EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline; primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, xylem exarch; shoot apical meristem complex; arbuscular mycorrhizae +; stem with ectophloic eustele, endodermis 0, xylem endarch; 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 ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, mono[ana]sulcate, pollen exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development endo/exosporic, gametes two, with cell walls; 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, 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 via tyrosine pathway, 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 sieve plate, companion cells from same mother cell that gave rise to the tube, the sieve tube with P-proteins; nodes unilacunar; stomata with ends of guard cells level with aperture, paracytic; leaves with petiole and lamina [the latter formed from the primordial leaf apex], development of venation acropetal, 2ndary veins pinnate, fine venation reticulate, vein endings free; flowers perfect, polysymmetric, parts spiral [esp. the A], free, numbers unstable, P not differentiated, outer members not enclosing the rest of the bud, A many, development centripetal, 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, pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous, endexine compact, lamellate only in the apertural regions, pollen tube elongated, with callose plugs, penetrating between cells, growth rate moderate, siphonogamy occuring, nectary 0, G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, stigma ± decurrent, wet [secretory]; P deciduous in fruit; seed exotestal; 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; 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/PHYC gene pairs.

Possible apomorphies 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. Furthermore, details of relationships among gymnosperms will affect the level at which some of these characters are pegged.

NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessels +, elements with scalariform perforation plates; pollen tectate-columellate, tectum reticulate [perforated]; nucleus of egg cell sister to one of the polar nuclei; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

PROTEALES [TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]]: ?

TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.

BUXALES [GUNNERALES + CORE EUDICOTS]: ?

GUNNERALES + CORE EUDICOTS: Ellagic and gallic acids common, cyanogenesis via phenylalanine, isoleucine or valine pathways; micropyle?; PI-dB motif +, small deletion in the 18S ribosomal DNA common.

CORE EUDICOTS: Root apical meristem closed; flowers rather stereotyped: 5-merous, parts whorled, K and C distinct, K with 3 traces, A = 2x K, internal to the C whorl, (numerous, but then often fasciculate and/or centrifugal), pollen tricolporate, (nectary disc +), [G 5], [3] also common, compitum +, placentation axile, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; euAP1 + euFUL + AGL79 genes [duplication of AP1/FUL or FUL-like gene], PLE + euAG [duplication of AG-like gene: C class], SEP1 + FBP6 genes [duplication of AGL2/3/4 gene].

SAXIFRAGALES [VITALES + ROSIDS]: Stipules +.

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.

ROSID I: Endosperm scanty.

CUCURBITALES + FAGALES [FABALES + ROSALES]:   Back to Main Tree
(N-fixing by root-dwelling associates [usu. the actinomycete Frankia]); tension wood +; stipules cauline; seed exotestal; embryo large.

Fabales + Rosales: ?

Given that basal branchings within neither Fabales nor Rosales are well understood, making suggestions as to synapomorphies for the two orders together and individually is difficult.

FABALES Bromhead  Main Tree, Synapomorphies.

Ellagic acid 0; wood often fluorescing; nodes?; styloids +; carpels free, embryo green. - 4 families, 754 genera, 20055 species.

Fabales contain ca 9.6% eudicot diversity (Magallón et al. 1999), of which the bulk is made up of Fabaceae. Wikström et al. (2001) date the origin of the clade to 94-89 million years before present, diversification beginning 79-74 million years before present.

Although styloids are reported from Surianaceae, Quillajaceae and Fabaceae, details of their distribution within Fabaceae are unclear; they are certainly quite common in Faboideae (Lersten & Horner 2005), apparently less so in the rest of the family. There may be some palynological features loosely holding this group together. Quillajaceae and some Surianaceae have exine protruding at the apertures, and these and Fabaceae-Cercideae (although perhaps derived within that group?) have striate pollen (Banks et al. 2003; Claxton et al. 2005). It would be nice to know if Surianaceae or Quillajaceae had starchy endosperm, and more details of their chemistry are needed. Note the variation in nodal anatomy within the order. Despite the floral differences between Polygalaceae and Fabaceae, there are some developmental similarities between the two (Prenner 2004d).

A rather unexpected group, but it is quite strongly supported - see Morgan et al. (1994), Källersjö et al. (1998), etc. However, Hilu et al. (2003) find Larrea (Zygophyllaceae) to be weakly associated with Fabaceae, the only member of Fabales included in their rbcL analysis. Persson (2001) suggested the relationships [Polygalaceae [Surianaceae [Quillajaceae + Fabaceae]]], but there was little support for this (see the tree in versions 1-7). Forest et al. (2002) found weak support for the topology [Quillajaceae [Fabaceae [Surianaceae + Polygalaceae]]], and Banks et al. (2008) suggest that there is strong support for the relationship [Quillajaceae [the rest]] (see the tree here), although Wojciechowski et al. (2004, but sampling) suggested the possibility of a [Surianaceae + Quillajaceae] grouping... The rpl22 gene is in the nucleus in Polygalaceae and Fabaceae (i.e. is absent from the chloroplast), but the condition in the rest of the order is unknown (J. J. Doyle et al. 1995). Many Fabaceae-Faboideae have lost the rps16 gene, and it is also absent from Polygala (Downie & Palmer 1992: again, sampling).

Includes Fabaceae, Polygalaceae, Quillajaceae, Surianaceae.

Synonymy: Cassiales Horaninow, Polygalales Dumortier, Quillajales Doweld, Surianales Doweld - Fabanae Reveal, Polygalanae Doweld - Polygalopsida Endlicher

QUILLAJACEAE D. Don   Back to Fabales

Small evergreen tree; saponins, proanthodelphinidin, flavone C-glycosides +; storying?; nodes 1:3; petiole bundles arcuate, no pericyclic fibers; hairs warty, leaves spiral, conduplicate, margins toothed [hydathodal?], stipules petiolar; inflorescence terminal, cymose; hypanthium +, K valvate, nectary on lower half of K, C contorted, spathulate, clawed, A 5 opposite K above nectary + 5 opposite C below nectary, pollen striate, G becoming [5], opposite K, ?micropyle, several pleurotropous ovules in two marginal rows/carpel, stigmatic zone elongated along styles; fruit strongly asymmetrically lobed, follicular, opening down both surfaces of the lobes, K moderately accrescent; seeds winged, 3 outer testa layers thickened, sclerotic, tegmen disintegrating; endosperm type?, cotyledons investing radicle, conduplicate; n = 14, 17.

1/3. Temperate South America (Map: from Donoso Z. 1994; Culham 2007). [Photo - Flower, Fruit.]

• Quillajaceae are vegetatively rather undistinguished with their spiral, serrate, stipulate leaves, although the conspicuous teeth appear to be hydathodal. They may be readily recognised by their remarkable flowers in which the antesepalous stamens are borne on the outer edge of the disc some way up the sepals and the antepetalous stamens are near the base of the ovary. The petals are clawed and the strongly lobed fruits open down both the inner and outer surfaces of the lobes and contain winged seeds.

