LIGNOPHYTA

True roots +; lateral meristems: cork cambium producing cork abaxially, vascular cambium producing phloem abaxially and xylem adaxially.

EXTANT SEED PLANTS/SPERMATOPHYTA

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 derived from (some) sinapyl and particularly coniferyl alcohols, thus containing p-hydroxyphenyl and guaiacyl lignin units, (lignins derived from p-coumaryl alcohol, i.e. S [syringyl] lignin units); true roots present, apex multicellular, xylem exarch, and 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 and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, plastids with starch grains; phloem fibres +; stem cork cambium superficial, root cork cambium deep seated; leaves with single trace from sympodium ["nodes 1:1"]; stomata ?; leaf vascular bundles collateral; leaves megaphyllous [determinancy evolved first, then ad/abaxial symmetry], spiral, simple, lamina with vein density up to 5 mm/mm2 [mean for all non-angiosperms 1.8]; axillary buds associated with at most some leaves; prophylls [including bracteoles] two, lateral; 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, developing after pollination, 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 duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.

MAGNOLIOPHYTA

Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, non-hydrolysable tannins, quercetin and/or kaempferol +, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common, positive Maüle reaction [syringyl:guaiacyl ratio more 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; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, with gelatinous fibres; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, cytoplasm not occluding pores of sieve plate, companion cells from same mother cell that gave rise to the sieve tube; sugar transport in phloem passive; nodes unilacunar [1:?]; stomata with ends of guard cells level with pore, paracytic, outer stomatal ledges producing vestibule; leaves petiolate, lamina [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; most/all leaves with axillary buds; flowers perfect, pedicellate, polysymmetric, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P not sharply differentiated, with a single trace, outer members not enclosing the rest of the bud, often smaller than inner members; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], ± embedded in the filament, 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, 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, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, dry [not secretory]; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, megaspore tetrad linear, functional megaspore chalazal, lacking sporopollenin and cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; P deciduous in fruit; seed exotestal; pollen binucleate at dispersal, trinucleate eventually, germinating in less than 3 hours, pollination siphonogamous, tube elongated, growing at 80-600 µm/hour, with pectic outer wall, callose inner wall and callose plugs, growing between cells, penetration of ovules via micropyle [porogamous] within ca 18 hours, distance to first ovule 1.1.-2.1 mm, tube moves between nucellar cells; double fertilisation +, endosperm diploid, cellular [micropylar and chalazal domains develop diffently, first division oblique, micropylar end initially with a single large cell, divisions uniseriate, chalazal cell smaller, divisions in several planes], copious, oily and/or proteinaceous, embryo cellular ab initio, minute; germination hypogeal, seedlings/young plants sympodial; Arabidopsis-type telomeres [(TTTAGGG)n]; whole genome duplication, ndhB gene 21 codons enlarged at the 5' end, 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 three copies of the PHY gene, [PHYB [PHYA + PHYC]].

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. This is because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable homoplasy as well as variation within and between families of the ANITA grade 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. 2009b for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous... Ther are other features such as a nucellus only one (Nymphaeales) to three cells thick above the embryo sac and a stylar canal lacking an epidermal layer that appear to be plesiomorphous for basal grade angiosperms (Williams 2009), however, where on the tree a thicker nucellus and a stylar epidermal layer are acquired has not been indicated.

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

Evolution. Divergence & Distribution. A fossil-based estimate of the age of this clade is ca 113 million years (Crepet et al. 2004), while Soltis et al. (2008: a variety of estimates) give the age of this clade as 180-132 million years and Magallón and Castillo (2009) offer still other ages - ca 229 million years for relaxed and 127 million years for constrained penalized likelihood datings, while Moore et al. (2010: 95% highest posterior density) suggest an age of (162-)155(-145) million years and Davies et al. (2011: 95% credibility intervals) suggested ages of (231-)197(-169) million years, towards the upper end of the various suggestions. Bell et al. (2010) suggest ages of or million years depending on the method used; note that this is the divergence of Nymphaeaales from Amborella.

