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, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem complex; 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 spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral, veins -5(-8) mm/mm²; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, 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, 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 [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 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, development in general centripetal, numbers unstable, P not 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, exine columellar, endexine thin, compact, lamellate only in the apertural regions, pollen germinating in less than 3 hours, tube elongated, growing at 80-600 µm/hour, with callose plugs and callose-based walls, penetrating between cells, siphonogamy, penetration of ovules within ca 18 hours, distance to first ovule 1.1.-2.1 mm, 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, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, hollow, 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; 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.

CUCURBITALES + FAGALES: ovary inferior; fruit 1-seeded, indehiscent.

See also Endress and Matthews (2006) for additional features perhaps characterising this group - these include an inferior, three-carpellate gynoecium. Imperfect flowers pervade both orders.

FAGALES Engler  Main Tree, Synapomorphies.

Ectomycorrhizae common; Frankia infection via root hairs; (flavononols), dihydroflavonols, ellagic acid +; (cork cambium outer cortical); vessel elements also with scalariform perforation plates; sieve tubes with non-dispersive P-protein bodies; bud scales +; leaf margins toothed, 2ndary veins proceeding straight to non-glandular teeth and higher-order veins convergent on those teeeth [urticoid]; plants monoecious, inflorescence a spike or catkin, flowers in compact cymose clusters, very small; P +, A opposite P, tectum ± spinulate, granular layer below tectum, nectary 0, 2 pendulous unitegmic ovules [with nucellar cap?]/carpel, poorly developed at pollination, integument 3-10 cells across, fertilisation delayed, style undivided, but ± 0, stigma ± decurrent, linear, dry; fruits dry; testa vascularised, not mechanical, exotesta often enlarged and persisting; cotyledons large. - 8 families, 55 genera, 1877 species.

The pollen of Betulaceae, Rhoipteleaceae and Juglandaceae, and to a lesser extent that of Fagaceae, is rather like that of the Normapolles type abundant in the Turonian-Campanian of the Cretaceous, some 98-94 million years before present (Kedves 1989; Friis et al. 2003a, 2006a for a summary; Crepet et al. 2004 for a list of early records of Fagales fossils). Normapolles pollen is oblate in shape (i.e. it is a radially symmetrical grain in which the polar axis is shorter than the equatorial diameter) and triaperturate with protruding, elaborate and strongly thickened aperture regions, the apertures themselves often being formed from expansions of the granular infratectal layer (and hence the pollen is triangular in transverse section). The apertures have internal pores and externally short colpi or pores. The wall is usually tectate-granular, but sometimes with an atectate polar zone, the surface being almost smooth to finely spinulate to rugulate (details from Friis et al. 2003a). Fossil flowers producing pollen of the Normapolles type are perfect, rarely imperfect (cf. extant Fagales), and with a simple, undifferentiated perianth. However, the pollination, at least, in fossil taxa assigned to Fagales (the fossils are ca 84 million years old - see Herendeen et al. 1999) may have been somewhat different from that of the extant members. Thus Antiquacupula appears to have nectaries at the base of the stamens (Sims et al. 1998; Herendeen et al. 1999). Other details of the the morphology of some of these fossil flowers are also distinctive. Normanthus, from the late Cretaceous of Portugal, has perfect flowers with five perianth members that alternate with the stamens, there are two collateral carpels with separate and quite long styles, and the placentation is described as being parietal (Schönenberger et al. 2001b). Endressianthus has imperfect flowers, and in the staminate flowers the stamens alternate with the tepals; Dahlgrenianthus has perfect flowers and a superior ovary with more or less separate styles (Friis et al. 2006a); while Archaefagacea has a tricarpellate gynoecium, two ovules per carpel and sometimes three-seeded fruits. Schönenberger et al. (2001b) and Friis et al. (2003a) give useful tables comparing the morphology of extant and fossil members of the order.

