarpellate, three-angled, capsular fruits.

Evolution. Olson and Rosell (2006) suggest that heterochrony is involved in the evolution of the various life forms in the family; the bottle-tree growth form is probably plesiomorphic, the tuberous shrub growth form is probably derived (see also Olson 2006 for wood anatomy). All species have rather fleshy roots/rootstock and are usually to be found in more or less arid habitats.

Chemistry, Morphology, etc. For wood anatomy, see Olson and Carlquist (2001); there are reports of vestured pits from the family (Jansen et al. 2001b). Even although flowers of all species are slightly monosymmetric early in development (Olson 2002b), flowers at anthesis may be polysymmetric or strongly monosymmetric. When flowers are monosymmetric, they are borne with the median petal adaxial, and when they are polysymmetric the median petal is in the normal abaxial position (Olson 2003). Carpel orientation is in the plane of symmetry of the flower (Ronse Decraene et al. 1998). Seeds are borne along the middle of the valves which means that dehiscence is effectively loculical given that the placentation is parietal. The seedlings have either palmately compound leaves or simple leaves with palmate venation (M. Olson, pers. comm.).

Some general information is taken from Ernst (1963), who described the ovules as being apotropous. Kubitzki (2002d) and the Moringa website (Olson, 1999) summarize information on the family.

Phylogeny. For relationships, see Olson (2000b).

Synonymy: Hyperantheraceae Link

CARICACEAE Burnett, nom. cons.   Back to Brassicales

(Viny, but with stout tuber), usu. prickly; only stomatal myrosin cells; articulated laticifers +, anastomosing; leaves palmately-veined or strongly lobed (palmate), flat-curved to involute, glands on adaxial surface at base; plants di(mon)oecious, inflorescences axillary, cymose; staminate flower: K connate, small, C connate, contorted or valvate, stamens adnate to corolla, 10, of two lengths, the longer opposite the sepals, and whorled, or = and opposite sepals, connective often developed, nectary on pistillode; carpellate flowers: as above, but C often free; A 0, nectary 0; G [5], (placentation axile), styles ± separate, stigmas flabellate or almost petaloid (capitate), dry; fruit a berry; sarcotesta +, mucilaginous, mesotesta tanniniferous, with lignified ribs, endotesta crystalliferous (lignified), exotegmen fibrous [?sclereidal?]; embryo white; n = 9.

4(-6)[list]/34: Carica 23. Mostly tropical America (three genera in Mexico); Africa (Cylicomorpha only) (map: from Badillo 1971). [Photo - Plant, Flower, Fruit]

• Caricaceae are stout-stemmed often prickly trees, rarely vines, with flowing, latex-like exudate and palmately-compound or -lobed leaves. The inflorescences are axillary, cymose, and the flowers - always imperfect - are moderate in size. The fruit is a rather large berry and contains numerous seeds borne on five parietal placentae and each surrounded by mucilage.

Evolution. Jacaratia has carpellate flowers with white, spreading stigmas perhaps mimicking the androecium of staminate flowers, but nectar is produced only in the staminate flowers (Bawa 1980).

Chemistry, Morphology, etc. Reports of cyclopentenoid cyanogenic glycosides in the family have been questioned (Jørgenson 1995). Some general information is taken from Badillo (1971), Miller (1982) and Kubitzki (2002d); for embryology, see Singh (1970), wood anatomy, see Carlquist (1998c); and for floral development, see Ronse Decraene and Smets (1998b).

Phylogeny. For phylogenetic relationships, see Kyndt et al. (2005). Geographical relationships are interesting, since the African Cylicomorpha is sister to the rest of the family, which are American.

Previous Relationships. Cronquist (1981) includind Caricaceae in his Violales sandwiched between Achariaceae in the restricted sense (more or less herbaceous, South African) and the North American Fouquieraceae; Takhtajan (1997) placed his monofamilial Caricales in a generally similar position, i.e. along with other families that have parietal placentation.

Setchellanthaceae [Limnanthaceae [[Koeberliniaceae [Bataceae + Salvadoraceae]] [Emblingiaceae [Pentadiplandraceae [Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]]]]]: nodes 1:1; extended 3' terminus of rbcL gene.

Chemistry, Morphology, etc. For the extended 3' terminus of rbcL gene, see Karol et al. (1999).

Phylogeny. Setchellanthus comes out just basal to Limnanthaceae in molecular phylogenies (Karol et al. 1999, support weak, see also Rodman et al. 1997; Chandler & Bayer 2000). Its inclusion in this clade is very strongly supported (e.g. Karol et al. 1999).

SETCHELLANTHACEAE Iltis   Back to Brassicales

Shrub; hairs unicellular, T-shaped, on multicellular podium; myrosin cells 0; young stem with vascular cylinder; ?stomata; 2ndary veins subbasal, stipules 0; flowers axillary, large, (5)6(7)-merous; K connate, splitting irregularly, C clawed; A many, centrifugal, in 5-7 groups on elongated axis, pollen tricolpate, nectary 0, gynophore short, placentation axile, 10-14 ovules/carpel in two ranks, style short, stigmas subcapitate; fruit a septifragal capsule, central columella persistent; testa soft, endosperm development?, scanty; n =?

1/1: Setchellanthus caeruleus. Mexico (map: see Iltis 1999). [Photos - Flower, Flower, Fruit]

• Setchellanthaceae are pungent-smelling shrubs that may be recognised by their large, blue, axillary flowers with parts usually in sixes and an irregularly-splitting calyx. Vegetatively the plant is rather undistinguished, although it has T-shaped hairs and the rather small, entire, exstipulate leaves have secondary veins arising from near the base and lack much in the way of a petiole. The three-carpellate fruit is septifragal and there is a persistent columella.

Chemistry, Morphology, etc. The fusion of the marginal ventral carpellary bundles is commissural. Some information is taken from Carlquist and Miller (1999: anatomy), Iltis (1999: general), Tobe et al. (1999: flowers), Tomb (1999: pollen), and Kubitzki (2002d: general).

Previous Relationships. Setchellanthus used to be included in Capparaceae.

Limnanthaceae [[Koeberliniaceae [Bataceae + Salvadoraceae]] [Emblingiaceae [Pentadiplandraceae [Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]]]]: root hairs in vertical files.

Chemistry, Morphology, etc. Root trichoblasts have been sampled in rather few families. The distinctive vertical files of root hairs are known from Limnanthaceae and some terminal members of Brassicales, and although they have not been observed in Tropaeolaceae other Brassicales basal to Limnanthaceae have not been studied (Dolan & Costa 2001).