Presence of vessels is optimised here, however, given their distinctive morphology in at least some Nypmphaeales (Carlquist & Schneider 2009; Schneider & Carlquist 2009), they may have arisen twice in this part of the tree. Feild (2005) suggests that vessels may have evolved in plants growing in humid conditions, and Gnetales and fossil groups with vessels may also have been growing in such conditions; on the other hand, and it would seem unlikely for vessels to have evolved in aquatics, and members of all three families have vessels in at least some parts of the plant. Sperry et al. (2007) discuss features of what they call "basal vessels"; these include little difference between pitting of the end and lateral walls, incomplete break-down of the pit membranes, etc. Bannan (1934) and Mauseth (2009) describe the major features of angiosperm and gymnosperm wood; despite lacking vessels, as in most gymnosperms, the wood of Amborella does have a small amount of parenchyma (Carlquist & Schneider 2001); it of course lacks bordered pits with margo-torus construction.

For discussion as to where characters of pollen morphology and development are to be placed on the tree, see Taylor and Osborn (2006) and also Friis et al. (2009b); it partly depends on how the characters are defined and partly on the recent discovery of fossil Nymphaeales that do not have the pollen characteristics of extant members of the clade.

Chemistry, Morphology, etc. For cell lineages in the embryo sac see Huang and Russel (1992) and Friedman (2006); identification of the pattern above apparently goes back to Porsch (1907), although it has been observed for relatively few plants. For embryo sac evolution, see Friedman and Ryerson (2009). For the possibility of a genome duplication at about this position, see Cui et al. (2006) and dePamphilis et al. (2009).

NYMPHAEALES Dumortier  Main Tree, Synapomorphies.

Aquatic herbs, plant rhizomatous; cambium 0; 4-celled uniseriate secretory trichomes with a large terminal cell [hydropoten]; starch grains compound; primary root soon aborts; root apex with secondary dermatogen, etc., epidermis derived from outer layer of cortex [unknown from Hydatellaceae]; trichoblasts in vertical files, proximal cell smaller; diaphragms in root aerenchyma; mycorrhizae 0; primary stem with ± scattered vascular bundles; protoxylem lacunae +; secondary thickening 0; nodes?; aerenchyma common; stomata anomocytic; leaf base broad; bracts 0; pollen boat-shaped, tectum continuous; ovule with semi-annular [hood-shaped] outer integument; first division of endosperm transverse, chalazal cell undivided, ± enlarged and elongated, haustorial; P persistent; seeds exotestal, exotesta ± palisade, operculum +, operculum endotegmic [?all], hilum outside operculum; endosperm scanty, perisperm +, copious, starchy, precocious, cells ± multinucleate, embryo broad, suspensor 0; germination hypogeal; intergenic inversion in chloroplast inverted repeat. - 3 families, 6 genera, 74 species.

Evolution. Divergence & Distribution. Wikström et al. (2001) suggested a stem age for the clade of some 171-153 million years before present. Magallón and Castillo (2009) suggested a crown group age ca 112 million years ago, and although fossil-based estimates are ca 90 million years (Crepet et al. 2004), but substantially earlier dates are likely (Friis et al. 2009b). Cretaceous fossils assignable to Nymphaeaceae are quite common, and it has been suggested that Nymphaeales were "the first globally diverse clade" (Borsch " Soltis 2008: p. 1051).

The curious fossil Archaefructus, probably an aquatic plant and about 124 million years old, has been linked with Hydatellaceae (Doyle & Endress 2010; Doyle 2008b), although they have little in common in terms of overall appearance. Morphological analyses place the Early Cretaceous Monetanthus in an embedded position within Nymphaeaceae (Friis et al. 2009b), in which case its distinctive reticulate-perforate pollen is independently derived both within Nymphaeales and at the node above Nymphaeales along the spine of the angiosperm tree.

Saarela et al. (2007) suggest a few additional possible synapomorphies for Nymphaeales, and Borsch et al. (2007) discuss the evolution of a number of floral characters.