Wind pollination and monoecy now pervades the order (but cf. some fossil Fagaceae!). Delayed fertilisation, chalazogamy, and also intermittent pollen tube growth (e.g. Sogo & Tobe 2005, 2006a, b, d [the last for a summary]) are also common, although chalazogamy itself is perhaps unlikely to be plesiomorphic in the order (the situation is unknown for Nothofagaceae, Fagaceae are porogamous). Delayed fertilisation is associated with the immaturity of the ovules at pollination and competition between the ovules, indeed, in Corylus avellana the ovules do not even begin to develop until after pollination (Germain 1994). Fagales are hardly particularly speciose (e.g. Magallón & Sanderson 2001), but members - especially of Fagaceae - can dominate the forests in which they grow. Lycaenidae caterpillars are quite commonly to be found on members of this order (see Fielder 1991). Phyllonorycter leaf-mining moths (Lepidoptera - Gracillariidae - Phyllocnistinae) are especially speciose on Fagales, about half the known host records being from this group (Lopez-Vaamonde et al. 2003). However, diversification seems to have occured in the region of 50.8-27.3 million years before present, well after the order itself originated (see above), and after the leaf-miner clade itself evolved, some 76.3-50.3 million years before present (Lopez-Vaamonde et al. 2006). Both Heterobathmidae (Nothofagaceae) and Eriocraniidae (Fagaceae, Betulaceae), clades rather "basal" in the lepidopteran tree, are found on Fagales (Shields 1988). Rusts on Fagales are predominantly to be placed in Pucciniastraceae, also found on ferns (Savile 1979). A particular Frankia clade involved in nitrogen fixation is restricted to Fagales, although members of another clade are also to be found here (Clawson et al. 2004).

The leaf teeth in Juglandaceae, Rhoipteleaceae and Myricaceae are intermediate in "type", having a ± splayed, (non)glandular apex, and the main tooth vein is joined by branches that leave below, or one of the branches may proceed above the tooth (Hickey & Taylor 1991). Although the tepals are small, they may have three traces (and in fosil taxa). Integument number is variable. Germination is often both hypogeal and epigeal in the one family, but not in Casuarinaceae and Nothofagaceae.

Fagales are the core of the old "Englerian" Amentiferae which have since been comprehensively demolished, members finding resting places among many otherwise entirely unrelated groups within the Eudicots such as Malpighiales (Salicaceae), Proteales (Platanaceae), and Rosales (Ulmaceae and relatives: e.g. Qiu et al. 1998). In the late 19th century and early twentieth century in particular, a number of botanists thought that Amentiferae were primitive, and the chalazogamy common in the order was even thought to be intermediate between fertilisation in some gymosperms and the porogamy that characterises most angiosperms (e.g. Nawaschin 1895). There are no immediate relationships with hamamelid taxa such as Altingiaceae and Hamamelidaceae (see Saxifragales here) that were previously thought to be intermediate between Amentiferae and more conventional broad-leaved angiosperms. Fagales comprise the Faganae and two and a half other superorders in Takhtajan (1997).

The relationships within Fagales are becoming fairly well resolved (see tree), although the position of Myricaceae remains somewhat uncertain. Details can be found in Manos and Steele (1997), D. Soltis et al. (2000a: Rhoiptelea not included) and Li et al. (2002). Manos and Steele (1997) show Myrica as immediate sister to Betulaceae, etc., in a matK and combined matK + rbcL analysis, although support was weak, but sister to all Fagales except Nothofagaceae and Fagaceae in a rbcL analysis, the latter set of relationships also being found by Li et al. (2002) using trnL-F sequence data, but with only 61% bootstrap support. Li et al. (2004: six genes, all three genomes) found Myricaceae to be sister to [Juglandaceae + Rhoipteleaceae], although the support still was not strong; the tree here follows the topology in this last paper. Herbert et al. (2006: three genes) find the same set of relationships, but with little support for the position of Myricaceae.

For cork cambium initiation, see Weiss (1890); flower and inflorescence morphology, see Abbe (1974): chemistry, see Giannasi (1986); pollen, Zavada and Dilcher (1986); vegetative morphology, Hickey and Taylor (1991); pollen, Feur (1991); embryology, Xing et al. (1998); and fossils, Friis et al. (2003a and references).

Includes Betulaceae, Casuarinaceae, Fagaceae, Juglandaceae, Myricaceae, Nothofagaceae, Rhoipteleaceae, Ticodendraceae.