The leaves are amphistomatous. The flowers of Quillajaceae, with their distinctive positioning of nectary and androecium, may be interpreted as having a hypanthium. Development of the androecium is unidirectional and is rather like that of Fabaceae (Bello et al. 2007). The carpels are definitely connate axially, but are largely free laterally, cf. earlier versions of this site. There appear to be only three traces to each carpel, although Sterling (1969) noted that there were also "intermediate" bundles.

Quillaja was included in Rosaceae as part of Quillajoideae (Takhtajan 1997) or as Spiraeaoideae-Quillajeae (Robertson 1974: n = 17). It is indeed superficially similar to the South American Kageneckia, but wood anatomical data, etc., suggest that it should be removed from Rosaceae (Lotova & Timonin 1999; cf. Zhang 1992).

See also Hegnauer (1973, 1990, as Rosaceae) for chemistry, Sterling (1969) and Kania (1973) for gynoecial morphology, Lersten and Horner (2005) for vegetative anatomy, particularly styloids, Kubitzki (2006b) for a general account, and Bello et al. (2007) for floral development. Aronson 7897 (anatomy, embryo).

Fabaceae [Quillajaceae + Polygalaceae]: ?

FABACEAE Lindley, nom. cons.//LEGUMINOSAE Jussieu, nom. cons. et nom. alt.   Back to Fabales

Trees to annual herbs; lectins [hemagglutinins] and gums esp. in seeds, 5-deoxyflavonoids, Cglycosylflavonoids, pinitol [cyclitol] +; cork also in outer cortex; cambium storied; secretory cells common, sieve tube plastids with protein crystals (and/or starch, or simply starch); nodes 3:3; cuticle wax platelets as rosettes; stomata various; branching from previous flush; hairs often uniseriate (mesifixed); leaves (opposite), pari- or odd-pinnately compound (palmate, simple), leaflets often pulvinate, (glandular-punctate), stipellate or not, opposite (alternate), conduplicate, (margins lobed, toothed; 2ndary veins palmate); inflorescence racemose; flowers (3-)5(-6)-merous, hypanthium +, K initiation helical, odd C member adaxial, C clawed, A (2-)10(-many), G 1, stipitate, several serial ovules/carpel, micropyle zig-zag, styles long, (hollow), stigma expanded or not, wet; fruit follicular, dehiscing abaxially also, exotesta palisade, linea lucida separating much thickened outer anticlinal walls from the rest, mesotesta of stellate cells, (seed coat undistinguished), tegmen crushed; (thick-walled endosperm with galactomannans [Schleimendosperm]), chalazal haustorium + [?level]; cotyledons investing radicle; rpl22 gene absent.

730/19400 - discussed in four groups below. World-wide.

1. Cercideae

Trees to lianes; leaves apparently simple, bilobed or not; funicle?; n = 7, etc.

4-12/265: Bauhinia (250: for generic limits, see Sinou et al. 2007). Pantropical (temperate) (Map: from Meusel et al. 1965; Sales & Hedge 1996). [Photo - Bauhinia]; [Photo - © D. Kimbler - Cercis]

The flowers of Cercis are only superficially similar to those of Faboideae (Tucker 2002a). Hesse (1986) noted that both Bauhinia and Cercis - and Caesalpinia and Delonix - had pollen-connecting threads made up of something other than sporopollenin.

Synonymy: Bauhiniaceae Martynov

"Caesalpinioideae" + Mimosoideae + Faboideae: (N-fixation); (non-protein amino acids, esp. in seeds, +); vestured pits +(0); (fruit a drupe, samara, schizocarp, etc.); hour-glass cells [below palisade exotesta] +.

2. "Caesalpinioideae" Candolle

Shrubs or trees (herbs); (N-fixing, rhizobia remain in infection threads), often with ectotrophic mycorrhizae; non-protein amino acids +; sieve tube plastids also with fibres; leaves bicompound or not; (G adnate to side of hypanthium), ovules usu. campylotropous, outer integument with vascular strand; aril + (0), funicle long and thin to stout and thick, (pleurogram [area of cells with a deep-seated linea lucida] +); (seed with amyloid).

160[list]/1930: Senna (350: enantiostylous; bracteoles 0; A porose, three morphs, 3 adaxial staminodes, 4 middle, buzzed, 3 abaxial [longer] for pollination - see Marazzi et al. 2006 for a phylogeny; Marazzi & Endress 2008 for floral development), Chamaechrista (265: herbaceous; nodules!; enantiostylous; A two morphs in different whorls, anthers with velcro line), Cassia s. str. (A three morphs, with curved filaments, anthers with slits or basal pores); Caesalpinia (100: ?polyphyletic; abaxial sepal may be colorful and look like a keel). Predominantly tropical, esp. Africa and America. [Photos - Collection]

Extrafloral nectaries are rare, or are represented by tufts of hairs (Pascal et al. 2000); however, they characterise a major clade within Senna, and it has been suggested that they are a "key innovation" involved in plant defence and in the diversification of that clade (much more speciose than its sister taxon, see Marazzi et al. 2006). Asymmetry (enantiostyly) is likely to have been acquired once within Senna, although also subsequently lost.

Detarieae and Amherstieae have amyloid in their cotyledons, x = 12 (Hegnauer & Grayer-Barkmeijer 1993); amyloid is also found in Sclerolobieae (?different classifications?: see Kooiman 1960). Detarieae are well known for showing extensive loss of petals and/or stamens, or increase in the latter (Tucker 1992b and references); many taxa have crater-like glands on the abaxial surfaces of the leaflets, secrete resin, secretory canals in the stem, caducuous stipules and bracteoles, etc. (Redden & Herendeen 2006; morphological phylogenetic analysis; Fougère-Danezan et al. 2007: molecular study, characters of the group). The resins produced by Detarieae contain distinctive bicylic diterpenes, possibly an apomorphy for Detarieae (Fougère-Danezan et al. 2007). Umtiza is excluded from Detarieae, and forms a clade with taxa like Gleditsia, Gymnocladus and Ceratonia, several of which are dioecious and have smallish, greenish flowers sometimes with a poorly differentiated calyx and corolla - not plesiomorphic features (Herendeen et al. 2003a; see also Forest et al. 2007b).

For information on fruits and seeds, see Gunn (1991), for anatomy, see Gasson et al. (2003), and for additional information on relationships in caesalpinioid legumes, see Herendeen et al. (2003b) and Lavin et al. (2005).

Synonymy: Caesalpiniaceae R. Brown, Cassiaceae Vest, Ceratoniaceae Link, Detariaceae Hess

3. Mimosoideae Candolle

Shrubs or trees (herbs); N-fixing common; albizziine [non-protein amino acid] +; sieve tube plastids also with fibres; (septate fibers +; aliform axial parenchyma); rays usu. <20 cells high; leaves often bicompound, extrafloral nectaries common; flowers of inflorescence often develop together, bracteoles 0; flowers rather inconspicuous, polysymmetrical, hypanthium often 0, K usu. connate, valvate (imbricate), C usu. connate, valvate, odd member abaxial, claws 0, A often connate, polyads common, stigma (dry - one record), cup-shaped, (peltate); (aril +), funicle long, thin, testa with vascular strand, pleurogram + (0), linea fissura [fine line delimiting pleurogram] common.