Chemistry, Morphology, etc. Hydrolysable tannins in this group (e.g. in Nuphar) are different to those found elsewhere (Gottlieb et al. 1993; Ishimatsu et al. 1989) - although of course Hydatellaceae are here, as in many other features, very poorly known. Although there are minute perforations in the end walls of the cells that make up the water conducting tissues in some Nymphaeaceae, they hardly have the morphology of what are called vessel elements elsewhere, however, there are vessels of a variety of types in the roots in the stems of Brasenia. Hydatellaceae also have vessel elements with scalariform perforation plates, although these are absent from the leaves. The distinctive uniseriate trichomes found in all groups may secrete nectar or mucilage, or they may be involved in ion exchange (Vogel 1998a); Wilkinson (2006) calls the trichomes on the leaves, hydropotes. It is possible that there are epidermal oil cells in Nymphaeaceae (Wilkinson 2006); do they contain ethereal oils? For discussion as to whether or not Nuphar has bracts, see Schneider et al. (2003). The inner bracts found in some Hydatellaceae and the inner petals of Cabomba are notably slow in developing (Rudall et al. 2007). If the corolla represents sterilised stamens, as is believed, possession of external staminodes will probably be another synapomorphy at least for [Nymphaeaceae + Cabombaceae]. Some genera in all families have exotestal cells that are neither very tall nor much thickened (Hamann et al. 1979; Collinson 1980). For the distinctive single-celled chalazal haustorium, see Rudall et al. (2009b).

Phylogeny. Recent studies (Saarela et al. 2006, esp. 2007, several genes from two compartments, morphology: Friis & Crane 2007 [commentary]) place Hydatellaceae firmly with Nymphaeales, and sister to [Cabombaceae + Nymphaeaceae]; the sequence that placed Hydatellaceae in Poales was a chimaeric pcr recombinant involving a grass and a moss. Many of the morphological features of Hydatellaceae that made it so different from other monocots are consistent with this new position - Hamann (1998) even noted that the antipodal cells were absent or degenerated early, and absence of these cells would almost be expected if Hydatellaceae were placed here, indeed, recent work (Friedman 2008a; Rudall et al. 2008) shows it has the distinctive 4-celled embryo sac of other Nymphaeales and Austrobaileyales.

Previous Relationships. Hydatellaceae are superficially like Centrolepidaceae, both being very reduced morphologically, and indeed Hydatellaceae have been misidentified as that family. It is unclear if the gynoecium is 1- or 3-carpellate; the fruits of Trithuria open by three valves, so they look rather monocot-like. Although Hydatellaceae have long been considered to be monocots, largely because of this superficial similarity to Centrolepidaceae, the combination of characters they show has been recognised as being unique in that group, indeed, it makes them very distinctive within monocots as a whole (e.g. Hamann et al. 1979; Dahlgren et al. 1985). Hydatellaceae are sister to Xyridaceae in Stevenson et al. (2000; see also Stevenson & Loconte 1995); both have latrorse anthers and an operculum "stopper" that is tegmic in origin. Trithuria and Xyris appear as sister taxa (weak support) and in turn sister to Mayaca (still weaker support), although other Xyridaceae are not immediately related (Michelangeli et al. 2003). However, although Bremer (2002) noted that Mayacaceae and Hydatellaceae might be weakly associated with Xyridaceae or Eriocaulaceae, depending on what taxa were included in the analysis, there were a number of long branches in this area and he excluded the first two families from his final analysis, while Janssen and Bremer (2004) suggested that the association of Hydatellaceae with Mayacaceae was probably an artefact (see also Chase et al. 2006). This last suggestion was correct (see above).

Includes Cabombaceae, Hydatellaceae, Nymphaeaceae.