LIMNANTHACEAE R. Brown, nom. cons.   Back to Brassicales

Herbs; erucic acid, ellagic acid, myricetin, leucoanthocyanins +, isokestose oligosaccharides as storage, only idioblastic myrosin cells; cork?; leave blades pinnate(ly lobed), conduplicate, margin with teeth, stipules 0; (flowers single, axillary, bracteoles 0); flowers 3-5-merous, K valvate, C contorted; A 2x K, of two lengths (equal and opposite sepals), pollen zonosulcate, nectaries on abaxial bases of antesepalous A (0), G [2-5], opposite sepals, when 3 median member abaxial, placentation basal-parietal, 1 apotropous tenuinucellate unitegmic ovule/carpel, embryo sac tetrasporic, 4- or 6-nucleate, style gynobasic, simple, hollow, or branches ± well developed, stigma punctate to minutely capitate, dry; fruit a schizocarp, mericarps muriculate, K persistent; seed coat pachychalazal, thick, with vascular bundles, otherwise undistinguished; endosperm haustorium +, embryo color?, cotyledons cordate, with amyloid; n = 5.

1(2)[list]/8. Temperate North America (map: from Culham 2007). [Photo - Flower] [Photo - Flower (close-up)]

• Limnanthaceae are rather soft-stemmed herbs with spiral, exstipulate, deeply-lobed or compound leaves and rather open flowers with a valvate calyx, contorted corolla, and gynobasic style or styles. The fruit is a schizocarp separating into shortly spiny, one-seeded portions (mericarps).

Chemistry, Morphology, etc. The ovules of Limnanthaceae differ from those of other Brassicales, which are usuaully crassinucellate, bitegmic, and with a monosporic, 8-nucleate embryo sac (but see Akaniaceae), but chemistry and molecular data place them here. According to van Tieghem (1898), the integument is very thick and the ovules are epitropous, while Johri (1970) described an endosperm pouch or haustorium on the funicular side of the micropyle region.

Some information is taken from Link (1992a) and that on wood anatomy from Carlquist and Donald (1996); for general information, see Bayer and Appel (2002).

Previous Relationships. Limnanthaceae were often included in Geraniales (e.g. Cronquist 1981), but their androecium is diplostemonous (that of Geraniaceae, at least, is obdiplostemonous), the ovules are apotropous (epitropous), and carpel orientation differs (Eckert 1966). Limnanthaceae were placed in Solananae by Takhtajan (1997).

[Koeberliniaceae [Bataceae + Salvadoraceae]] [Emblingiaceae [Pentadiplandraceae [Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]]]: glucosinolates from chain-elongated branched-chain amino acids; ovules campylotropous, styles short to absent; seeds exotegmic, exotegmen fibrous; embryo strongly curved.

Chemistry, Morphology, etc. Amino acids like isoleucine with branched chains may have additional carbons along the chain; the occurrence of such chain-elongated branched-chain amino acids is to be pegged here on the tree (J. E. Rodman, pers. comm.). There is extensive variation of floral merism in the Emblingiaceae-Brassicaceae group in particular, but 4-merous flowers could be an apomorphy at this level - but with plenty of reversals. A fibrous, if unlignified, exotegmen may well be another apomorphy; it has, for example, been reported from Koeberliniaceae, Salvadoraceae, Resedaceae, Cleomaceae, etc. As Tobe and Raven (2008) suggest, optimisation of this and other embryological features on the tree is unclear; if ovule and seed characters are placed at this node, they reverse in [Bataceae + Salvadoraceae].

Koeberliniaceae [Bataceae + Salvadoraceae]: idioblastic myrosin cells 0; flowers 4-merous, pollen 3-colporoidate; G [2]; fruit indehiscent; exotestal cells well developed; n = 11.

Chemistry, Morphology, etc. For variation in and possible synapomorophies of this group, see Ronse Decraene and Wanntorp (2009).

KOEBERLINIACEAE Engler, nom. cons.   Back to Brassicales

Woody, thorny; ellagic acid?, tannins?; no glucosinolates; cork pericyclic; perforation plates bordered; pits vestured; intercellular canals +; leaves minute, fugacious, stipules 0; inflorescences axillary, (flowers 5-merous); A (10); tapetal cells multinucleate; nectaries at the base of A; G with gynophore, oblique, style +, stigma ± minutely expanded; placentation axile, ovules ca 10/carpel, tenuinucellate, apotropous and epitropous, nucellar epidermal cells radially enlarged, outer integument 2 cells across, non-multiplicative, micropyle zig-zag; fruit a berry; exotesta with massive cuticle, then tanniniferous cells, exotegmen walls very thick, lignified, cells moderately elongated [fibrous]; embryo green, endosperm type?, moderate, cotyledons incumbent.

1/2. C. and S.W. North America, Bolivia (map: from Holmes et al. 2009). [Photo - Habit] [Photo - Flower]

• Koeberliniaceae are thorny, much-branched shrubs of dry regions; the prophylls are basal on the branches/thorns. The flowers are small and undistinguished, and the fruit is a few(1-2)-seeded berry terminated by the persistent style.

Chemistry, Morphology, etc. The ovules look as if they may be campylotropous (see also Tobe & Raven 2008). Nodal anatomy is taken from that of the bracts (Mehta & Moseley 1981). For anatomy, see Gibson (1979), for floral anatomy, see Mehta and Moseley (1981), for embryology, see Tobe and Raven (2008), and for general information, see Kubitzki (2002d); von Schrenk, Aug. 8, Texas - seed anatomy.

Classification. See Holmes et al. (2009) for a monograph.

Previous Relationships. Canotia, sometimes placed here (e.g. Hutchinson 1973), is included in Celastraceae. Both are thorny shrubs, but that is the main extent of their similarity. Koeberlinia itself has been included in Capparaceae (Cronquist 1981).

Bataceae + Salvadoraceae: wood ± storied; perforation plates not bordered; rays wide, multiseriate; nodes 1:2; stomata paracytic; leaves opposite, with 2ndary veins ascending from at or near base; bracts with colleters on their tips; pollen psilate; G (2); 2 basal ovules/carpel; exotegmen not fibrous; endosperm 0, embryo ± straight, color?

Chemistry, Morphology, etc. Azima has two trace-one gap nodes to the bracts and bracteoles, Salvadora has one trace, one gap nodes to the bracts (Kshetrapal 1970). R. A. Howard (pers. comm.) reported two trace, one gap nodes from both genera. The two families are very similar morphologically (Rodman et al. 1996) and anatomically (Carlquist 2002a), while Ronse de Craene and Haston (2006, see also Ronse de Craene & Wanntorp 2009) list a number of other features the two families share including colleter-like stipules, flowers that are slightly monosymmetric and horizontally oriented relative to the inflorescence axis, a sepal tube, endostomal micropyle, etc. The flowers of neither family are easy to interpret.