82[list]/3275: Acacia s. str. (960: the old subgenus Phyllodinae), Mimosa (480: some have sensitive leaves), Inga (350: see Pennington 1997 for a monograph, Richardson et al. 2001b for diversification), Calliandra (200: pollen in polyads and with an associated mucilaginous body - Greissl 2006, cf. Teppner 2007), Vachellia (161: the old Acacia subgenus Acacia), Senegalia (85: the old Acacia subgenus Aculeiferum), Prosopis (45: for a phylogeny, see Catalano et al. 2008), Pithecellobium (40: some polycarpellate, but secondary; red and black seeds). Esp. tropical and warm temperate, esp. Africa and America (Map: from Vester 1940; Maslin et al. 2003). [Photos - Collection]

For floral development, see Gemmeke (1982); the androecium may be centripetal when borne on five main primordia. Prenner (2004b) notes the distinctive cochlear-descending calyx aestivation, helically-initiated androecium, etc., of Calliandra s. str., rather isolated within Mimosoideae; for polyads, anther dehiscence, etc., see Teppner (2007) and Teppner and Stabentheiner (2007) and references. Luckow et al. (2005) discuss variation in flower and seed in the clade.

Some ex-caesalpinioids (e.g. Dimorphandra) with small flowers in spikes or panicles may have to be included in Mimosoideae (Wojciechowski 2003), to which they show considerable similarity in wood anatomy (Evans et al. 2006), and/or Mimosoideae reduced to a tribe (Luckow et al. 2003). Ingeae are embedded in Acacieae or vice versa (e.g. Clarke et al. 2000; Robinson & Harris 2000; Miller & Bayer 2000, 2001; Luckow et al. 2003; Jobson & Luckow 2007; Brown 2008). The old Acacia subgenus Acacia, which includes the bull's horn acacias, seems to be monophyletic, but Acacia s.l. is polyphyletic. As Maslin (2001) noted sadly of the 955 or so species then placed in Acacia for the Flora of Australia treatment, "we are obliged to present the flora treatment [i.e., everything in the one genus] in the absence of a more meaningful classification". However, maybe things will change (Maslin et al. 2003) - the argument now is over what names to call the bits into which Acacia s.l. is to be divided (see above). Murphy et al. (2000, 2003) and Miller et al. (2003) discuss the phylogeny of Acacia s. str., and Miller and Bayer (2003) that of Vachellia and Senegalia. Siegler (2003) summarized the phytochemistry of the complex, Evans et al. (2006) detailed wood anatomy, and Kergoat et al. (2007) noted what bruchids had to say about systematics of Acacia s.l.; see also Muelleria 26(1). 2008, a special issue on Acacia, and also World Wide Wattle website.

Synonymy: Mimosaceae R. Brown

4. Faboideae Rudd, Papilionoideae Jussieu, nom. alt.

Herbs, vines (lianes, trees, shrubs); N-fixing common; isoflavonoids [pterocarpans and isoflavans], prenylated flavonoids, pyrrolizidine, indolizidine, and quinolizidine alkaloids +; (cork deep seated); sieve tubes with spindle-shaped non-dispersive protein bodies; (nodes 1:1); leaves once compound, palmate or pinnate; K with unidirectional initiation, ?hypanthium, adaxial C external, A usu. connate [e.g. 9 + 1], ovules usu. campylotropous; (aril +), pleurogram 0, counter palisade + or 0, hilum often with tracheid bar [group of tracheids just below surface of hilum]; embryo with well-developed suspensor [?not the basal condition], curved, cotyledons accumbent, not investing radicle, cotyledon areoles common, (starch in embryo [inc. Swartzieae]).

476[list]/13855: Astragalus (2400-3270: IRLC), Indigofera (700: aff. MILL, mesifixed hairs), Crotalaria (700: GEN), Mirbelia s.l. (450: MIRB, see Crisp & Cook 2003a, b), Tephrosia (350: MILL), Desmodium (300: MILL), Aspalanthus (300: GEN), Oxytropis (300: IRLC), Adesmia (240: DAL), Trifolium (240: IRLC), Rhynchosia (230: MILL), Lupinus (200: palmate leaves, pollen extruded as threads - for Andean diversification, see Hughes & Eastwood 2006), Aeschyomene (160: DALB), Hedysarum (160: IRLC), Lathyrus (160: IRLC), Vicia (160: IRLC, pollen presented on stigmatic brush), Dalea (150: DALB), Eriosema (150: MILL), Lotononis (150: GEN), Millettia (150: MILL), Vigna (150: MILL), Swartzia (140: SWAR)), Daviesia (135: MIRB), Lonchocarpus (MILL), Machaerium (130: DALB), Onobrychis (130: IRLC), Ormosia (130: unplaced), Lotus (inc. Coronilla: 125: ROB, for floral and inflorescence morphology esp. in Loteae, see Sokoloff et al. 2007), Lonchocarpus (120: MILL), Erythrina (110: MILL), Gastrolobium s.l. (110: MIRB), Mucuna (105: MILL), Pultenaea (100: MIRB, for limits, see Orthia et al. 2005), Genista (90: GEN), Medicago (inc. Trigonella, 85: IRLC), Swainsonia (85: IRLC), Caragana (75: IRLC), Jacksonia (75: MIRB - see Chappill et al. 2007 for a revision), Ononis (75: IRLC, see Liston 1995), Zornia (75: DALB), Argyrolobium (70: GEN), Arachis (70: DAL - see Krapovickas & Gregory 2007 for a revision), Brogniartia (65: GEN), Cytisus (65: GEN), Bossiaea (60: MIRB), Canavalia (60: MILL), Clitoria (60: MILL), Dolichos (60: MILL), Galactia (60: MILL), Phaseolus (60: MILL, for phylogeny, see Delgado-Salinas et al. 2006), Sesbania (60: ROB), Derris (55: MILL), Trigonella (55: IRLC), Lessertia (50: IRLC), Psoralea (50: MILL), Sophora (50: GEN). Esp. (warm) temperate, but world-wide (Map: from Vester 1940; Meusel et al. 1965; Hultén 1971). [Photo - Flower, Fruit, Collection.]

The pattern of initiation of the sepals is variable, by no means always being unidirectional (Prenner 2004a). The flowers of some Amorpheae have a stemonozone rather than a hypanthium (McMahon & Hufford 2002).

For the possible mode of action of the distinctive spindle-shaped non-dispersive protein bodies (= forisomes), found commonly in Faboideae, in blocking the pores of the sieve plates when turgor pressure changes, see Knoblauch et al. (2001); the protein bodies change shape depending on the concentration of Ca²⁺ ions (Peters et al. 2007). Cytisus forms a well-known graft hybrid with Laburnum (+ Laburnocytisus; see Herrmann 1951 for another example); the epidermis alone is Cytisus tissue, and any seeds, being derived from cells from deeper layers, will give Laburnum plants.