Synonymy: Juglandineae Thorne & Reveal, Myricineae Thorne & Reveal - Betulales Bromhead, Casuarinales Lindley, Corylales Dumortier, Juglandales Dumortier, Myricales Engler, Nothofagales Doweld, Quercales Burnett, Rhoipteleales Reveal - Casuarinanae Reveal & Doweld, Faganae Takhtajan, Juglandanae Reveal

NOTHOFAGACEAE Kuprianova   Back to Fagales

Chemistry?; sclereid nests?; peltate glandular hairs +; leaves two-ranked (spiral), vernation various, margins also entire, stipules usu. peltate (0? - N. obliqua), enclosing colleters; staminate flowers: P connate, uniseriate, A 10-15(-many), basifixed, connective usu. produced, pollen 3-10-colpate, aperture margins raised, columellae 0; carpellate flowers: 1-3 together, P in 1 cycle, (A hairy), G [2-3], median member abaxial, chalazogamy?, (short undivided style +); cupule (2-)4-valved, lamellate (0), fruits (1) 3(-7), lenticular (central) or triangular; testa?; endosperm initially nuclear, cotyledons folded; n = 13.

1/35. New Guinea to South America (Map: Good 1974, sl. modified). For checklist and bibliography, see Govaerts and Frodin (1998: in Fagaceae). [Photo - Branch]

For the biogeography of Nothofagus, a much-discussed subject, see Swenson et al. (2001) and Knapp et al. (2005). The family is perhaps 90 million years old, and the current distribution of the genus has often been explained by vicariance, i.e. continental drift; fossils of all four subgenera are known from the Late Campanian in Antarctica (Swenson et al. 2001). However, Knapp et al. (2005) suggest that Nothofagus reached New Zealand, at least, by long distance dispersal only ca 30 million years before present (see also Waters & Craw 2006). The rust parasites of Nothofagaceae are rather different to those of other Fagales (Savile 1979). The inaperturate discomycete Cyttaria is found on Nothofagus in both the Antipodes and in South America, but not in New Guinea. Humphries et al. (1986: this work needs to be re-evaluated in the context of recent ideas of relationships) discuss the parasites and associates of Nothofagus, and suggest the possibility of some coevolution of the genus with Eriococcus scale insects that grow on it; the moth Heterobathmia, a genus perhaps 125 million years old, part of a clade (Micropterigidae) sister to all other Lepidoptera, makes its home exclusively on Nothofagus, both as an adult (it has jaws, and eats pollen) and as a larva (see also Futuyma & Mitter 1996).

Unlike Fagaceae, there is no obvious relationship between the number of fruits and the number of valves of the cupule. The central flower of the cupule often has two carpels, lateral flowers have three. Flowers that apparently have many stamens are interpreted as being the result of fusion of dichasia, so they are pseudanthia (see also Betulaceae). Nothofagus obliqua may have unilacunar nodes.

Nothofagus has often been included in Fagaceae, as by Cronquist (1981) and Kubitzki (1993b).

Further information may be found in Poole (1952), Hegnauer (1989, as Fagaceae: chemistry), Philipson and Philipson (1979, 1988), Hill and Jordan (1993, Kubitzki (1993b: general), Manos (1997: relationships), and Rozefelds (1998) and Rozefelds and Drinnan (1998: stamens and staminate flowers).

Fagaceae [Myricaceae [Juglandaceae + Rhoipteleaceae]] [Casuarinaceae [Ticodendraceae + Betulaceae]: leaves spiral; anthers dorsifixed.

FAGACEAE Dumortier, nom. cons.   Back to Fagales

Hairs often stellate/branched; sclereid nests with rhomboidal crystals in bark; stomata also cyclocytic; leaves (two-ranked, whorled), conduplicate-plicate, (margins entire, lobed; biserrate); inflorescence branched or not, spicate; flowers often trimerous, P biseriate [thus = T] or not, 4-6 (7)-lobed; staminate flowers: bract, A 4-20 (connective produced), pollen not spiny, granular layer below tectum 0, pistillode +; carpellate flowers: staminode +, G [(2) 3-6(-15)], alternating with P, or median member abaxial, ovules (uni)bitegmic, epitropous, micropyle bistomal, elongate [Fagus], (nucellar tracheids +); cupule of valves [one more than fruit number], ± spiny, fruit nut-like, trigonous; endocarp hairy inside; seed pachychalazal; (endosperm cellular); n = 12 (13, 21).

7[list]/670 - 2 subfamilies below. More or less worldwide (Map: from Soepadmo 1972; Fl. N. Am. III. 1997). For checklist and bibliography, see Govaerts and Frodin (1998).