BATACEAE Perleb, nom. cons.   Back to Brassicales

Fleshy shrublets; (hydroxy)proline betaines +, tannins?; cork pericyclic; perforation plate borders vestigial; pits vestured; leaves fleshy, stipules unvascularised, intrapetiolar or cauline; plant monoecious or dioecious, inflorescences usually axillary, densely spicate; flowers small, bracteoles 0, nectary 0; staminate flowers: K 2, median, enveloping flower, or K 4, connate; P clawed; A = and alternate with P; pollen ektexine spongy, undifferentiated; carpellate flowers: P 0; G 4-locular [carpels subdivided], stigmas sessile, capitate-penicillate; ovules collateral, epitropous, micropyle ± zig-zag, nucellar cap +; fruit multiple, or a drupe with four pyrenes; seed coat membranous.

1[list]/2. N. Australia and S. New Guinea, tropical America, and the Galapagos (introduced into the Hawaiian Is.) (map: from van Steenis & van Balgooy 1966; Heywood 1978; George 1982). [Photo - Flowers]

• Bataceae are halophytic subshrubs with opposite, small, entire, fleshy leaves that have minute "stipules". The flowers are staminate or carpellate and aggregated into dense, spicate, more or less strobilate, inflorescences. The carpellate flowers lack bracts or perianth and are fused together to form a compound fruit.

Chemistry, Morphology, etc. For the nodal anatomy of Batis maritima, with what is presumably the foliar trace disappearing as it approaches the node, the leaf being supplied by two bundles from the angles of the stem, see van Tieghem (1893), but cf. Johnson (1935) and R. A. Howard (pers. comm.). The stipules need study: van Tieghem reports them to be absent, Johnson (1935) that they are between the broad leaf base and the stem, Rogers (1982b) that they are cauline, while Ronse De Craene (2005) in a floral study describes the fairly massive structures in this position in the flowers as being colleters (note that these descriptions are not all mutually exclusive). The morphological nature of the structure enveloping the staminate flowers is most obvious in B. argillicola, but there is controversy over the nature of this structure, too. Ronse De Craene (2005) described it as being derived from four sepals in Batis maritima, although he noted that it had only a single vascular trace; some of the lobing of the tubular structure may in fact be caused by pressure from other parts of the developing flower rather than reflecting an inherently four-merous tube.

Batygina et al. (1985) provide information on the ovules, for pollen, see Tobe and Takahashi (1995), for floral development of Batis maritima, see Ronse De Craene (2005), and for general information, see Bayer and Appel (2002).

SALVADORACEAE Lindley, nom. cons.   Back to Brassicales

Woody; tannins 0; cisternae of endoplasmic reticulum dilated, but no myrosin cells at all; cork superficial; wood storied; included phloem +; cuticle waxes with platelets; leaf ptyxis flat-curved [Salvadora]; plant dioecious or polygamous, or flowers bisexual; (C/A tube +, short [Salvadora]); K 2-4(-5), contorted, basally connate, C (5), contorted or imbricate, (connate); A = and opposite sepals, free, basally connate, or adnate to C, pollen?, nectar glands alternating with or abaxial to A or 0; G 1-2-4-locular [?false septae], (gynophore +; oblique [Salvadora]), (style +, short), stigma at most slightly lobed; 1-2 apotropous ovules/carpel, outer integument 10-15 cells across, micropyle endostomal, (obturator +); fruit a berry or drupe; exotestal cells palisade, slightly thickened, inner walls mucilaginous, crystalliferous, tegmen becoming crushed, exotegmic cells fibrous, not lignified; cotyledons thick; n also = 12.

3[list]/11: Salvadora (5). Africa (inc. Madagascar) to South East Asia and West Malesia, often in drier regions (map: from Aubréville 1974 - Malesian distribution rather optimistic, perhaps only in Java). [Photo - Habit, Fruits]

• Salvadoraceae are rather small-leaved shrubs, sometimes scrambling, or small treees with opposite, rather leathery leaves; small, 4-merous flowers with connate sepals and two carpels with a short style; and a fleshy fruit.

Chemistry, Morphology, etc. For wood anatomy, see Carlquist (2002a), for general information, see Kubitzki (2002d). The stipules of Salvadora persica are described as being colleter-tipped, the flowers may be slightly monosymmetric and there may be a poorly developed petal-stamen cup (Ronse de Craene & Wanntorp 2009). Ronse de Craene and Wanntorp (2009) descibe the gynoecium as probably originally being bicarpellate and with parietal placentation; if the ovary appears to have two loculi it is because of the development of a structure perhaps comparable to the false septum of Batis.

Synonymy: Azimaceae Wight & Gardner

Emblingiaceae [Pentadiplandraceae [Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]]: Glucosinolates also from tryptophan [= indole glucosinolates: Embl. + Gyro. unknown] +; cisternae of endoplasmic reticulum dilated and vacuole-like; cuticle wax crystalloids 0; inflorescence terminal, racemose, bracteoles 0; floral development open, C clawed, disc/nectary outside A, ovules in two rows; endotesta crystalliferous; 3' rbcL extension.

Chemistry, Morphology, etc. In Pentadiplandraceae, Brassicaceae and Tovariaceae the lateral sepals are initiated before the median sepal (Ronse Decraene 2002). For ovule type and the different mechanisms by which the ovule becomes campylotropous, see Boesewinkel (1990) and Bouman and Boesewinkel (1991), for bracteoles, see Ronse Decraene (1992). Ronse de Craene and Haston (2006) suggest a number of other characters that may be synapomorphies for this clade, including floral symmetry and embryo development. Note that nectary morphology and absence/presence/position is very variable in Brassicales outside this core group.

Phylogeny. Phylogenetic relationships in this core group of Brassicales have been partly resolved in a three-gene study by Hall et al. (2004). Ronse de Craene and Haston (2006) found that Emblingiaceae moved outside the group in a combined morphological-molecular study, but many data were missing for Emblingia in particular and its floral morphology is odd and poorly understood (see below). Ronse de Craene and Haston (2006) suggested that it might be sister to [Bataceae + Salvadoraceae], but noted that there was little support for this position.

EMBLINGIACEAE Airy Shaw   Back to Brassicales

Subshrub; plant hispid; mustard oils?; cork cambium deep-seated; cambium storying?; sclereids +; leaves ± opposite; flowers axillary, monosymmetric, resupinate, K connate, lobed, deeply divided adaxially, C 2, ?not clawed, abaxial, connate by epidermis, slipper-shaped, nectary abaxial, androgynophore curved abaxially; A 8, median members absent, 4 abaxial fertile, 4 adaxial staminodial, forming a torus, pollen with short colpi with rounded ends and bulging apertures, the adjacent exine being thickened; G [2-3], placentation axile, 1 basal ovule/carpel, stigma shortly lobed; fruit indehiscent, pericarp thin; seed arillate, testa thick; endosperm ?type, scanty, embryo color?, hypocotyl short; n = ?

1[list]/1: Emblingia calceoliflora. W. Australia (map: from FloraBase 2004).