There has been the loss of the 25kb chloroplast inverted repeat in many Faboideae; this characterises a largely temperate, epulvinate, herbaceous and very speciose group, although Wisteria is also a member of this clade (the IRLC - the Inverted Repeat Lacking Clade, see Wojciechowski 2003 and references): genera involved have a star in the list above. Many Faboideae have a 50kb inversion in their chloroplast genome; Sophora, Myrospermum, Swartzia and their relatives lack this inversion (e.g. see Doyle et al. 1996). In taxa with this inversion the 2 gene has been lost several times, including in Desmodium and its relatives (it has moved to the nucleus), ORF84 has been lost many times, and accD (= ORF512, zpfA) has also been lost (Doyle et al. 1995).

For the phylogeny of dalbergioid legumes, see Lavin et al. (2000) and Ribeiro et al. (2007), for that of Amorpheae and their floral evolution (petals may be lost, or all look rather similar; a stemonozone may be developed; etc.), see McMahon and Hufford (2002, 2004, 2005) and McMahon (2005), for that of Robinia and its relatives, see Lavin et al. (2003), and for that of Psoraleae, see Egan and Crandall (2008).

For the aborting plumule in Lotus and Coronilla and their relatives, see Dormer (1945), for seed and embryo morphology, see Kirkbride et al. (2003), and for a supermatrix analysis of 2228 taxa, see McMahon & Sanderson (2006). Evolution seems not to have involved hybridization between genera (Käss & Wink 1997).

Synonymy: Aspalanthaceae Martynov, Astragalaceae Martynov, Ciceraceae W. Steele, Coronillaceae Martynov, Galedupaceae Martynov, Hedysaraceae Oken, Inocarpaceae Zollinger, Lathyraceae Burnett, Lotaceae Oken, Papilionaceae Giseke, Phaseolaceae Postel, Robiniaceae Vest, Sophoraceae J. Weinmann, Swartziaceae Bartling, Tamarindaceae Berchtold & J. Presl, Viciaceae Berchtold & J. Presl

• Fabaceae may be recognised by their compound, stipulate leaves whose leaflets are entire and often have wrinkled pulvini, and flowers with a single carpel, free petals (or two may be connate), and stamens either all similar in length, or if dissimilar, not regularly alternating longer and shorter. The fruit is usually dry and elongated, the often flattened seeds being borne in a single rank.

• "Caesalpinioideae" and Cercis and its relatives are woody plants that may be recognised by their usually once-compound leaves and monosymmetric flowers with the odd petal adaxial and inside the others in bud; the hypanthium is often well-developed.

• Mimosoideae are also mostly woody plants that have leaves that are often bicompound and with extrafloral nectaries. The flowers are rather small and are borne in groups, all flowers opening more or less simultaneously; the long, colored filaments form the visually attractive part of the inflorescence. Both the calyx and corolla are valvate, and both (and often the bases of the filaments) are connate. The seeds have a linea fissura.

• Faboideae are usually herbs or vines and often have once-compound leaves. The flowers are monosymmetric with the odd petal being adaxial and outside the others; the papilionoid flower consists of adaxial banner, paired wings and two connate petals forming the keel. The stamens have more or less connate filaments and the fruit is often explosively dehiscent, splitting down both sides and the valves twisting.

Fabaceae are a notably speciose clade, particularly the branches with Mimosoideae and Faboideae (Magallón & Sanderson 2001), and contain ca 9.4% of eudicots; it has been estimated that some 16% of all woody species in neotropical rainforest are members of this family (Burnham & Johnson 2004). Fabaceae began diversifying ca 60 million years ago ago (the stem group is little older), and the major clades had separated by ca 50 million years ago. Thus the clade [part of Caesalpinioideae + Mimosoideae] may date to 54 ± 3.4 million years before present, stem group Mimosoideae to ca 55 million years before present, crown group Mimosoideae to 44 ± 2.6 million years before present (Lavin et al. 2005). Wikström et al. (2001) date the clade to 79-74 million years before present (Quillaja not included in the analysis), with diversification some 68-56 million years before present; the Mimosoideae-Faboideae split is dated to 59-34 million years before present. Stem group Faboideae may date to 58.6 ± 0.2 million years before present, and the crown group may be about the same age (Lavin et al. 2005, the latter date is rather sensitive to the age of Fabaceae as a whole). Although there are a number of transoceanic disjunctions within Fabaceae, 51/59 of these are only 1-22 million years old (Schrire et al. 2005). Lavin et al. (2004) and Schrire et al. (2005) find it more profitable to think of diversification and distribution of Fabaceae in terms of vicariance of biomes rather than of the classic geographical areas; the North Atlantic land bridge may have been important in the Tertiary dispersal of legumes (Lavin et al. 2000). Within Faboideae, a number of divergences can be dated, including the separation of the speciose Astragalus from Oxytropis 16-12 million years ago, although diversification in both is relatively recent; radiation in the speciose aneuploid New World neoastragalus species started ca 4.4 million years ago (Wojciechowski 2004). Inga, with some 350 species and an important component of neotropical forests, seems to have diverged within the last two million years (Richardson et al. 2001b).

Lycaenidae-Riodininae-Riodinini, Lycaenidae-Curetinae and especially Lycaeninae-Lycaenini caterpillars are found on Fabaceae (Ehrlich & Raven 1964; Fiedler 1991, 1995), as are Pierid butterfly larvae (Coliadinae, Dismorphiinae: some 260 spoecies in 15+ genera, about a quarter of the records - see also Brassicales and Santalales, Braby & Trueman 2006). The diversity of caterpillars - especially that of "basal" butterfly groups - on Fabaceae is such that Janz and Nylin (1998) and Braby and Trueman (2006) suggested that Fabaceae might be the springboard for hostplant diversification of butterflies feeding on angiosperms in general (see also the introduction to Fabales). In another variant of insect-plant relationships, the flowers of Crotalaria are visted by Danainae and Ctenuchidae because the pyrrolizidine alkaloids they contain are used as the basis of the pheromones of these lepidoptera (also Asteraceae, and wilting plants of some Boraginaceae: Edgar et al. 1974; Pliske 1975; Boppreé 1986); Crotalaria is also involved with arctiid moths such as Utetheisa in that its secondary metabolites provide defence for the young, pheromones, etc., etc. (Eisner & Meinwald 1995). The jumping plant lice Psyllidae-Arytaininae are often associated with Fabaceae-Faboideae, especially genistoids, and especially in the Mediterranean-Macaronesian region, while Psyllidae-Acizzinae are associated with Mimosoideae in the Southern Hemisphere (Percy 2003; Percy et al. 2004). In Acacia s. str., well over 200 species of Phlaeothripidae (thrips) form galls and other habitations on species of subgenera Juliflorae and Plurinerves, although not on species of subgenus Acacia, which has only a single main vein, unlike the others (Morris et al. 2002). Bruchids (Chrysomeloidea-Bruchidae/Bruchinae), with some 1700 species and whose larvae eat seeds, have diversified considerably on Fabaceae; they were perhaps first associated with Faboideae, then moved on to other groups following the chemistry of the plants involved (esp. Kergoat et al. 2005a, b; see also Johnson 1989, 1990 [Acanthoscelides], Birch et al. 1989 [chemistry of the interaction], and Janzen 1969 [the complexity of the association between plant and weevil]). Two clades, made up largely of New World Acanthoscelides and predominantly Old World Bruchidius, dominate, and they may have radiated contemporaneously with their hosts, largely Fabaceae-Mimosoideae and Faboideae (elsewhere also on some Malvaceae, in particular); they can detoxify the non-protein amino acid, L-canavanine. The pattern of association of bruchid groups with mimosoids is interesting; individual bruchid genera tend to concentrate on members of a single mimosoid clade, often being found on adajcent clades in the tree (Kergoat et al. 2007). Finally, less widespread but very well known is the association of ants with some members of the old Acacia subgenus Acacia (= Vachellia). These includes the swollen-thorn acacias such as V. sphaerocephala which provide protein-rich Beltian bodies at the ends of the leaflets (the leaves have many leaflets, even for Acacia s.l.) as food for the ants and swollen stipular thorns for their homes (Janzen 1974b).