1. Fagoideae K. Koch

Ellagic acid 0; inflorescence capitate; staminate flowers: pollen exine fine scabrate; carpellate flowers: stigma capitate; cotyledons folded; germination epigeal.

1/10. Temperate N. hemisphere. [Photo - Fruiting Branch © M. Brand.]

2. Quercoideae Õrsted

Inflorescence spike or catkin, staminate and carpellate flowers on separate inflorescences or not; staminate flowers: pollen exine scabrate, verrucate, rugulate or smooth, anastomosing-striate, (pistillode secreting nectar), stigmas capitate, decurrent, or punctiform and with a terminal pore; cupule also cup-shaped, with scales; fruit also rounded; germination hypogeal or epigeal.

6/640: Quercus (400: fast-maturing acorns and pericarp glabrous inside - probably derived characters - or acorns take 1 1/2 years to develop, endocarp hairy inside), Lithocarpus (120: fruits like those of Quercus), Castanopsis (110). N. temperate, at higher elevations in the tropics, not S. Africa or New Zealand, barely in Australia. [Photo - Fruit]

Trigonobalanus (on Fraser's Hill in Peninsula Malaya, but described only some 35 years ago from Mt Kinabalu in Borneo, found in S. America 15 years ago, then from fossils in N. America, the three extant species placed in three genera, but forming a single clade (Nixon & Crepet 1989 for information)...

Recent studies (Oh & Manos 2006, 2008) suggest that Lithocarpus is polyphyletic, the South East Asian members grouping with Chrysolepis, the single species, L. densiflorus, from West North America (the California floristic province) with Quercus, Castanopsis, and Castanea. For phylogenetic relationships within Quercus, see Manos et al. (1999) and Oh and Manos (2008); New and Old World species are in separate clades.

Synonymy: Quercaceae Berchtold & Presl

• The family is readily recognisable in fruit. The distinctive cupules enclose one to three fruits, and the seed itself is often surrounded by dense hairs coming from the endocarp. The outer surface of the wood is characteristically furrowed, and the inflorescences are erect to pendant, spicate to catkinate. The leaves are usually spirally inserted, serrate (if entire the venation is camptodromous), and rather leathery, and the hairs are stellate or branched.

Castanea dentata, previously the dominant large tree in extensive areas of forest in eastern North America, has been utterly devastated by the ascomycete fungus Endothea parasitica, although trees may persist for some time after infection by suckering. Theclines (Lycaenini) are commonly found on this family (Ehrlich & Raven 1964). Fertilisation is porogamous, according to Johri et al. (1992), although it is much delayed (Sogo & Tobe 2006d and references). Quercoideae such as Castanea and Castanopsis are insect pollinated.

There has been infinite discussion over the morphological nature of the small protrusions surrounding the ovary, and the whole complex is often interpreted as a modified cymose inflorescence (e.g. Sims et al. 1998; Manos et al. 2001a; Pigg et al. 2001; Oh & Manos 2008 for references). When the cupule has valves, probably the plesiomorphic condition, there is one valve more than the number of fruits. Oh and Manos (2006, 2008) suggest that the cup-shaped cupule, which may be continuous, scaly or spiny, that encloses a single, rounded fruit has evolved more than once within Quercoideae.

Some fossil taxa have a very different morphology to that of extant representatives, see e.g. the staminate and perfect flowers of Antiquacupula where there are also suggestions of nectary lobes between the stamens, the pollen has a perforate tectum, and the inner walls of the fruit loculi are glabrous (Sims et al. 1998). Flowers of Antiquacupula have P 3 + 3, A 12, G 3, the outer whorl of six stamens being opposite the tepals, the inner whorl alternating with them (Sims et al. 1998). The oldest fossils assignable to the family may be from some 90 million years before present (Crepet et al. 2004 for references).

For intergeneric and -subfamilial graft hybrids, see Herrmann (1951). For the orientation of the carpels, see Endress (1977a), where the median member of outer P whorl in both staminate and carpellate flowers is shown as being abaxial, cf. Sims et al. (1998). Fertilisation is porogamous, according to Johri et al. (1992), although it is much delayed (Sogo & Tobe 2006d and references). The outer integument is vascularised.