• Emblingiaceae are low-growing herbs with axillary, ebracteolate and strongly monosymmetric flowers. The flowers are held upside down, the large, connate calyx is slit adaxially, there are two, abaxial, slipper-shaped petals (hence the specific epithet), and there is a curved androgynophore with an abaxially-positioned nectary at the base.

Chemistry, Morphology, etc. The plant dries yellowish. There has been considerable disagreement over the floral structure: is the flower resupinate or not? Is the hood petalline or not? Are there one or three carpels? I largely follow Melville's interpretation (in Erdtman et al. 1969), see also Mueller (1860). Detailed studies of all aspects of this plant are needed, nevertheless, its embryo is curved, its flowers monosymmetrical, and its nectary is between the petals and stamens, all features appropriate for a position around here.

For general information, see Kubitzki (2002d) and Ronse de Craene and Wanntorp (2009: stipules present, reduced).

Previous Relationships. Emblingia was included in Polygalaceae by Cronquist (1981) and Polygalales by Takhtajan (1997) based on what seemed to be floral similarities. Savolainen et al. (2000b) placed Emblingiaceae in Gentianales, a position that is not currently supported.

Pentadiplandraceae [Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]: ?

Evolution. The larvae of Chrysomelidae-Alticinae beetles are quite commonly to be found on members of this clade (Jolivet 1988). This is the core Brassicales of Ronse de Craene and Haston (2006).

PENTADIPLANDRACEAE Hutchinson & Dalziel   Back to Brassicales

Shrubs or lianes; ellagic acid?, tannins?; cork?; vessel elements with ? perforations; wood ?storied; nodes 3:3; mucilage cells +; stipules minute; inflorescence axillary, subcorymbose, flowers polygamous; K 5, valvate, C 5, connivent at enlarged, concave base, limb flat, short andogynophore/disc, staminate flowers: A 9-13, connective shortly produced, pistillode +; carpellate flowers: staminodes +, gynophore short, G [3-5]; G opposite sepals, placentation axile, ca 10 ovules/carpel in two ranks, ovule type?, style long, stigma shortly lobed; fruit a berry; 1 seed/loculus, coat with layer of white, wooly, elongated cells towards outside ["seed pubescent"]; embryo white; n = ?

1/?1: Pentadiplandra brazzeana. Tropical W. Africa (map: from Hall et al. 2004).

Chemistry, Morphology, etc. The fruit contains the sweet-tasting protein, brazzein. The plant does not dry dark. Are there supernumerary buds? There are bordered pits in wood fibres and mucilage cells in the leaf epidermis (Boodle, K, ms.). Ronse Decraene (2002) suggests that the stipules are large, but they are certainly not particularly big on the vegtative part of the plant. Embryologically - and in many other respects - Pentadiplandra is poorly known, although Ronse Decraene (2002) has described its floral anatomy; Ronse de Craene and Haston (2006) suggest that its floral morphology is close to the ancestral form of the core Brassicales. There are no marginal or placental strands in the ovary.

For general information, see Bayer and Appel (2002), for embryo color, Martin Cheek (pers. comm.)

Previous Relationships. Cronquist (1981) included Pentadiplandra in his rather broadly circumscribed Capparaceae, Takhtajan (1997) segregated it as a family.

[Gyrostemonaceae + Resedaceae] Tovariaceae [Cleomaceae [Capparaceae + Brassicaceae]]: ?

Evolution. The stem group age for this group is estimated to be 47-45 million years before present, the crown group age 42-33 million years before present (Wikström et al. 2001)

Chemistry, Morphology, etc. Nucellar tracheids have been reported in Capparaceae and Resedaceae, at least (Werker 1997). The wood anatomy of Brassicaceae and Resedaceae is rather similar (Schweingruber 2006). For stipules, see Weberling (2006).

Gyrostemonaceae + Resedaceae: hairs unicellular; styluli +; calyx persistent; seeds arillate.

Phylogeny. The composition of this clade and relationships within it are currently uncertain. Of the sampled Stixeae (ex Capparaceae) that come out around here, the Asian Tirania may be close to Gyrostemonaceae and the New World Forchhammeria may be closer to Resedaceae (Hall & Sytsma 2000, 2002; Hall et al. 2002), or both may be associated with Resedaceae (Hall et al. 2004: details of the relationship depend on the gene sequenced). Their flowers tend to be 3-, 5- or 6-merous, there is no differentiation between the two perianth whorls, and the placentation is axile (see also Kers 2002). Tirania has six sepals and petals and axile placentation. Forchhammeria has two carpels, as well as an irregular number of sepals (see Gyrostemonaceae), no petals, parietal placentation and one ovule/carpel; only one one ovule/fruit usually develops. The whole Stixeae (= Stixaceae Doweld) - and also Boscia - are Indo-Malesian climbers with successive cambia (Carlquist 1988) and are certainly out of place in Capparaceae (map: from Jacobs 1960).

GYROSTEMONACEAE Endlicher, nom. cons.   Back to Brassicales

Trees to shrubs; myrosin cells 0, tannins?; cork subepidermal; wood storied; petiole bundle arcuate; leave blades flat in bud, (stipules 0); plants usu. dioecious, inflorescence various; flowers small; P uniseriate, connate, 4-8-lobed or not, axis flattened, disc-like; staminate flowers: A 6-many, in 1 or more whorls around axis, centripetal, filaments ± 0, pollen tricolpate, ektexine spongy, undifferentiated; carpellate flowers: G (1 [2-)many], borne around axis in 1 (2) whorls, connate or not, when G 2, transverse, placentation axile-apical, 1 apotropous ovule/carpel, (styluli marginal), stigmas decurrent, large and spreading or not; fruit a dry or succulent schizocarp (achene; syncarp); endosperm copious, embryo color?; n = 14.

5[list]/18+: Gyrostemon (12). Australia, not in the north (map: see George 1982).

• Gyrostemonaceae are yellowish-drying (including the twigs) shrubs with rather small, often quite narrow but otherwise featureless leaves. The rather small flowers with a persistent, connate calyx (presumably; there is only a single perianth whorl) and many stamens and/or carpels clearly arranged in a whorl are quite distinctive.

Evolution. Gyrostemonaceae are wind-pollinated.

Chemistry, Morphology, etc. For gynoecial orientation, see Friedrich (1956), for pollen, see Tobe and Takahashi(1995), for additional information, see Goldblatt et al. (1976: general), Hufford (1996: floral development) and George (2002d: general).

RESEDACEAE Berchtold & J. Presl, nom. cons.   Back to Brassicales

Herbs (shrubby); idioblastic myrosin cells 0, tannins 0; cork?; no bordered pits in imperforate tracheary elements; leaf blade margins entire to pinnatifid, (stipules 0); flowers vertically monosymmetric, hypanthium short or 0, K ± valvate, (4-)6(-8), C valvate, (0, 2, 4-)6(-8), unequal, the adaxial largest, ligulate at junction of claw and limb, limb usu. ± fringed, disc esp. pronounced adaxially, (bipartite), almost petaloid; A 3-many from ring primordium and centrifugal, basally connate or not, (short gynophore +); G [(2) 3-6(-8)] (± free), opposite sepals or when 3, median member often adaxial, often open apical-adaxially, placentation parietal (axile), (1-)several (tenuinucellate) ovules/carpel; fruit with apical opening persisting between the styles (follicle; berry); (aril 0), endotestal cells cuboid, ± thickened, unlignified, exotegmic cells fibrous, lignified; n = 5-15.