Indeed, the diversity of "secondary metabolites" in Fabaceae, perhaps especially in Faboideae, is remarkable; for instance, about 28% of all known flavonoids and about 95% of the isoflavonoid aglycone structures - over 1,000 alone - identified in plants are known from Fabaceae, and the isoflavonoids are restricted to Faboideae. Isoflavonoids may be phytoalexins (defence), and are perhaps also involved in nodulation (Hegnauer & Grayer-Barkmeijer 1993; Reynaud et al. 2004). In general Fabaceae have a very distinctive nitrogen metabolism. Non-protein amino acids are common (see e.g. Fowden et al. 1979, and nitrogen in the xylem sap is transported as a mixture of amino acids, amides, and sometimes also ureides; very little is transported as nitrate. Wojciechowski et al. (2003, 2004, see also Wojciechowski 2003) note than the evolution of some non-protein amino acids are taxonomically interesting, thus canavanine production seems to have originated in the ancestor of one major subgroup of Faboideae (it includes mirbelioids, millettioids, robinioids, and the large group lacking the inverted repeat in the chloroplast genome, and may date to 54.3 ± 0.6 million years before present - Lavin et al. 2005 - see tree above); canavine and alkaloid production are mutually exclusive. Flavonoids lacking the 5-hydroxy group are characteristic of Fabaceae (Seigler 2003), but I do not know at what level they are apomorphic. Pea albumin, a small sulphur-rich peptide with insecticidal properties, is known only from Faboideae where it may be a synapomorphy for the [hologalegina + millettioid] clade, being lost in some/all robinioids (Louis et al. 2007).

The distribution of nodulation within Fabaceae and variation in nodule morphology are of some systematic significance (see also J. J. Doyle 1994, 1998; J. J. Doyle et al. 1997). Although the nodulating bacteria are all members of the proteobacteria α-2 subclass, they do not form a monophyletic group; Agrobacterium (crown gall tumour) and others are also members of this group (Sprent 2001). The plesiomorphic infection morphology shows persistent infection threads and long-lived nodules (see also Parasponia - Cannabaceae), while more derived may be the absence of infection threads, the mitosis of infected cells, and a short life span for the nodules (de Faria & Sprent 1995; see also Corby 1988 & Sprent 2005 for nodule distribution). However, a number of Fabaceae, perhaps especially non-nodulated members, are ectomycorrhizal. Burkholderia, a ß-proteobacterium, is an effective nitrogen-fixing symbiont of some Faboideae and Mimosa, and other ß-proteobacteria can form nodules, albeit inffective, with Mimosoideae (Moulin et al. 2001; Elliott et al. 2007 and references); this kind of association may be quite common in the tropics (Sprent 2007). It appears that the acquisition of the ability to nodulate has occured more than once, perhaps even several times, with the family. Even within Faboideae, the nodulating Swartzia and immediate relatives may be sister to the rest of the subfamily (support is weak, see Ireland et al. 2000; Pennington et al. 2000; Lavin et al. 2005); other Faboideae also representing clades that are separate from the bulk of the subfamily do not nodulate, even if the bulk are nodulators (Sprent 2000, 2001, 2007). N-fixing in Fabaceae in particular usually involves gram-negative α-proteobacteria and nodule formation involves the production of Nod factors by the bacterium. Remarkably, in a few nodule-forming α-proteobacteria such as the photosynthetic Bradyrhizobium there is no nodABC gene (Giraud et al. 2007).

Rusts show an interesting pattern of distribution on Fabaceae. Uromyces is found predominantly on herbaceous Faboideae, but also on Bauhinia and one or two other woody taxa (being found, along with related genera, on Acacia in Australia alone), while Ravenelia is found on woody members of the family, i.e. "Caesalpinioideae", but also especially Mimosoideae (Savile 1976, 1979a, b; El-Gazzar 1979). In a number of species of Ravenelia the teliospores, thick-walled spores in which nuclear fusion and then meiosis occur, are aggregated into groups, and these telial heads may mimic the groups of pollen grains (polyads) that are common in Mimosoideae. Stingless Trigona bees may pick up the telial heads and polyads as they forage for pollen. However, Ravenelia is only very rarely found on Australian Acacia; the distributions of rusts, acacias and trigonid bees all break at about Wallace's Line.

Although most Fabaceae have compound leaves and leaflets with entire margins, there is extensive variation on this theme. In Acacia s. str. (the old subgenus Phyllodinae), the leaves of the mature plant are much modified and are often called phyllodes, but seedlings and regeneration shoots may have once or twice compound leaves. Kaplan (1980) suggested that these "phyllodes" were not equivalent to the petiole of a compound leaf, but to the leaf as a whole. In early development, instead of there being two, adaxial meristems that went on to develop the leaflets/pinnae, there was a single, broader adaxial meristem that developed to produce the entire leaf; these phyllodinous leaves are flattened at right angles to the plane of flattening of a normal leaf. In compound leaves, the leaflets/pinnae became lateral in position by secondary reorientation. In some species of Acacia phyllodinous leaves are densely set along the stem, but only some are associated with stipules and buds, others lacking both. A number of Faboideae (e.g. Vicia, Pisum) are tendrillar vines, the tendrils being modified terminal leaflets; in Lathyrus aphaca the photosynthetic function of the leaf is taken over by the large stipules, the rest of the leaf being tendrillar, while L. nissolia lacks tendrils and has a phyllodinous leaf. The leaves may be reduced to a single more or less connate pair of leaflets, as in Bauhinia, named after the botanical brothers Caspar and Jean Bauhin. Some species of Mimosa and other genera have leaves that are sensitive to touch, stimulus transmission occuring as membrane depolarisation is propagated down the petiole and along the stem; folding of the leaf is caused by tugor changes in the cells of the pulvini at the bases of the leaf and leaflets (for the anatomy of the pulvinus, which has an endodermis, see Rodrigues & Machado 2007). In taxa like Albizzia (Samanea) saman, similar movements occur as the leaflets fold towards the evening when the light is failing, or just when there is heavy cloud cover, this behaviour being responsible (in some tellings of the tale) for its name, the rain tree, while in Desmodium gyrans the single pair of lateral leaflets move intermittently without bein touched, the speed of movement increasing with the temperature.