Synonymy: Barclayales Doweld, Cabombales Richard, Euryalales H. L. Li, Hydatellales Reveal & Doweld, Hydropeltidales Spenner - Hydatellanae Reveal, Nymphaeanae Reveal - Nymphaeidae Takhtajan - Hydropeltopsida Bartling, Nymphaeopsida Horaninow

HYDATELLACEAE U. Hamann, nom. cons.   Back to Nymphaeales

(Plant annual), growth sympodial, rhizome short, erect; chemistry?; vessels 0; leaves linear, with a single vein; plant monoecious; inflorescence axillary, scapose (sessile), capitate, with involucral bracts; P 0; staminate flowers: A 1, filaments long, slender; endothecium 0; tapetal cells?; pollen with spinules; carpellate flowers: G 1, three vascular bundles equidistant, stigma penicillate, of rows of plump cells; ovule 1/carpel, pendulous, anatropous, apotropous, micropyle bistomal, parietal cells 0, nucellar cap +; (two embryo sacs developing); fruit a follicle or an achene; apart from exotesta, other layers ± collapsed, tanniniferous; embryo undifferentiated; n = ?; seedling - see below.

Hydatellaceae

1[list]/10. India, New Zealand and Australia (map: from Cooke 1987; FloraBase 2004).

Evolution. Divergence & Distribution. The curious fossil Archaefructus, ca 124 million years old, is placed sister to Hydatellaceae in recent morphological analyses (Doyle & Endress 2007, 2010; Doyle 2008b). Although they have little in common in terms of overall appearance, Archaefructus, too, may be another aquatic angiosperm with very unconventional floral morphology. Rather younger pollen fossils, Monosulcites riparius, from Eastern Siberia of ca 75-70 million years age have been identified as Trithuria, but the family may be in the pollen record from the Isle of Wight in rocks of some 130 million years of age... (Hoffmann & Zetter 2010).

Floral Biology & Seed Dispersal. For reproductive ecology - wind pollination, self pollination - see Taylor et al. (2010); the pollen tubes grow down the multicellular hairs under the cuticle (Prychid et al. 2011).

Chemistry, Morphology, etc. The sieve tube plastids were reported as having triangular proteinaceous inclusions, but these inclusions appear to be of the starchy type as are more to be expected in this part of the tree (Tratt et al. 2009). The inflorescence is described as being cymose and capitate, although bractless and with highly reduced flowers, i.e., it is a sort of pseudanthium, although alternative interpretations are possible (Rudall et al. 2007a, 2009a). Early work suggested that the carpels might be initiated outside the stamens, and this has been confirmed (Rudall et al. 2007a); staminate flowers are the first to be initiated in the cymose inflorescence (see also Begoniaceae). Hairs with possible apical secretory cells are known only from the inflorescences. The pedicels seem at least sometimes to be articulated. Microsporogenesis may be simultaneous (Remizova et al. 2008b). The fruit opens along three lines as the three vascular bundles separate from the rest of the pericarp. Both integuments have two cell layers; the operculum is formed from enlarged cells of the inner integument. Starch deposition in tissues that will become perisperm begins before fertilization (Friedman 2008a).

There is some disagreement over the interpretation of the morphology of the embryo. Tillich et al. (2007) compared it with that of a monocot, describing collar rhizoids, a coleoptile, two cotyledonary sheath lobes, and a haustorium. Sokoloff et al. (2008a) suggested that the sheathing structure with its bilobed apex that is found in some species could be interpreted as two, more or less completely connate cotyledons. The seed attaches to the sheathing structure, although details of exactly how are unclear (or bifacial hyperphyll and unifacial hypophyll?!). In some taxa there is no sheathing structure at all and there is only a lateral outgrowth that goes into the seed. Sokoloff et al. (2008a) suggested that Hydatellaceae showed how monocot-like embryos/seedlings might have originated. Both Tillich et al. (2007) and Sokoloff et al. (2008a) examined largely surface morphology, neither looked in any detail at anatomy. Tuckett et al. (2010) found that differentiation of the embryo and appearance of the shoot and root occurred only after germination (note that any discussion of an "ancestral" embryo type for angiosperms must include discussion of Amborellaceae, at least!).

Some information is taken from Cutler (1969: vegetative anatomy), Hamann (1975, 1998 - embryology and general respectively), Cook (1983: germination), Hamann et al. (1979: seed anatomy), Rudall et al. (2007a: flower/inflorescence development), Remizova et al. (2008b: pollen), Friedman (2008a) and Rudall et al. (2008a), both embryology, Sokoloff et al. (2009a: growth patterns of the perennial species) and Taylor et al. (2010: pollination).