3[list]/75: Reseda (68). Warm temperate and dry subtropical, esp. Mediterranean-Middle East-North African, also southern Africa, S.W. North America and S.W. China (all Oligomeris) (map: see Meusel et al. 1965; Hultén & Fries 1986; Martín-Bravo et al. 2009). [Photo - Flower]

• Resedaceae are yellowish-drying sometimes somewhat shrubby herbs with terminal, racemose inflorescences and rather small, monosymmetric flowers. The leaves are quite variable, although there are often small stipules. The petals are free and clawed; the adaxial petals are usually largest and the limb is often fringed. The extrastaminal disc/nectary is often conspicuous. The dry fruits often have an apical opening persisting between the styles (a quasi follicle) and the seeds are often arillate.

Evolution. The distribution of Oligomeris, native to both the Old and New Worlds, shows considerable disjunctions (Martín-Bravo et al. 2009).

Chemistry, Morphology, etc. Ochradenus has C 0, A many; G 3, the carpels are ultimately closed, and the fruit is berry-like - cf. Gyrostemonaceae (Hufford 1996); however, this genus seems to be derived from within Reseda (Martín-Bravo et al. 2007). The androecium of Reseda luteola may be in 3-4 whorls (for references, see Abdallah 1978), cf. again also Gyrostemonaceae. The appendages on the fruit are also described as being caruncles.

For stipules, see Weberling (1968), for general information, see Abdallah (1967), Abdallah and de Wit (1979) and Kubitzki (2002d), for floral development of Reseda lutea, see Leins and Sobick (1977), and for wood anatomy, see Carlquist (1998a) and Schweingruber (2006).

Phylogeny. Martín-Bravo et al. (2007) discuss the phylogeny and biogeography of the family; the topology of the tree suggests that just three genera should be recognised - [Caylusea [Sesamoides + Reseda]].

Synonymy: Astrocarpaceae A. Kerner

TOVARIACEAE Pax, nom. cons.   Back to Brassicales

Herbs to shrubs; glucosinolates not from phenylanaline or tyrosine, tannins?; cork?; no bordered pits in imperforate tracheary elements; leaves trifoliolate, stipules cauline or on leaf base; flowers (6-)8(-9)-merous, K free, stamens = and opposite sepals, gynophore short; G [(5) 6(-8)], alternating with K, placentation ± axile, many ovules/carpel in several ranks, micropyle zig-zag, funicle long, stigmas spreading; fruit a berry; exotestal cells ± enlarged, tanniniferous, walls thickened, endotestal cells small, exotegmic cells fibrous, walls reticulately thickened; endosperm thin, embryo color?; n = 14.

1[list]/2. Tropical America (map: see Hall et al. 2004). [Photo - Flower, Fruit]

• Tovariaceae are herbs that can be recognised by their trifoliate, stipulate leaves, terminal, racemose inflorescence, and 6-9-merous, polypetalous flowers with a short style and spreading stigmas.

Chemistry, Morphology, etc. The ovules are ± anatropous, but become campylotropous by the post-fertilisation development of the exotegmen (Boesewinkel 1990). For general information, see Appel and Bayer (2002).

Capparaceae [Cleomaceae + Brassicaceae]: sinapine, methyl glucosinolates, erucic acid [fatty acid] +, glucosinolates also from methionine [aliphatic glucosinolates]; stomatal myrosin cells 0, cisternae of endoplasmic reticulum organelle-like, etc.; cork also cortical; lateral wall pits of vessels vestured; nodes also 3<:3<; eglandular hairs simple, unicellular [?level]; leaves simple to palmately compound, blades usu. conduplicate, margins pinnately lobed to entire; flowers 4-merous, (vertically monosymmetric); K (2-)4(-6); A from 4 primordia, centrifugal, longer than the petals, filaments articulated, gynophore +, when 2 carpels, collateral (superposed, oblique), placental strands well developed, placentation parietal, many (tenuinucellate) ovules/carpel, micropyle zig-zag (endostomal), stigma lobed, subcapitate or not; K deciduous; seeds with invaginated coat, exotesta palisade or not, endotesta with inner walls ± thickened, ± thick-walled, endotegmen lignified (or not).   Back to Brassicales

Evolution. The divergence between Capparaceae and the [Cleomaceae + Brassicaceae] clade has been dated to ca 23 million years before present (Wikström et al. 2001), but this is in conflict with other estimates for ages in this clade, e.g. divergence between Capparaceae and Brassicaceae at ca 41 million years before present (Schranz & Mitchell-Olds 2006). Capparaceae are notably prominent in seasonally dry tropical forest (Pennington et al. 2009).

Pierid caterpillars (Pieridae-Pierinae - there are 840 species) are notably common on members of this group. For details of the interactions of butterflies and plants, see Courtney (1986) and Chew (1988) and references. Ca 1,000 species of these plants are susceptible to pseudoflower-forming rust fungi (Puccinia spp.) (Roy 1993, 2001); see especially Brassicaceae.

Chemistry, Morphology, etc. Campylotropy is by the inpushing of the chalazal bundle. True blue or red flowers are very rare in the whole group. The ventral carpellary bundles are fused and weakly developed (Ronse de Craene & Haston 2006). Rodman et al. (1996) list 11 possible apomorphies for this node.

The distribution of root hairs and of methyl glucosinolates, and variation patterns in seed coat anatomy are a little odd. Both Brassicaceae and Resedaceae have glucosinolates derived from elongated amino acid chains (Kjær 1973; esp. Fahey et al. 2001). Only Wasabia japonica in Brassicaceae has a glucosinolate similar to those in Cleomaceae and Capparaceae, while one aromatic glucosinolate of Cleomaceae and Capparaceae is also found in Resedaceae. Quaternary ammonium compounds, including betaines, are common in both Capparaceae and Cleomaceae, and also Boscia (see the [Resedaceae + Gyrostemonaceae] clade), but have not been detected in Pentadiplandra or Emblingia - or Buhsia (McLean et al. 1996).

Phylogeny. Capparaceae are sister to Cleomaceae + Brassicaceae; for further details of relationships see Hall and Sytsma (2000) and Hall et al. (2002). Vaughan and Whitehouse (1971) suggest that Brassicaceae differ from Capparaceae (inc. Cleomaceae) in that the latter have a testa that is only two (not three) cell layers thick, a persistent tegmen (rare) and a thicker endosperm (1 cell layer thick). Judd et al. (1994) provide a morphological phylogeny for Brassicaceae and Capparaceae sensu latissimo.