Fagus is sister to rest of Fagaceae (Manos et al. 1993); Quercoideae s. str. are paraphyletic, and Trigonobalanus is sister to the rest of Quercoideae + Castaneoideae, which are here combined as Quercoideae.

See also Hegnauer (1966, 1989: chemistry), Axelrod (1983: distributional history), Nixon (1989), and Kubitzki (1993b: general) for information. For phylogeny, character evolution, and biogeography of the family, see e.g. Manos and Stanford (2001) and Manos et al. (2002). Govaerts and Frodin (1998) provide a checklist and bibliography for the whole family.

[[Myricaceae [Juglandaceae + Rhoipteleaceae]] [Casuarinaceae [Ticodendraceae + Betulaceae]]]: myricetin +; pollen pororate, G [2]; fertilization chalazogamous.

At what level should "archesporium multicellular" be placed? Several features of wood anatomy, including the presence of chambered crystals in the axial parenchyma (although this may properly be a feature of Fagales as a whole), are also common in the group (Carlquist 2002c). A number of taxa have pollen walls with small granules clustered around the aperture near the inside (Feuer 1991).

[Myricaceae [Juglandaceae + Rhoipteleaceae]]: chains of crystal-containing cells in the wood; sieve tube P-protein bodies 0; peltate glandular hairs +; stipules 0; 1 flower/bract; ovule single [per flower], straight [atropous], stigma lamellular/laciniate.

The evolution of features of inflorescence and ovule is particularly difficult to understand; they could be synapomorphies of the clade as a whole (as above), or be independent apomorphies of Myricaceae and Juglandaceae. Herbert et al. (2006) discuss possible synapomorphies of this clade.

MYRICACEAE Kunth, nom. cons.   Back to Fagales

Roots often with N-fixing Frankia, rootlets clustered, of limited growth [Proteoid roots]; nodes also 1:1; leaves (pinnatifid), conduplicate to curved, stipules 0 or ?foliaceous, lobed [Comptonia]; plants dioecious or monoecious; one flower/bract; P 0 (6-lobed - Canacomyrica), staminate flowers: A 1-8(-20) (opposite P); carpellate flowers: (staminodes + - Canacomyrica), G [(3)], ?superior to inferior, ovule basal, straight [atropous], (bitegmic, ?micropyle - Canacomyrica), fertilisation porogamous; fruit a drupe; seed ?pachychalazal, testa ± thickened; n = 8, 12.

3[list]/57: Myrica (55: some species change "sex"). ± Cosmopolitan, including New Caledonia but not Australia (Map: Hultén 1958; van Balgooy 1974). [Photos - Collection.]

• Myricaceae are woody plants recognisable by the aromatic glands that cover the plant coupled with the spiral, simple, rarely deeply lobed leaves.

Although fertilisation is porogamous, it is delayed as in other Fagales, the growth of the pollen tubes as it were pausing on the nucellar surface; this method of fertilization, described as pseudoporogamy, may be derived (Sogo & Tobe 2006a, b).

Bracteoles may be present or not. Although the ovary appears to be superior, as in Comptonia, it is often so highly reduced that any traces of its inferior construction would be lost, however, in Canacomyrica, from New Caledonia, staminodes are borne on top of the ovary and there is a six-lobed perianth. In some species of Myrica the ovary is invested by tissue from a meristem developing below the flower, even below the bracteoles, which are then borne on the flower. The flowers of Canacomyrica have three "bracts" (Herbert et al. 2006) - floral bract + bracteoles/prophylls? Kubitzki (1993b) draws the ovule of Canacomyrica as being basal, straight [atropous], and with a much elongated integument forming an apical tube; Herbert et al. (2006) simply describe the ovules as being bitegmic.

For chemistry, see Hegnauer (1969, 1990), for the staminate flowers, see Macdonald (1978), for general information, see Kubitzki (1993b), and for wood anatomy, see Carlquist (2002c).

Synonymy: Canacomyricaceae Doweld

Juglandaceae + Rhoipteleaceae: leaves odd-pinnate; P 4; endosperm 0; x = 16.

Including Rhoipteleaceae in Juglandaceae s.l. is optional in A.P.G. II.

For karyomorphology, see Oginuma (1999).