Classification. Sokoloff et al. (2008b) monographed the family.

Previous Relationships. Hydatellaceae have been considered to be monocots, albeit rather odd, and perhaps close to Poales-Centrolepidaceae (see above).

[Cabombaceae + Nymphaeaceae]: plant monopodial, rhizome/stolon elongated; hydroyzable [ellagi]tannins +; vessel elements in roots, with extensive fibrillar network in the end plates; pit membranes of tracheids with two thick layers of large fibrils; minute rhombic crystals on stellate cells [astrosclereids, stellate parenchyma cells]; leaves peltate, (divided), lamina vernation involute, 2ndary veins palmate, actinodromous, festoon brochidodromous, margin toothed, crenate or entire, (hydathodes +); flowers single; receptacle with cortical vascular system; P whorled, (outer [inner] whorls in 3's), outer members enclosing the rest of the bud; A whorled; tapetal cells multinucleate; pollen tube growth moderately fast; carpel margins with postgenital fusion, placentation ± laminar; parietal tissue ca 1 cell across; embryo sac very small relative to nucellus; exotesta with anticlinal walls sinuous; embryo suspensor 0 [?level].

Evolution. Divergence & Distribution. Fossils of Nymphaeaceae, Cabombaceae and/or stem-group Nymphaeales are known from the Lower Cretaceous from several parts of the world (e.g. D. W. Taylor et al. 2001, 2008; Mohr et al. 2008), and aliong with other angiosperms may have dominated aquatic habitats in Europe by the Albian (Sender et al. 2010). Although other fossils possibly of this group (to a certain extent characters of the two families are combined) are known from the Barremian-Aptian 125-113 million years before present in Portugal (Friis et al. 2001; see also von Balthazar et al. 2008 for another fossil perhaps assignable to this general [Nymphaeales-Austrobaileyales] area), they may also be from a member of Austrobaileyales (Gandolfo et al. 2004).

There has been much discussion over the timing of diversification within the Cabombaceae-Nymphaeaceae clade (e.g. Nixon 2008). Löhne et al. (2008) suggests that divergence is only Palaeocene in age, (75-)56.4(-38) million years ago, although Wikström et al. (2001) had found that divergence of the two families occurred 144-111 million years before present (in the latter study details of relationships within the clade differ from those given here, and of course Hydatellaceae were not included). Yoo et al. (2005) give a still younger date, pegging divergence within the crown group to only 44.6 ± 7.9 million years before present; the fossil Microvictoria was perhaps stem group Nymphaeales (cf. Gandolfo et al. 2004). D. W. Taylor et al. (2008, see also Taylor 2008) discuss the vegetative evolution of the group (see some of the characters above), noting how inclusion of diverse fossils affects relationships and hence evolutionary interpretations when carrying out analyses of morphological variation.

Chemistry, Morphology, etc. For micromorphological details of vessels and tracheids, see Carlquist and Schneider (2009) and Schneider et al. (2009); details of the wall structure of tracheids, at least, are very distinctive. Note that Carpenter (2005) described stomata as being largely variants of the actino/stephanocytic types; only one member of Cabombaceae was studied. Taylor (2008) outlined the vegetative morphology of this clade; Nymphaea s. str. appeared as monophyletic in a phylogenetic analysis of these characters, but without much support. Warner et al. (2008) discuss perianth evolution; they provide a useful summary on the literature on perianth morphology.

For information on anatomy, see Gwynne-Vaughan (1897), for root epidermis, see Voronkina (1974: ordinal characterisation above), for perianth venation, see Hiepko (1965b), for pollen morphology, see Osborn et al. (1991), for the development of the embryo sac, Orban and Bouharmont (1998), for the chloroplast inverted repeat, Graham and Olmstead (2000), for endosperm evolution, Floyd and Friedman (2001), for ovule development, see Yamada et al. (2001b), for root anatomy, see Seago (2002), for seed anatomy, see Collinson (1980) and Chen et al. (2004), for more on vessels and tracheids, see Schneider and Carlquist (2009a, b), and for general information, Les et al. (1999) and Schneider et al (2003).