Classification. Although Cruciferae/Brassicaceae s. str., cabbage and mustard, have always been considered as one of the most natural plant families, their recognition makes Capparaceae s.l. (= Capparaceae s. str. + Cleomaceae) paraphyletic. So the alternatives are to have one family (Brassicaceae s.l.); three families; or two families, a Brassicaceae including Cleomoideae and a Capparaceae; the second option is followed here.

CAPPARACEAE Jussieu, nom. cons.   Back to Brassicales

Trees and shrubs (herbs, climbers); root hairs 0; pyrrolidine alkaloids +; petiole bundle annular or arcuate; sclereids +; stipules usu. minute; (inflorescence fasciculate); (flowers monosymmetric; K + C tube +), (K connate), C (0); A (1-)4-8(-many and centrifugal), pollen surface variously sculpted; G [2-12], when 2, transverse, (placentation axile; secondary septae +; style +); fruit a berry (transversely schizocarpic; septicidal); tegmen multiplicative, to 6 layers thick, exotegmen radially enlarged, sclerified, endotegmen with lignified bands on anticlinal walls; n = (7-)10(-15+); 6 bp insertion in ndhF gene.

16[list]/480: Capparis (250), Maerua (100), Boscia (37), Cadaba (30). Largely tropical (map: from Jacobs 1960; Wickens 1976; George 1982; Jalas & Suominen 1991; Culham 2007 [New World]). [Photo - Flower, Fruit.]

• Capparaceae are woody, the inflorescence is racemose, the flowers have a gynophore and often many stamens with long filaments, and the fruit is indehiscent.

Chemistry, Morphology, etc. Crateva has glands (?colleters) at the base of the lamina. Some Capparaceae have supernumerary buds and dry yellowish.

For some information on floral development, see Ronse Decraene and Smets (1997), and for general information, see Kers (2002).

Phylogeny. A paraphyletic Crateva is strongly supported as being sister to the rest of the subfamily; Capparis is probably diphyletic (Hall et al. 2002; Hall 2008). Hall (2008) discusses generic limits in Capparaceae, which are in need of substantial work; for example, New World Capparis will need a new name.

Previous Relationships. Forchhammeria and perhaps other Stixeae that used to be placed here are properly to be placed in or near Resedaceae (Hall et al. 2002, 2004)). Setchellanthus (see Setchellanthaceae) and Koeberlinia (Koeberliniaceae, both still Brassicales) also used to be included here.

Cleomaceae + Brassicaceae: herbaceous annuals (shrubs); inflorescence ± corymbose, (bracts foliaceous); C 4, clawed; A 6; G [2]; fruit septicidal, persistent placental strands + (0).

Chemistry, Morphology, etc. Some Cleomaceae and Brassicaceae have similar acylated anthocyanins (Jordheim et al. 2009). For foliaceous bracts, see Eichler (1878) and Prenner et al. (2009). Since Aethionema, with a more or less sessile gynoecium, is sister to all other Brassicaceae, similarities of Stanleya, etc., to Cleomaceae (e.g. herbaceous habit; long gynophore) are presumably parallelisms (Galloway et al. 1998); Stanleya, etc., form a clade well embedded in Brassicaceae. For floral development, see Leins (2000, and references).

CLEOMACEAE Horaninow   Back to Brassicales

Root hairs 0; petiole bundle(s) arcuate; leaves often palmate, (stipules +); bracts foliaceous (not); plant monoecious (Podandrogyne); flowers also monosymmetric, (androgynophore +), anthers linear, coiled at dehiscence, pollen surface variously sculpted, often spinulose; (fruit indehiscent); (seeds arillate); exotegmen cells radially elarged, sclerified, endotegmen cells with lignified bands on periclinal walls; n = ³9.

10[list]/300: Cleome (275: including Podandrogyne). Tropical and warm temperate, esp. America (map: see Wickens 1976; George 1982; Jalas & Suominen 1991; Culham 2007). [Photo - Inflorescence, [Flower.]

• Cleomaceae are herbaceous or shrubby plants with palmately compound leaves, the inflorescence is racemose, the flowers have four clawed petals, six stamens, and two carpels; the gynoecium has a gynophore, the stamens have long filaments, and the dehiscent fruit has a htin, persistent, loop-like woody placenta that remains on the plant after the fruit valves have fallen off.

Evolution. A duplication (hexaploid) of the genome in the family occured ca 20 million years before present (it was detected in Cleome spinosa: Schranz & Mitchell-Olds 2006). There are a few species of Cleome with C₄ photosynthesis, e.g. C. gynandra.

Chemistry, Morphology, etc. Note that in Cleomaceae the inflorescence may be a corymb, there are usually 6 stamens, etc., just like Brassicaceae - e.g. as in Podandrogyne (= Cleome) - also with orange flowers, 3-foliolate leaves and a gynophore.

For general information, see Kers (2002: in Capparaceae), for anther dehiscence, see Mitchell-Olds et al. (2005).

Phylogeny. For a phylogeny of Cleome and its immediate relatives, see Catalan et al. (2007) and Inda et al. (2008b). Relationships within Cleomaceae have rather little support, even if there are suggestions that Cleome itself is widely scattered on the tree (Hall 2008).

The small-flowered Dipterygium, placed in Capparaceae in a subfamily by itself by Kers (2002), is possibly to be included here. It has six stamens that are all equal in length, a filiform style, a winged, 1-seeded nut, and incumbent cotyledons; methylglucosinolates are recorded from the plant (Hedge et al. 1980).

Classification. Generic limits are unsatisfactory and will need attention.

Synonymy: Oxystylidaceae Hutchinson

BRASSICACEAE Burnett, nom. cons.//CRUCIFERAE Jussieu, nom. cons. et nom. alt.   Back to Brassicales

(Nortropane alkaloids +), methyl glucosinolates 0; roots lacking mycorrhizae; cork ?always deep-seated; (included phloem +); stomata anisocytic; hairs variously furcate; (leaves pinnately lobed), stipules 0; bracts 0 (foliaceous); floral development closed, (flowers disymmetric; monosymmetric); A (4), the two outer shorter than the four inner [tetradynamous], about as long as petals, lateral nectary lobes outside inner A, pollen trinucleate, surface often reticulate, gynophore 0 (+), commissural septum +, style often +, short, stigma commissural; seed folded, but no invagination of the coat, testa often mucilaginous, 3-layered, exotestal cells reticulately thickened on radial walls, endotesta lignified, palisade and/or with U-shaped thickenings or not, tegmen multiplicative, not persistent; chalazal endosperm cyst +, endosperm 1-layered; n = (4-)8(-13); duplication of PHYB -> PHYD gene; sporophytic self-incompatibility system present.