JUGLANDACEAE Perleb, nom. cons.   Back to Fagales

Flavones, napthoquinones, raffinose and stachyose [phloem exudate] +; nodes also 5:5; leaves spiral, leaflets subopposite, (involute or ± conduplicate [Alfaroa]; margins entire); (inflorescence branched), one flower/bract, bracts and/or bracteoles ± adnate to flower or not, (P 0-3); staminate flowers: A 2-many, opposite P, pollen porate, apertures usu. elongate, pistillode +; carpellate flowers: G [(3, 4)], median or transverse, median member adaxial, apically 1-locular, loculi often divided [false septae], ovule erect, born at the top of the incomplete septum, (fertilisation porogamous), (stigmas not decurrent); fruit drupaceous, nut, samaroid, or winged by persistent bracts, pericarp intrusive; seed large, pachychalazal, cotyledons much folded.

7-10[list]/50 - 2 groups below. North temperate, S. to Argentina and Malesia. [Photo - Collection]

1. Engelhardioideae Iljinskaya

Leaf parenchyma with druses [basal - none]; buds lacking scales; leaves (opposite), even-pinnate, leaflets usu. entire; bracts 3-lobed, bracteoles 0-2, adnate to lower half of ovary; nuts with a layer of fibrous cells.

3-4/14. Himalayas to Malesia, Mexico to Colombia (Map: see Meusel et al. 1965; Manchester 1987).

Platycarya is distinctive in having cone-like infructescences, male and female flowers are in the same spike, bracts are not part of the fruit, the sticky pollen and strongly scented flowers suggest insect pollination, etc. (Li et al. 2005 and references). Engelhardia may be paraphyletic (Manos & Stone 2001).

Synonymy: Engelhardtiaceae Reveal & Doweld

2. Juglandoideae Eaton

Vessel elements with simple perforation plates alone; buds usu. with scales; staminate flowers: bracts 1-lobed, pollen usu. at least 26 µm [17-26 µm is the plesiomorphic condition] (with 4 or more pores); carpellate flowers: bracts unlobed, bracteoles usually lateral and adnate to the ovary; nuts with sclereids in shell, (endocarp with lacunae; outer part of fruit dehiscing [Carya]); (n = 15).

3-6/35. Temperate N. hemisphere, only 1 sp. in Europe, Central America and Andes (Map: see Meusel et al. 1965; Manchester 1987).

• Juglandaceae are evergreen or deciduous trees that may be recognised by the small, aromatic glands on the young parts of the plant; the compound, estipulate, usually spiral leaves the leaflets of which are often serrate; and the spicate inflorescences with single, axillary flowers. The endocarp of the drupaceous fruit often has complex intrusions.

The oldest fossils assignable to Juglandaceae may be from some 83-98 million years before present (Crepet et al. 2004 for references) or 78 million years before present (Manos et al. 2007, based on the age of Caryanthus). However, details of timing of diversification in the family are unclear, there being great variation of estimates in Juglandoideae in particular (Manos et al. 2007). Several genera are fossil in North America and especially Europe that are not found there now (Manchester 1987), and several extinct genera, some showing very interesting combinations of characters, are known from early Tertiary deposits in North America - clearly the family was very diverse there (Elliott et al. 2006). It seems that taxa with biotic means of dispersal evolved in the early Tertiary from taxa that were probably dispersed by wind (Tiffney 1986).

Triads of flowers are found as abnormalities (Manning 1940). Perfect flowers are known from Platycarya (Li et al. 2005, for which see floral development). Genera with opposite leaves (Alfaroa, Oreomunnea) have spiral leaves in seedlings. The stigma may be commissural or not and the orientation of the carpels varies (Manos & Stone 2001 for a summary). Pororate pollen in Juglandaceae is unlike that in other Fagales (Feuer 1991).

For chemistry, see Hegnauer (1966, 1989), for general information, see Stone (1993), for fertilisation, Luza and Polito (1991 and references), for relationships in the family, Gunter et al. (1994), for the fossil record, which is particularly well-known, Manchester (1991 and references). Manos and Stone (2001) provide a phylogeny and revised classification of the family; adjustments to current generic limits are needed.