CABOMBACEAE A. Richard   Back to Nymphaeales

Plant floating, rhizome/stem horizontal; alkaloids 0; stem vascular tissue with two pairs of bundles; internodes long; (leaves opposite), (lamina with semidichotomous venation); flowers rather small, parts whorled, (2)3(4)-merous; P two-whorled, tepaloid, members with single trace, (inner whorl somewhat delayed in development, with nectaries - Cabomba); A (3, 6), extrorse to latrorse, filaments moderately slender; tapetum more or less amoeboid; pollen (trichotomocolpate, tectum continuous, striate - Cabomba), endexine lamellate when young, not when mature; G (1-)3-18(-22), when 3/inner whorl of three ± opposite petals, stylar neck +, stigma terminal, capitate, (elongate - Brasenia); ovules 1-3(-5)/carpel, attached variously, outer integument semi-annular [hood-shaped], nucellar epidermal cells ± radially elongated, hypostase +; fruits follicles or achenes; hilum and micropyle sharing same opening in center of operculum; endosperm helobial [micropylar cell alone with free-nuclear division]; n = 40, 48, 52; germination?.

Cabombaceae

2[list]/6. World-wide, Brasenia schreberi subfossil remains show it to be far more widespread in Europe than at present (map: from Raymond & Dansereau 1949; Fassett 1953; Ørgaard et al. 1992; Hultén 1961; Fl. N. Am. III 1997; Löhne et al. 2008). [Photo - Brasenia Habit] [Photo - Flower.]

Evolution. Floral Biology & Seed Dispersal. Brasenia is wind pollinated, while Cabomba has paired nectaries on its inner tepals and is pollinated by flies; Taylor and Williams (2009) describe details of reproduction from pollination to fertlization in considerable detail.

Chemistry, Morphology, etc. The root endodermis has a Casparian strip and suberin lamellae. It is unclear how to interpret nodal anatomy. In Cambomba a trace leaves from each member of a vascular budle pair which shortly thereafter fuse commissurally, creating a nodal plexus; the foliar traces fuse and then divide, providing two petiolar bundles (Moseley et al. 1984). Brasenia has stems that are encased in a thick layer of mucilage; there are paired, glandular patches at the nodes. The peltate leaves are spirally arranged, although in some taxa they are uncommon; the more or less dichotomously-divided submerged leaves are opposite. There are five vascular bundles in the sepals and three vascular bundles in the petals of Cambomba, in both cases there is a single trace leaving the floral axis (Moseley et al. 1984). Stamens are sometimes physically close to each nectary and then they appear paired (Ørgaard et al. 1992). Pollen of Cabomba has striate exine. Although the endexine of mature pollen of Brasenia schreberi is not lamellate, it is laid down in plates (M. L. Taylor & Osborn 2006).

The granular infratectum of Podostemaceae has been compared with that of Cabombaceae; both are aquatics (Passarelli et al. 2002).

Some information is taken from Khanna (1965) and Batygina et al. (1982), both embryology, Richardson (1969: development of Brasenia flowers), Schneider and Jeter (1982: pollination of Cabomba), Williamson and Schneider (1993: general), Floyd and Friedman (2000: endosperm development), D. W. Taylor et al. (2001: fossils) and M. L. Taylor et al. (2008: esp. pollen).

Synonymy: Hydropeltidaceae Dumortier

NYMPHAEACEAE Salisbury   Back to Nymphaeales

Perennials (annuals); myricetin, sesquiterpene [pseud]alkaloids; a root arises below each leaf; stem vascular tissue complex, (in concentric rings), axial bundles concentric; astrosclereids +; nodes 3:3; stipules adaxial or none; flowers and buds not in normal axillary position [often replace leaf in spiral]; flowers large; P members usu. with sepaloid and petaloid areas, (0- [some Ondinea])4-many; A many, often whorled, laminar, staminodes +, next to G (also next to P), (filaments stout), connective produced or not; tapetum both glandular and amoeboid; microsporogenesis simultaneous, pollen trinucleate, (zona-aperturate), ektexine homogeneous-granulate, (no exine), (endexine lamellate); G laterally connate only, whorled and star-like, margin fusion also postgenital, stigma dry; ovules (3-)many/carpel, not filling the locule, (straight), outer integument also cap-shaped [annular]; fruit baccate; (exotesta not palisade; anticlinal walls not sinuous); endosperm scanty, embryo green or white, plug-like, cotyledons basally connate or not.