There is much floral diversity within the family. The "normal" (for flowering plants) floral orientation of Mimosoideae may be secondary; it is also to be found in caesalpinioids like Ceratonia, but not in either Cercis or Bauhinia (see Tucker 1989; Herendeen et al. 2003; Luckow et al. 2005). In general, the monosymmetric flowers of Fabaceae encompass a variety of morphologies; as Bruneau et al. (2005, p. 201) note of caesalpinioid legumes, "zygomorphy is expressed as a multitude of homoplasious morphs". Polysymmetry in Cadia, a "reversal", is the result of dorsalization of the flower (the same basic principle as peloria in Antirrhinum: Citerne et al. 2006); Cadia is sister to the largely Cape group of genera of the Podalyrieae-genistoids (Boatwright et al. 2008). Details of hypanthium evolution within Fabaceae are unclear; it seems to have become much reduced and lost several times. The "pea flower" morphology is best developed in many Faboideae and is characterised by the more or less erect banner petal which sometimes has colour patterning, the wing petals, and the interlocking keel petals enclosing the stamens. Such flowers may attract a diversity of pollinators that visit the flowers for various rewards. If the androecium is monadelphous, the pollinator reward is often pollen, and this can be delivered by a pump secondary pollen presentation mechanism, while if it is diadelphous, the reward is often nectar, the nectary lying between filament tube and gynoecium. Taxa like Cytisus have explosive pollination. Erythrina is pollinated by both perching and hovering (humming) birds, and both floral morphology and how the flowers and inflorescences are held varies according the requirements of these different visitors (Bruneau 1997). In Hardenbergia violacea the colour patterning on the standard may mimic an anther (Lunau 2006). Many Mimosoideae have polyads which are caught in the cup-shaped stigma which is of the appropriate size for the polyad of that species, and there are about as many ovules as there are pollen grains in the polyad (Kenrick 2003 for references, and what this pollination mechanism does to the breeding system). In Calliandra s. str. the polyads have an associated viscin body by which the they are attached to the pollinator, here, however, the stigma is muach larger and capitate (Greissl 2006).

The legume s. str. is a single carpellate fruit that dehisces explosively along both sutures, the two valves twisting as they separate. It is common in European-North American Faboideae, but it occurs also in the other subfamilies, including in Bauhinia, the clade sister to the rest of the family (Cercis is not explosively dehiscent, but is otherwise similar). However, there is a great diversity of fruit morphology in the family: Variously winged fruits, fleshy fruits, fruits breaking up into single-seeded units in differnt ways, fruits modified for animal transport with spines and hooks (e.g. the velcro-type hooks on Desmodium). Arillate seeds are common, and seeds that have red and black color patterns that mimick arils (e.g. Abrus, Erythrina) are well known, as are seeds with fleshy coats; in many taxa the seed coat is very hard and may need scarification if germination is to occur (for fruits and seeds, see Corner 1951; van der Pijl 1956; Kirkbride et al. 2003; etc.).

Fabaceae are monophyletic based on both molecular and morphological analyses, whether or not the family is dismembered into three or not (Caeslpiniaceae are paraphyletic, Mimosoaceae largely monophyletic, Fabaceae s. str. monophyletic - see Chappill 1994 for an interesting morphological analysis). Characters of "Caesalpiniodeae" woods include rays usually more than 20 cells tall, silica bodies present, and axial canals (Evans et al. 2006); how these fit onto the tree is currently unclear. Cercis and Bauhinia may be sister to all other Fabaceae (e.g. J. J. Doyle et al. 2000 and references; Bruneau et al. 2001), although they are placed sister to Detarieae s.l. (inc. Cynometra) sometimes with only with moderate support (Wojciechowski et al. 2004; Lavin et al. 2005; Forest et al. 2007b), the combined clade being sister to the rest of Fabaceae. Detarieae include genera like Cynometra Tamarindus and Amherstia and have also been placed by themselves as sister to all Fabaceae minus Cercideae; Duparquetia is also in this general area (Forest et al. 2002; Tucker et al. 2002). Detarieae are florally very variable: flowers poly- to disymmetric, C 0-5, A 3(+ staminodes)-10, etc. Vestured pits, which they and Cercideae lack, are also absent in Cassieae. Mimosoideae are very largely monophyletic, Faboideae are monophyletic, but their recognition makes Caesalpinioideae paraphyletic. In addition to placing Cerceae, etc., as sister to the rest of Fabaceae, Wojciechowski et al. (2004) found Dialeae were sister to the rest. There were then two main clades, the Mimosoideae, to which Ceratonia, Gleditsia, etc., Caesalpinieae, Cassieae, and Cercideae (all "Caesalpinioideae") are more or less successively sister taxa, and Faboideae.

Faboideae are monophyletic, but the recognition of this subfamily (and Mimosoideae) makes Caesalpinioideae paraphyletic. Within Faboideae, Swartzieae, woody, nodulators, lacking bracteoles, with very variable flowers and arillate seeds, may be sister to the rest, but support is weak and the exact circumscription of Swartzieae is unclear (Ireland et al. 2000; Pennington et al. 2000; Lavin et al. 2005); it may well be largely restricted to Swartzia. Some other Faboideae clades (they include some ex-Swartzieae) separating early from the bulk of the subfamily also do not nodulate (Sprent 2000, 2001). Many Faboideae have a 50kb inversion in their chloroplast genome; Sophora, Myrospermum, Swartzia and their relatives lack this inversion (e.g. see Doyle et al. 1996). There has also been the loss of the 25kb chloroplast inverted repeat; this characterises a largely temperate, epulvinate, herbaceous and very speciose group, although Wisteria is also a member of this clade (the IRLC - the Inverted Repeat Lacking Clade, see Wojciechowski 2003 and references): genera involved have a star in the list above. A topology (simplified) for Faboideae in general including [swartzioids: SWAR [Cladrastis, etc., [genistoids: GEN, [Amorpheae + dalbergioids = dalbergioids s.l.: DAL], [baphioids: BAPH [mirbelioids: MIRB [[Indigofereae + milletioids: MILL] [robinioids: ROB + Inverted Repeat Loss Clade: IRLC]]]]]]] seems moderately well supported (see also McMahon & Sanderson 2006). The [robinioids + Inverted Repeat Loss Clade] clade are called the hologalegina clade. For the phylogeny of dalbergioid legumes, see Lavin et al. (2000), for that of Amorpheae and their floral evolution (petals may be lost, or all look rather similar; a stemonozone, a tube formed by the adnation of filaments to the corolla, may be developed; etc.), see McMahon and Hufford (2002, 2004, 2005) and McMahon (2005), for that of Robinia and its relatives, see Lavin et al. (2003), and for a supermatrix analysis of 2228 taxa, see McMahon & Sanderson (2006). The IRLC clade is characterized not only by the loss of the inverted repeat, but the compound leaves lack pulvini and the KNOX1 gene is not expressed early in development, although the (normally floral) FLO/LFY gene is (Champagne et al. 2007). Astragalus is an extremely speciose genus characterising drier areas of both hemispheres, and a number of taxa have leaf rhachis spines. Extensive phylogenetic studies (e.g. Wojciechowski 1993, 2004; Kasempour Osaloo et al. 2004; Scherson et al. 2004) show most New World taxa are aneuploid (n = 11-15) and form a monophyletic group, other species are base 8. Oxytropis is sister to Astragalus. In Trifolium the calyx and corolla involved in fruit dispersal mechanisms, and again the American species form a monophyletic group (Ellison et al. 2006; Liston et al. 2006).