338[list]/3710 - two groups below. World-wide, esp. N. temperate (map: from Vester 1940; Hultén 1971). [Photos - Collection].

Aethionemeae Al-Shehbaz, Beilstein & E. A. Kellogg

Plant glabrous; nortropane alkaloids +; 3 veins on petal claws, median nectaries 0, (1-)2-4(-8) ovules/carpel; fruit angustiseptate; n = 7, 8, 11, 12, 14...

1-2/70. The Mediterranean and Europe to Afghanistan (map: from Mark Menke, pers. comm.). [Photo - Flowers.]

The Rest.

(Eglandular hairs branched, stellate, T-shaped); genome duplication.

338/3710: Draba (365), Cardamine (200), Erysimum (225), Lepidium (230), Alyssum (195), Arabis (120), Boechera (ex Arabis - 110), Physaria (105: inc. Lesquerella), Rorippa (85), Heliophila (80), Isatis (80), Noccaea (80), Thlaspi (55), Biscutella (55), Matthiola (50), Descurainia (50), Hesperis (45), Sisymbrium s. str. (45: only Old World). World-wide, esp. N. temperate (but less E. North America, and even more so humid lowland tropics). [Photo - Flowers, Flowers, Fruit.]

• Most Brassicaceae are herbs, and a number of taxa have distinctive small, branched, eglandular hairs. The ebracteate inflorescence is corymbose, the flowers have four, clawed petals (the alternate name 'Cruciferae' for this family is taken from the cross-like arrangement of these four petals), six stamens with relatively short filaments (so the anthers are included), the gynoecium has two carpels and a short style, and the dehiscent fruit has both persistent, almost woody placental strands and a membranous false septum.

Evolution. Stem group Brassicaceae have been estimated to be 22-18 million years old (Wikström et al. 2001), some 41 million years old (Schranz & Mitchell-Olds 2006), or some 50 million years old, with divergence of Aethionemeae from the rest ca 40 million years before present (Al-Shehbaz et al. 2006). Recent estimates suggest an age of (45-)19(-1) million years before present for stem group Brassicaceae, (35-)15(-1) million years for crown group diversification, and (28-)11(-1) milion years for diversification of the family minus Aethionema (Frantz et al. 2009: the figure are 95% HPD [high probability distribution]). Initial diversification was in the Old World, perhaps in the Irano-Turanian region (Frantz et al. 2009 and references), and there there seems to have been a rather rapid radiation of the lineages that encompass most of the diversity of the family today (Beilstein et al. 2006; Al-Shehbaz et al. 2006; Bailey et al. 2006a, b); the stem clade may have may have been adapted to warm and humid conditions in the east Mediterranean area (Frantz et al. 2009).

Biogeographical histories within the family can be complex, with chloroplast and nuclear genomes of Californian and African ancestry variously combined in Antipodean Lepidium (Dierschke et al. 2009). Kiefer et al. (2009) discuss the phylogeographic structure of the speciose largely North American Boechera; divergence seems to be a Pleistocene phenomenon with considerable hybridization and apomixis. Draba is a young polyploid complex in which there is considerable geographical structure in the distribution of diploids and polyploids (Jordon-Thaden & Koch 2008). Indeed, there has been extensive hybridization and genome duplication in the family (see also below) at various times; for example, there is extensive polyploidy and hybridization in Cardamine (Lihová & Marhold 2006).

Duplication of the whole genome seems also to have occured fairly soon after the split from the Capparaceae and has been dated to 34-25 million years before present (Vision et al. 2000; Blanc & Wolfe 2004), perhaps after the divergence of the Aethionema clade (Blanc et al. 2003; de Bodt et al. 2005; Schranz & Mitchell-Olds 2006; Frantz et al. 2009); see also the findings of Galloway et al. (1998) on the pattern of duplication of the ADC (arginine decarboxylase) gene. There is also further extensive genome duplication within the family (Kellogg & Bennetzen 2004), and this has happened more than once (Vision et al. 2000; Blanc & Wolfe 2004; Blanc et al. 2007; Lysack et al. 2007); "diploid" species like Brassica oleracea, with n = 9, are hypothesised to be ancestral hexaploids (Mitchell-Olds et al. 2005). Jaillon and Eury et al. (2007, and references) suggest that Arabidopsis has had two whole genome duplications, although there is some discussion as to exactly how many bouts of duplication have occured. There has been extensive transposition of genes in the Arabidopsis genome - between 1/4 and 3/4 of the genes may have moved some time after the origin of the order (Freeling et al. 2008). The origin of a trnF pseudogene has been associated with a duplication in the common ancestor of the Halimolobus + Boechera + Cardamine clade, some 21-16 million years before present (Koch et al. 2005). Mathews and McBreen (2008) discuss the duplication of PHYBgene. It has been suggested that n = 8 is ancestral in the family, with subsequent extensive genome rearrangement (Lysack et al. 2006). Karyotype evolution in the family is of considerable interest. One major clade (lineage I) has x = 8, another clade that includes lineage II has x = 7, but with subsequent increase (Mandáková & Lysack 2008).

According to Medve (1983), any mycorrhizal associations in the roots of Brassicaceae are at best weak and facultative, and although arbuscular mycorrhizae have recently been reported from Thlaspi, it is doubtful if an effective symbiosis results (Regvar et al. 2003). Indeed, glucosinolates can depress vesicular-arbuscular mycorrhizal activity, a possible element in the invasive capabilities of Alliaria petiolata in parts of North America (Wolfe & Klironomos 2005). As is well known, glucosinolate diversity in the family is considerable, as is variation in content between different species in the same community. The presence of particular glucosinolates may induce oviposition by Pieris butterflies, whether or not the crucifer with that glucosinolate is edible or kills the caterpillar (Chew 1979, see also 1988); parasitoids are also involved, and the complexity of the interactions increases exponentially (Fatouros et al. 2008). Caterpillars of cabbage white butterflies (Pieris spp.) and the diamond-back moth (Plutella xylostella) are able to convert the glucosinolates that are produced when they damage plant tissue as they eat into non-toxic substances such as nitriles (Wittstock et al. 2004; Ratzka et al. 2002 - see also introduction to Brassicales). Insects such as the cabbage aphid, Brevicoryne brassicae, sequester the glucosinolates, in this case even producing its own myrosinases that break the glucosinolates down and so helping to deter predators (Kazana et al. 2007).

The association between the pseudoflower-forming Puccinia rust and host has been much studied in Brassicaceae (Roy 1993 [particularly fine photograph], 2001; Ngugi & Scherm 2006). Insects come to the pseudoflowers, attracted both by the colouration of the leaves and floral fragrances. These latter differ from those of both of the crucifer host and the other plants in the general area, containing i.a. constitutively-released isothiocyanates (Raguso & Roy 1998). They pick up the rich fructose nectar secreted by the fungus along with the fungal spermatia in the nectar; they then fly to another "flower", deposit the spermatia and pick up more. On combination of spermatia of the appropriate mating types, diploid aecia are produced, the "flower" stops producing nectar, and the petals, i.e. the leaves, become green.