Synonymy: Platycaryaceae Nakai ex Doweld

RHOIPTELEACEAE Handel-Mazzetti, nom. cons.   Back to Fagales

Chemistry?; cork?; sieve tube protein bodies?; buds lacking scales; leaves two-ranked, stipules asymmetrically caudate; inflorescence branched, flowers in triads; P 4, A 6, pollen 3-colporate, colpi short, G [2], ovule campylotropous, bitegmic, micropyle ?, fertilisation unknown, stigmas flattened, commissural, recurved; fruit a samaroid nut, P persistent; testa?.

1[list]/1: Rhoiptelea chiliantha. China, northern Vietnam, but fossil pollen from E. North America (Map: from Fu 1992).

• Rhoipteleaceae may be recognised by their stipulate and odd-pinnately compound leaves with serrate leaflets, indumentum of peltate scales, and branched, pendulous inflorescences with flowers in triads, the central flower apparently being perfect and having a superior ovary.

The ovary is presumably secondarily superior.

For chemistry, see Hegnauer (1990), for the breeding system, Sun et al. (2006), and for general information, see Wu and Kubitzki (1993).

Casuarinaceae [Ticodendraceae + Betulaceae]: dihydroflavonols +[?]; stigmas elongate; fertilization chalazogamous.

Sogo and Tobe (2008) suggest that the chalazogamous fertlization that occurs in all families of this clade is similar down to the details of where the pollen tube growth is temporarily delayed.

CASUARINACEAE R. Brown, nom. cons.   Back to Fagales

Roots with N-fixing Frankia, rootlets clustered, of limited growth [Proteoid roots]; flavonols, biflavonoids +, flavones, myricetin 0; nodes 1:1; stomata usu. tetracytic [hidden], transversely oriented [?sampling]; leaves 4-16-whorled, scale-like, margins entire, stipules 0; plant monoecious or dioecious, inflorescence capitate-spicate, one flower/bract, bracts and bracteoles ± well-developed; staminate flowers: P ["inner bracteoles"] 2, median, A 1, filaments incurved in bud, anthers ± longer than connective, pollen granules 0, pollen tube branched, pistillode 0; carpellate flowers: bracteoles large, P 0, G median, naked, only abaxial fertile, ovules straight [atropous], bitegmic, micropyle endostomal, archesporium multicellular, embryo sac with chalazal caecum, nucellar tracheids +; fruit a samara, freed as the much accrescent bracteoles separate; seed coat adnate to pericarp, testa vascularised?; endosperm 0; n = 8[Gymnostoma]-14.

4[list]/95. South East Asia and Malesia to the S.W. Pacific, esp. Australia (Map: from Coetzee & Muller 1984; George 1989). [Photo - Collection.]

• Casuarinaceae are easily recognised, looking as they do rather like a conifer. The minute leaves are whorled, and the carpellate inflorescence forms a small cone. The bracteoles that gape widely at maturity to release the samara fruits are very distinctive.

Casuarinaceae fossils are known from Tertiary deposits in South Africa and Argentina (Coetzee & Muller 1984); material from the Eocene of Patagonia has been identified as Gymnostoma (Zamaloa et al. 2006). Nitrogen fixing is known from the family, and Casuarina plays an important role in agriculture in parts of montane New Guinea, both in providing firewood and in fixing nitrogen.

Do flavananols occur in this family? The texture of what some have called the outer and inner bracteoles is very different; the latter is called the perianth above. The starch grains are distinctive (Czaja 1978). The ovules are described as being ascending by Takhtajan (1997).

Although the monophyly of Causarina has never been in doubt, it has been split into four genera, themselves probably monophyletic; Gymnostoma is sister to the rest of the family and has many plesiomorphous features. Both carpels are fertile (although this is likely to be an apomorphy, given the situation in the rest of the order), with 2 ovules/carpel, it stem stomata are not hidden, and perhaps n = 8.

See Hegnauer (1964, 1989: chemistry), Rogers (1982a), Johnson and Wilson (1993) and Sogo et al. (2001) for further information; Steane et al. (2003) for a phylogeny of the family.

Ticodendraceae + Betulaceae: sclereid nests with rhomboidal crystals in bark; mucilage cells +; leaves two-ranked.

TICODENDRACEAE Gomez-Laurito & L. D. Gomez P.   Back to Fagales

Bud scales 0?; hairs T-shaped, unicellular, not glandular; stipules encircling the stem; plant (polygamo-)dioecious; staminate flowers: P 0, A 8-10+; carpellate flowers: single, ?P minute, connate, G with divided loculi, ovules epitropous, hemitropous, integument 20-30 cells across; fruit drupaceous; exotestal cells initially radially elongated, all cells ± thick-walled and tanniniferous; endosperm development?; n = 13.