Root nodule morphology may help delimit groups of genera in Faboideae (Wojciechowski 2003). For other information on phylogeny, see Hu et al. (2000), Kajita et al. (2001) and Lavin et al. (2005). Taxa like Swartzieae, Sophora, and a few others, lack a 50kb inversion in the trnL intron in the large single-copy region that is found in other members of the subfamily (J. J. Doyle et al. 1996, 1997; Pennington et al. 2001; Wojciechowski et al. 2004).

Prenner (2004c) suggests that a slight asymmetry in the early development of the androecium (the adaxial median stamen is initiated slightly off the median axis) occurs in more "basal" Faboideae and also some "Caesalpinioideae". Caesalpinioideae have 4(-7)-nucleate tapetal cells, while those of Mimosoideae and Faboideae are 1-nucleate (Wunderlich 1954) - this character may have some systematic significance. The style is at least sometimes hollow, although the cavity arises in various ways, including by lysigeny (Lersten 2004). The carpels may have five traces and are quite often open during development in "Caesalpinioideae", but not, apparently, in Cercideae, Mimosoideae or Faboideae (Tucker & Kantz 2001). The embryo sac of some Faboideae (?elsewhere) more or less protrudes into the micropyle, as in Archevaletaia (Maheshwari 1950). There is a great deal of variation in the development of the embryo suspensor, even within Faboideae (Lersten 1983). The ratio of galactose to mannose in the galactomannans (storage polysaccharides) in seeds of Fabaceae may be of phylogenetic interest (Buckeridge et al. 2000).

For domestication of the peanut, see Dillehay et al. (2007).

Fabaceae s.l. are often referred to their own order, as in both Cronquist (1981) and Takhtajan (1997). They can be confused with Connaraceae (Oxalidales), although the latter lack stipules, their flowers are polysymmetrical and have stamens of two distinctly different lengths, and their gynoecium is frequently multicarpellate. However, in both the RP122 chloroplast gene has moved to the nucleus! Also, the ovaries of both have adaxial furrows (cf. the ventral slit: Matthews & Endress 2002). Fabaceae have also been linked with Sapindaceae (e.g. Dickison 1981b), here in the rosid II group and also with compound leaves, but there is little support - and none molecular - for such an association.

For general information see Polhill and Raven (1981), Crisp and Doyle (1995), Doyle and Luckow (2003), and Lewis et al. (2005: well-illustrated summary of geographic distribution, etc., of all the genera; some of the taxa recognised in the body of the book are para/polyphyletic). For general chemistry, about which a great deal is known, see Hegnauer (1994, 1996), Southon (1994), and Hegnauer and Hegnauer (2001); for additional details, see also Frohne and Jensen (1992) and Waterman (1994: secondary metabolites), for the evolution of these secondary metabolites, see Wink and Waterman (1999), Wink and Mohamed (2003: particularly useful) and Wink (2003), and for polysaccharides and flavonoids in particular, see Hegnauer and Grayer-Barkmeijer (1993) and Harborne and Baxter (1999), for terpenoids, see Langenheim (1981, 2003). See also Ferguson and Tucker (1994) for general information, and for wood anatomy, see Baretta-Kuipers (1981), starch, Czaja (1978), embryology, etc., Dnyansagar (1970), embryo suspensors, Lersten (1983) and Tucker (1987), general floral and inflorescence morphology, Endress (1994b), epidermal wax crystals, Ditsch et al. (1995), gene and intron loss, J. J. Doyle et al. (1995), floral development, Tucker (1996 and references, 2003), cotyledon areoles, Endo and Ohashi (1998), for phylogeny, see Wojciechowski et al. (2004: matK), and for diversification in Cape genistoids, see Edwards and Hawkins (2007).

Quillajaceae + Polygalaceae: ?

SURIANACEAE Arnott, nom. cons.   Back to Fabales

Woody; ellagic acid?; cork also in inner cortex; storying +/0; wood fluorescing?; nodes 3:3 (1:1 - Suriana); sclereids +; petiole bundle arcuate to annular; leaves spiral or 2-ranked (pinnate, leaflets alternate, articulated), (stipules 0 - Suriana); inflorescence cymose, usu. terminal, pedicels articulated; K connate basally or not, quincuncial, C (0), contorted, shortly clawed or not, staminodial tissue ± foriming a ring round the C base, A (= and opposite K) 10, obdiplostemonous, (gynophore and disc - Recchia), G 1-5, when 5 opposite C, 1-5 unitegmic campylotropous ovules/carpel, ovules surrounded by mucilage, hypostase +, styles ± gynobasic, stigma clavate to capitate; fruit a berry, drupe or nut, endocarp with outer layer of palisade sclereids, other cells apart from the inner epidermis isodiametric, K persistent, accrescent or not; exotestal cells enlarged, cuboidal, tanniniferous, rest crushed [ca 7 cells thick]; chalazal endosperm haustorium +, embryo curved or folded, cotyledons incumbent; n = ?; germination epigeal, phanerocotylar.

5[list]/8 Mostly Australian, also Mexico (Recchia), pantropical (Suriana maritima) (Map: from van Steenis & van Balgooy 1966 [blue - Suriana maritima]). [Photo - Flower]

For relationships, see Forest et al. (2007b); [[Recchia + Lundellia] [Suriana [Cadellia + Stylobasium]] seems to be the cladistic structure in the family. The vegetatively "atypical" Suriana is the only genus whose embryology has been studied and the whole family is little known chemically.

The family is vegetatively very heterogeneous, although quite homogeneous in wood anatomy (Webber 1936). The exotesta of Suriana is described as being green (Rao 1970).

Surianaceae were included in Rosales by Cronquist (1981) and in Rutales by Takhtajan (1997), and the family used to be included in Simaroubaceae (here in Sapindales). Although the sieve tube plastids of Stylobasium are distinctive, with both protein and one or a few starch grains (Behnke et al. 1996), there seems little reason to recognise Stylobasiaceae as a monotypic family; Suriana has more ordinary plastids with starch grains alone.

For more information, see Jadin (1901) and Boas (1913: both vegetative anatomy), Gutzwiller (1961: general), Rao (1970: embryology, etc., under Simaroubaceae), Hegnauer (1973, as Simaroubaceae: chemistry), Gadek and Quinn (1992: pericarp), Ito and Tobe (1994: embryology), Crayn et al. (1995: relationships), Schneider (2006: general), and floral development (Bello et al. 2007: Suriana only). Cadellia - Benson s.n. = NSW 408528 (anatomy); Stylobasium - Latz 12864 (fruit), Strid 20708 (anatomy).