Nymphaeaceae

3[list]/58. World-wide (map: from Vester 1940; Wickens 1976; Hultén 1961; Heywood 2007; Löhne et al. 2008). [Photo - Leaf, Flower.]

1. Nupharoideae Ito

Rhizomes stout, horizontal, creeping; roots with 10-18 xylem poles, pith large; bracts +; P members 1-veined, K 5-14, spiral, outer greenish, inner tepals [= petals] many, scale-like, somewhat delayed in development; nectary on abaxial surface of inner tepals; pollen spiny, tectum continuous, trinucleate; G 5-23(-36); outer integument 4-6 cells across, parietal tissue ca 2 cells across, nucellar cap ca 4 cells across, hypostase, postament +; fruit emergent; n = 17.

1/11. North Temperate.

Synonymy: Nupharaceae A. Kerner

2. Nymphaeoideae

(Rhizome short, erect); roots with 5-9 xylem poles, pith at most small; inner satellite peduncle bundle +; bracts 0; hypanthium ± developed; P members 3-veined, K 4-5, spiral, (C 0); staminodes showy, (larger peripheral A with three traces); pollen with encircling sulcus (inaperturate), surface various, inc. tectum continuous, (trinucleate); G 3-many, more or less inferior [A alone on top of G, K and "C" also often on top; A also adnate to "C"], with inter-carpel septal slits, floral axis projecting in the middle [not Barclaya], stigmatic surface continuous, extragynoecial compitum +; ovules (straight - Barclaya), (micropyle bistomal), (outer integument to 20 cells across - Euryale), (parietal tissue 3-4 cells across - Victoria); fruit maturation underwater; seeds arillate (not, but spiny - Barclaya), (exotesta cells cuboid - Euryale); n = 10, 12, 14-18.

2/48: Nymphaea (46). World-wide.

Synonymy: Barclayaceae H.-L. Li, Euryalaceae J. Agardh

Evolution. Divergence & Distribution. The family was previously much more diverse, with distinctive seeds with a micropyar and palisade exotesta with sinuous anticlinal walls that can be assigned here being common in the Cretaceous (Friis et al. 2009b for references). The Late Aptian/Early Albian Cretaceous Monetianthus, from Portugal, is embedded in Nymphaeaceae (Friis et al. 2009b). Microvictoria, a somewhat later fossil from the Turonian ca 90 million years before present and found in New Jersey, U.S.A., is very like Victoria (= Nymphaea). Victoria has "paracarpels" immediately surrounding the gynoecium, and these are also found in Microvictoria; indeed, this latter is like flowers of Victoria in almost all respects, except being less than 1/10th the size (Gandolfo et al. 2004, see also above [Cabombaceae + Nymphaeaceae] for early Cretaceous possibly nymphaeaceous flowers and leaves).

Although the family is widespread and probably very old, individual clades within it are relatively localized, and crown group diversification probably occurred in the northern hemisphere as late as the early Tertiary (Löhne et al. 2008).

Plant-Animal Interactions. Nymphaeaceae are host plants of reed beetles, Chrysomelidae-Donaciinae (see also Poales: Kölsch & Pedersen 2008: much discussion on the age and evolution of the group). Interestingly, Enterobacteriaceae near Buchnera are believed to produce the material that makes up the cocoon that characterises Donaciinae, a group that is also noted for the ability of the larvae to grow under water (Kölsch & Pedersen 2010).

