EXTANT SEED PLANTS

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

MAGNOLIOPHYTA

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

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

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

Evolution. Soltis et al. (2008: a variety of estimates) give the age of this clade as 180-132 million years; Magallón and Castillo (2009) offer very different ages - ca 229 million years for relaxed and 127 million years for constrained penalized likelihood datings.

Presence of vesels is optimised here, however, given their apparent absence in Hydatellaceae and distinctive morphology in other Nypmphaeales (Carlquist & Schneider 2009; Schneider & Carlquist 2009), they may have arisen twice in this part of the tree. That is, they would be an apomorphy both for [Camcombaceae + Hymphaeaceae] and for [Austrobaileyales [[Chloranthales + Magnoliids] [monocots [Ceratophyllales + Eudicots]]]]. Indeed, 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, it would seem unlikely for vessels to have evolved in aquatics. Sperry et al. (2007) discuss other 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. 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. (2009); 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 rhizomatous herbs; 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 closed bundles; protoxylem lacunae +; secondary thickening 0; nodes?; aerenchyma common; stomata anomocytic; leaf base broad; bracts 0; pollen boat-shaped, tectum continuous; P persistent; seeds operculate, exotestal, ± palisade, hilum outside operculum; endosperm scanty, first division transverse, chalazal cell undivided, ± enlarged, endosperm from micropylar cell, perisperm copious [starchy], precocious, cells ± multinucleate, suspensor 0, embryo broad; germination hypogeal; intergenic inversion in chloroplast inverted repeat. - 3 families, 6 genera, 74 species.

Evolution. Soltis et al. (2008: a variety of estimates) suggest an age of divergence of the Nymphaeales from other angiosperms as 180-132 million years ago; Wikström et al. (2001) suggested an 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 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 ca 124 million years old, has recently been linked with Hydatellaceae (Doyle & Endress 2007; Doyle 2008b), although they have little in common interms of overall appearance. Morphological analyses place the Early Cretaceous Monetanthus embedded in Nymphaeaceae (Friis et al. 2009), in which case its distinctive reticulate-perforate pollen is independantly derived 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, Hydropeltidales Spenner - Nymphaeanae Reveal - Nymphaeidae Takhtajan - Hydropeltopsida Bartling, Nymphaeopsida Horaninow

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

Plant sympodial, rhizome erect; chemistry?; vessels 0; leaves linear, with a single vein; plant monoecious; inflorescence axillary, scapose, capitate, with involucral bracts, (sessile); flowers imperfect; P 0; staminate flowers: A 1, filaments long, slender, endothecium 0, tapetal cells?, pollen with spinules; carpellate flowers: G 1, three vascular bundles equidistant, with 1 pendulous anatropous apotropous ovule, micropyle bistomal, ovule tenuinucellate, nucellar cap +, semi-annular [hood-shaped] outer integument, stigma penicillate, of rows of plump cells; fruit dehiscent or and 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).

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.

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, and Sokoloff et al. (2009a: growth patterns of the perennial species).

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; 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 involute, peltate, (divided), 2ndary veins palmate, actinodromous, festoon brochidodromous, margin toothed or entire; flowers single along stem, with cortical vascular system; P whorled (outer [inner] whorls in 3's), outer members enclosing the rest of the bud; A whorled, pollen tube growth moderately fast, placentation ± laminar, carpel margins with postgenital fusion; anticlinal walls of exotesta sinuous; suspensor 0 [?level].

Evolution. 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). 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 have been considerable arguments over the timing of diversification within Nympahaeales and Nymphaeaceae (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 appeared to occur 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 as suggested by analysis of morphological variation and hence evolutionary interpretations.

Chemistry, Morphology, etc. 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 vessels and tracheids, see Carlquist and Schneider (2009) and Schneider and Carlquist (2009a, b), and for general information, Les et al. (1999) and Schneider et al (2003).

CABOMBACEAE A. Richard   Back to Nymphaeales

Floating and rhizomatous, rhizome/stem horizontal; alkaloids 0; stem vascular tissue with two pairs of bundles; internodes on stems long; leaves (opposite, with semidichotomous venation); flowers rather small, parts whorled, (2)3(4)-merous; P two-whorled, (tepaloid - Brasenia), members with single trace, (subequal; with nectaries); A (3, 6), extrorse to latrorse, filaments 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 ± opposite petals [Cabomba], 1-3(-5) ovules/carpel, attached variously, outer integument semi-annular [hood-shaped], stylar neck +, stigma terminal, capitate, (elongate - Brasenia); fruits follicles or achenes; hilum and micropyle sharing same opening in center of operculum; endosperm helobial [micropylar cell 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. 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 Richardson (1969: development of Brasenia flowers), Schneider and Jeter (1982: pollination of Cabomba), Williamson and Schneider (1993: general), Floyd and Friedman (2000: embryo sac), D. W. Taylor et al. (2001: fossils) and M. L. Taylor et al. (2008: esp. pollen).

Synonymy: Hydropeltidaceae Dumortier

NYMPHAEACEAE Salisbury   Back to Nymphaeales

(Tuberous) perennials, stem not floating; a root arises below each leaf; myricetin, sesquiterpene [pseud]alkaloids, hydrolyzable [elagi-]tannins +; 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 often whorled, laminar, staminodes inside (outside), (filaments stout), connective produced or not; tapetum both glandular and amoeboid; microsporogenesis simultaneous; pollen trinucleate, ektexine homogeneous-granulate, (no exine), (endexine lamellate); G laterally connate only, whorled and star-like, margin fusion also postgenital, (3-)many (atropous) ovules/carpel, not filling the locule; outer integument variable; stigma dry; fruit baccate; (exotesta not palisade; anticlinal walls not sinuous); 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; nectary on abaxial surface; pollen spiny, tectum continuous, trinucleate; G 5-23(-36); fruit emergent; n = 17.

1/11. North Temperate.

Synonymy: Nupharaceae A. Kerner

2. Nymphaeoideae

Rhizomes?; roots with 5-9 xylem poles, pith at most small; inner satellite peduncle bundle +; P members 3-veined, K 4-5, spiral, (C 0), staminodes showy, (larger peripheral A with three traces); pollen zonasulcate (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; ovules (straight - Barclaya), micropyle bistomal, (outer integument to 20 cells across - Euryale); 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. The family was previously much more diverse, with seeds with a micropyar and palisade exotesta with sinuous anticlinal walls being common in the Cretaceous (Friis et al. 2009 for references). The Late Aptian/Early Albian Cretaceous Monetanthus, from Portugal, is embedded in Nymphaeaceae (Friis et al. 2009). 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 for early Cretaceous possibly nymphaeaceous flowers). Although the family is widespread, individual clades within it are relatively localized, and crown group diversification probably occured in the northern hemisphere in the early Tertiary (Löhne et al. 2008).

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 in fact derived from Nymphaea-type flowers (Löhne et al. 2009).

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. ). 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). 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, Tillich (1990) on seedling morphology, 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. However, in a study with more complete sampling the spiny Victoria and Euryale - they are sister taxa - 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).