Arabidopsis thaliana can take up nitrogen in an organic form as amino acids (Hirner et al. 2006), although the general significance of this is unclear. Most of the nickel and zinc hyperaccumulators known in flowering plants occur in Brassicaceae (Baker & Brooks 1989; Grennan 2009 for a review); Freeman et al. (2009) suggests that selenium, accumulated by Stanleya pinnata, protects the plants against herbivory by prairie dogs.

Chemistry, Morphology, etc. For tocopherols in Brassicaceae, see Goffman et al. (1999), Badami and Patil (1981) for seed fatty acids, and Harborne (1999, but sampling) for distinctive sulphur-containing phytoalexins. The border cells of the root cap dissociate in rows (Driouich et al. 2006); other Brassicales should be examined for this character. There are rarely glandular stipules in the inflorescence and elsewhere (see Weberling 2006 for a summary, also Bowman 2006). The flowers of Iberis amara are monosymmetric, although the corymbose inflorescence is functionally more like a single polysymmetric flower (Busch & Zachgo 2007). there is a long-standing controversy in the family concerning the six stamens: did they arise by dédoublement or by reduction? Brassicaceae have tryphine, in which some constituents of the disorganised tapetal cells are still visible, covering the pollen grains, not pollenkitt, as in other angiosperms (Pacini & Hesse 2005), although details of the distribution of this feature are unclear. Another controversy concerns carpel number. The commissural stigmas of Brassicaceae have been supposed to indicate that the gynoecium is basically 4-carpellate. Although such stigmas are notably common in groups with parietal placentation, there may be normally oriented bundles outside the inverted placental ventral carpellary bundle in Crataeva religiosa, perhaps indicative of an original 4-carpellate condition with axile placentation (Dickison 2000, but cf. Brückner 2000). Note. however, that taxa with four carpels are uncommon in Brassicales. The chalazal endosperm cyst may be involved in the movement of metabolites into the developing seed, there being transfer cells around it (Brown et al. 2004). Bowman (2006) discusses morphology in general in the context of comparative developmental genetics.

See Vaughan and Whitehouse (1971) and Bouman (1975) for ovules and seed coat, Erbar and Leins (1997a, b) for floral development, and Al-Shehbaz (1984), Appel and Al-Shehbaz (2002), Koch et al. (2003), Hurka et al. (2005) and Mitchell-Olds et al. (2005) for general information and references. See also Khoul et al. (2002: testa surface morphology), Khalik et al. (2002 and references) for pollen morphology; Brown et al. (2004) for the endosperm cyst (Aethionema not sampled, cyst probably not in in Cleome, at least). Lysack et al. (2005) discuss chromosome triplication in Brassiceae and Lysack et al. (2009) the evolution of genome size, which is not particularly linked with chromosome number, while Warwick and Al-Shehbaz (2006) summarize chromosome numbers. See Grubb and Abel (2006) for glucosinolate metabolism; Brock et al. (2006) for nortropane alkaloids (in both Aethionema and Cochlearia, i.a.); Beilstein et al. (2006) for trichome evolution; Koch and Kiefer (2006) for a summary of biogeographic studies; and Bernadello (2007) for nectary variation. Schweingruber (2006) gives details of phloem and xylem anatomy.

Phylogeny. Of late, substantial progress has been made in providing a phylogenetic framework for the family (e.g. Koch et al. 2001: Koch 2003; Beilstein et al. 2006) and realigning taxa accordingly. Aethionema, a variable but poorly known genus with angustiseptate fruits, is sister to the rest of the family (e.g. Zunk et al. 1996, 1999; Koch et al. 2001; Beilstein et al. 2006). For the limits of Aethionema, see Khosravi et al. (2008). However, the relationships between many of the tribes are still unclear (Beilstein et al. 2006; Al-Shehbaz et al. 2006; Bailey et al. 2006a, b; Franzke et al. 2009).

Warwick and Sauder (2005) found a monophyletic Brassiceae that needed but little adjustment from its classical delimitation, but "well-known" genera such as Brassica, Diplotaxis, and Erucastrum were polyphyletic; as they noted, this should affect how breeders went about their business. Although genera such Draba and Lepidium are monophyletic or largely so on both morphological and molecular grounds, others, such as Brassica, are not (e.g. Mitchell-Olds et al. 2005 and references). Although Arabidopsis thaliana is perhaps the most important model vascular plant in biology, the limits of the genus Arabidopsis are only now being established (see Clauss & Koch 2006 for a discussion of its immediate relatives). Mummenhoff et al. (1997), Koch and Mummenhoff (2001) and Meyer (2003) discuss generic limits surrounding Thlaspi, a polyphyletic genus; the sometimes invasive Alliaria petiolata, with very different fruit morphology, is to be placed around here. Sisymbrium s. str. is restricted to the Old World, the New World taxa being unrelated and mixed in with Theylpodieae (Warwick et al. 2002, 2006a). For a study of Alysseae and related tribes, see Warwick et al. (2008), of Schizopetaleae and Thelypodieae, Warwick et al. 2009), of Matthiola, Jaén-Molina et al. (2009), of Boechera and relatives, Kiefer et al. (2009a, b), of some Asian taxa, German et al. (2009: ITS), and of Iranian Brassicaceae, see Khosravi et al. (2009).

See also Price et al. (1994), Galloway et al. (1998), and Warwick et al. (2007) for other phylogenetic studies.

Classification. in the past, goth generic and tribal limits have tended to be based on single characters like fruit shape (reified as fruit "types") and embryo curvature and have turned out to be something of a nightmare (e.g. Mummenhoff et al. 1997; Al-Shehbaz et al. 2006). There has been parallel or convergent evolution of just about all the morphological features used to distinguish genera (Koch 2003; Al-Shehbaz et al. 2006; Bailey et al. 2006a, b; Beilstein et al. 2008). Hence the major disagreements over generic limits (see above). Although "intergeneric" hybridisation is quite common (see summary in Warwick et al. 2006), this is of uncertain significance given these problems with generic circumscriptions. However, Al-Shehbaz et al. (2006) recognise 25 monophyletic tribes based on clades recognised in molecular studies in which they place 260 of the 338 genera of the family (see also Beilstein et al. 2008). Genera were often based on fruit and embryo differences Thelypodieae, with their exserted stamens, gynophore, etc., appear to be similar to Capparaceae and to have a plesiomorphic morphology, but are in fact derived within Brassicaceae.

Warwick et al. (2006b) provide a species checklist for the family.

Synonymy: Drabaceae Martynov, Erysimaceae Martynov, Raphanaceae Horaninow, Sisymbriaceae Martynov, Stanleyaceae Nuttall, Thlaspiaceae Adanson