Synonymy: Stylobasiaceae J. Agardh (sieve tube plastids with starch grains and protein filaments forming a peripheral shell).

POLYGALACEAE Hoffmannsegg & Link, nom. cons.   Back to Fabales

Trees, lianes or (echlorophyllous) herbs; (successive cambia +); saponin +; nodes 1:1; styloids 0; (stomata other than anomocytic); plant glabrous or with unicellular hairs; branching from previous flush; often paired glands [crateriform extrafloral nectaries] or thorns at nodes (elsewhere); inflorescence indeterminate; flowers monosymmetric, K quincuncial, caducous, C 5, A (2-)8(-10), median adaxial A often absent, pollen polycolporate, surface psilate or foveolate, (disc excentric), G connate, micropyle zigzag (exostome often long; exostomal), nucellar cap +, style long, stigma dry; fruit a berry; seed often hairy, (exostomal/funicular aril +), exotesta subsclerotic, endotestal cells ± palisade or not, U-thickened, crystalliferous (not); hypostase enlarges; endosperm copious or not, starchy.

Ca 21[list]/940 - four tribes below. World-wide, except the Arctic and New Zealand. [Photo - Flower]

1. Xanthophylleae Chodat

Plants Al accumulators; wood parenchyma apotracheal, diffuse; glands at nodes, (conspicuous domatia on leaves), K quincuncial, unequal, A (7-)8(-10), G [2], placentation parietal, 2 or more apotropous ovules/carpel, in two rows, outer integument 4-12 cells across, stigma small, bilobed (capitate); (fruit irregularly dehiscent); testa multiplicative; hypostase massive; n = ?

1/95. Indo-Malesia (Map: from van der Meijden 1982).

Although the seed coat anatomy is often undistinguished, some species have Polygala-type testa anatomy (see family characterisation); irregularly loculicidally dehiscent fruits also occur.

For a monograph, see van der Meijden (1982).

Synonymy: Xanthophyllaceae (Baillon) Reveal & Hoogland

The Rest: A ± adnate to petals, variously connate, often monadelphous, anthers opening by short apical slits, 1 epitropous ovule/carpel.

2. Polygaleae Chodat

Also herbaceous; at least some smell of wintergreen, tannins 0 [Polygala]; pits vestured; banded paratracheal parenchyma +; (glands at nodes); two adaxial lateral K = wings, 2 abaxial lateral K, minute, two connate adaxial C = the standard, abaxial C = the keel, often fringed, 2 abaxial-lateral C minute, (A 2-)8, G [2] (adaxial member suppressed), stylar canal +, stigma bilobed, ± asymmetrical; fruit an often flattened capsule, drupe or samara, (K persistent, green - Polygala, etc.); caruncle + (chalazal aril +; no appendages)n = 6+.

Ca 13/830: Polygala (325, generic limits unclear), Monnina (180), Muraltia (120: mostly the Cape, diversification relatively recent, many within 10 my - Forest et al. 2007a), Securidaca (80). World-wide, except The Arctic and New Zealand.

Epirixanthes is an echlorophyllous mycoheterotroph. Although genera like Xanthophyllum may have paired glands at the nodes, other genera seem to lack anything faintly comaparable with stipules, and where stipules might be lost in this part of the tree is uncertain.

In Polygala myrtifolia, with eight stamens, it is apparently the two stamens in the median plane - i.e., on opposite sides of the flower - that are lost (Prenner 2004d).

For floral morphology and development, see Krüger and Robbertse (1988) and Krüger et al. (1988).

3. Carpolobieae Eriksen

(Glands at nodes); abaxial C keeled, A (4) 5, G [3], stigma capitate; n = 9-11.

2/6. Tropical Africa.

4. Moutabeae Chodat

Plants Al accumulators; banded apotracheal parenchyma +; glands on leaves (and at nodes); abaxial C not keeled, A (6-)8-10, G [3-8], stigma capitate; funicular aril +; n = 14.

4/15. Tropical America, New Guinea to New Caledonia. [Photos - Flowers, Flower - Close-up, Petioles, Branch, Petioles with ants, Flower with moth]

For vegetative anatomy, see Styer (1977).

Synonymy: Diclidantheraceae J. Agardh, Moutabeaceae Endlicher

• Polygalaceae are woody or herbaceous plants that may be recognised by their often yellowish-drying simple and entire leaves; there are quite frequently paired glands at the nodes or glands or domatia on the leaf blades. The flowers are usually monosymmetric, and are more or less papilionaceous. They range from having five rather large sepals and five petals - not strongly papilionaceous - to having two of the sepals much enlarged and coloured (the "wings" of the flower), two of the petals much reduced, and the three remaining petals modified as "standard" and "keel" - strongly papilionaceous. There are two or more carpels and a single style.

Wikström et al. (2001) date the origin of the clade to 68-66 million years before present. In a study of ant dispersal in Polygalaceae, which is quite common in Polygaleae, it seems that caruncles may be an apomorphy of Polygaleae, although chalazal arils have also evolved more than once in this clade, and they and caruncles have been lost, too (Forest et al. 2007b). Evolution of these elaiosomes is suggested to have occured (69.9-)54-50.5(-35.2) million years before present, well after initial diversification of the ant clades attracted to them.

Of the four groups mentioned above, Moutabeae may be paraphyletic (Persson 2001: trnL-F), although adding rbcL data suggests they are monophyletic (Forest, in Eriksen & Persson 2006), and morphology points in this direction (Eriksen 1993b); the other three groups appear to be monophyletic (although Carpolobieae are only weakly supported). However, all four tribes are strongly supported in a three-gene analysis (Forest et al. 2007b), and Xanthophylleae are sister to the other three tribes; relationships between the latter are unclear. Polygala and Bredemeyera are grossly paraphyletic (Persson 2001). For Emblingiaceae, often included in (e.g. Mabberley 1997) or near (e.g. Takhtajan 1997) Polygalaceae, see Brassicales.

The flower in Polygalaceae is quite differently constructed from that of Fabaceae, although quite often both looking and being functionally very similar (but see Prenner 2004d). However, the flowers of Polygala, particularly similar in overall appearance to those of some Fabaceae, are unlikely to represent the plesiomorphic condition of the family, and overall floral variation in Polygalaceae is very considerable. In at least some North American species of Polygala pollen is presented on the sterile lobes of the asymmetrical stigma (secondary pollen presentation: Weekley & Brothers 1996). The tricolpate pollen of Balgooya is probably derived; some Polygalaceae such as Heterosamara have asymmetric, almost boat-shaped pollen grains (Banks et al. 2008).

Some general information is taken from Eriksen (1993a, b: see the latter for a morphological phylogeny) and especially from Eriksen and Persson (2006), that on ovule and seed from Verkeke (1985, inc. integument thickness, the inner integument of Securidaca is up to 9 cells across, 1991), Takhtajan (2000: ovule and seed), and Banks et al. (2008: pollen morphology and evolution). For chemistry, see Hegnauer (1969, 1990). Also see Polygalaceae website (Freire-Fierro 2001 onwards).