Floral Biology & Seed Dispersal. Thermogenesis has been detected in the flowers of some Nymphaeaceae (Seymour 2001; Seymour & Matthews 2006). Beetles and a variety of other insects may be pollinators (e.g. see Padgett 2007). Scarab beetles (Cyclocephalini) may have pollinated night-flowering water lilies for some 100 million years, pollinating species both in America, where the beetles are common, and in Africa, where the beetles are otherwise very uncommon (Ervik & Knudsen 2003). The distinctive flowers of Ondinea, wind pollinated, are derived from Nymphaea-type flowers (Löhne et al. 2009). Schneider (1979) summarizes information about the pollination biology of the family.

The progamic phase, the time between pollination and fertilization, is notably short, up to a mere 8 hours, as in at least some other aquatic angiosperms (including Nelumbo: see Williams et al. 2010).

Dehiscence of the fruit of Nymphaeaoideae is by swelling of the mucilage inside it, whereupon the wall splits irregularly.

Chemistry, Morphology, etc. The root endodermis has a Casparian strip. There are sometimes sclerenchymatous diaphragms in the pith. The vasculature of the stem is exceedingly complex, especially at the node, with peduncular complexes forming internally, however, basic stem structure is unlike that of monocotyledons; the primary xylem is mesarch (Weidlich 1980 and references). Schneider et al. (2008, 2009) and Schneider and Carlquist (2009) discuss stem tracheids and root vessels, emphasizing the rather arbitrary distinction between vessels and tracheids. The astrosclereids of Nuphar and Nymphaea, at least, have calcium oxalate crystals in the walls (Fink 1991). Stipules may be adaxial and bicarinate or paired and lateral.

In both Nuphar and Nymphaea flowers and even branches may replace leaves in the genetic spiral (e.g. Groß et al. 2006); within the flowers themselves, however, parts are generally whorled (e.g. ). Yoo et al. (2010) discuss the evolutionary/developmental relationship between sepals and petals; see also Doyle and Endress (2011), who suggest that Nuphar has both tepals and petals. Schneider (1976) and Moseley and Uhl (1985) note that the vascular suppy to perianth and androecial members consists of two radially associated bundles. In Euryale the filaments are quite slender and are basally adnate to the staminodes; it is unclear if it has free nuclear endosperm (Floyd & Friedman 2001 - see also Kanna 1964, 1967 for endosperm development in the family). Weberling (1989) suggested that in at least some Nymphaeaceae the individual carpels were free laterally, if adnate to the central axis inside and to "hypanthial" tissue outside (see also von Balthazar et al. 2008). Zhou and Fu (2008) found that at anthesis, but not before or after, the micropyle of Nuphar was bistomal, not endostomal. Weberling (1989) also described how in Nuphar axial tissue separates from the gynoecium when the fruits are ripe, so exposing the basically free carpels; if this is correct (but it seems rather unlikely), its gynoecium would be very similar to that of other Nymphaeaceae; Padgett (2007) described dehiscence as being along lines in the septal and ovarian walls where aerenchymatous tissue had developed. The seedling axis of some species of Nymphaea have a lateral projection.

Some information is taken from Schneider and Williamson (1993: general); Takhtajan (1988) provides much information on ovules and seeds, Khanna (1964, 1967) described embryology (8-nucleate embryo sacs...), Tillich (1990) information on seedling morphology, Shamrov (1998) on the ovule of Nuphar, Floyd and Friedman (2001) on endosperm development, and Yao et al. (2004) some information on pollen morphology.

Phylogeny. Liu et al. (2005) provide an ITS phylogeny of the family, but with some rather surprising relationships - Nuphar [Cabomba + Brasenia] [Nymphaea [Euryale + Victoria]]. Nelumbo, which was included in the analysis, did at least stay outside this clade... For a phylogeny of Nymphaea, see Borsch et al. (2007); the genus definitely includes the wind-pollinated and usually apetalous Ondinea, but some relationships lacked much support, e.g. the position of [Euryale + Victoria] as sister to Nymphaea s.l. However, in a study with more complete sampling the spiny Victoria and Euryale are also embedded in Nymphaea sensu lato, as of course is Ondinea (Löhne et al. 2007, 2009; Borsch et al. 2008).

Taxonomy. For a revision of Nuphar, see Padgett (2007).