1[list]/1: Ticodendron incognitum. Central America (Map: from Hammel & Burger 1991). For checklist and bibliography, see Govaerts and Frodin (1998). [Photo - Fruit]

• Ticodendraceae are wind-pollinated trees that may be recognised by their doubly-serrate leaves that have stipules encircling the stem and carpellate flowers with two, long stigmas.

Fruits assignable to Ticodendron have been found in Eocene deposits from Oregon and in the London Clay (Manchester & Renner 2005).

The nodes are trilacunar, judging from the condition in the outer cortex. Almost all the leaf teeth are vascularised directly by secondary veins, unlike Betulaceae. The bracteoles of the carpellate flowers have groups of vascularised scales in their axils, suggesting that the carpellate inflorescence has a fundamentally cymose construction.

For information, see Carlquist (1991: wood), Feuer (1991: pollen), Tobe (1991: floral morphology), Kubitzki (1993b: general), Sogo and Tobe (2008: fertlization) and Govaerts and Frodin (1998: bibliography).

BETULACEAE Gray, nom. cons.   Back to Fagales

Trees or shrubs; flavones +; stratified phloem +; sieve tube P-protein usu. 0; leaves usu. laterally or vertically conduplicate, colleters +; plant monoecious or dioecious, catkinate; P 0-6, staminate flowers: (filaments ± divided), anthers longer than connective, pollen starchy, tube branched, G 0; carpellate flower: A 0, G [(3)], transverse (median), septae incomplete, (1-4 ovules/carpel), (short style +); n = 8, 11, 14; horizontal transfer of rps11 gene.

6[list]/145 - 2 groups below. North Temperate, to Andes and Sumatra (Map: from Meusel et al. 1965; Hultén 1971). For checklist and bibliography, see Govaerts and Frodin (1998: split into Corylaceae and Betulaceae). [Photo - Flower]

1. Betuloideae Arnott

No spirally-thickened vessel elements; peltate glandular hairs +; (leaves spiral Alnus); carpellate flowers: P 0; infructescence with woody or scaly bracts, separate fron small, ± flattened and samaroid nut.

2/95: Betula (60). N. hemisphere, to South America; montane in tropics.

The two genera are Alnus (N-fixing; prophyll adaxial) and Betula (3 carpellate flowers/bract).

2. Coryloideae J. D. Hooker

Spirally-thickened vessel elements, tracheids +; cymule with <3 flowers; staminate flowers: P 0, A hairy; carpellate flowers: P +, (embryo sac with chalazal caecum); infructescence with leafy bracteoles [from one or two orders of branching] remaining associated with the fruit; nuts large, not or little flattened.

4/50. N. Temperate, South East Asia, Central America.

The monophyly of Ostrya and Carpinus is unclear, as are many of the basic characters of the clade (cf. Yoo & Wen 2002). Staminate flowers in Coryloideae are sometimes reported as being single (e.g. Mabberley 1997), however, as Abbe (1935) noted, there are usually three; the flower of Ostrya, with some 15 pairs of half stamens, is pseudanthial in origin, being derived from three flowers (Abbe 1935, 1974; Macdonald in Sattler 1973: see also Nothofagaceae). In staminate flowers of Corylus the perianth is reduced to a ridge.

Synonymy: Carpinaceae Vest, Corylaceae Mirbel

• Betulaceae are usually deciduous trees that may be recognised by their stipulate, doubly serrate leaves, catkinate inflorescences (both staminate and carpellate), and fruits are that are either small and flattened or associated with large, leafy bract-like structures.

The oldest fossils assignable to the family are from 94-83 million years before present (Crepet et al. 2004 and Forest et al. 2005 for references). Normanthus and Endressanthus, from the late Cretaceous of Portugal, may be close to the root of the Betulaceae clade (Friis et al. 2005); the former has has perfect flowers with five perianth members that alternate with the stamens, and the placentation is described as being parietal (Schönenberger et al. 2001b; Friis et al. 2003a).

In Corylus avellana in particular there may be three to five months between pollination and fertilisation, ovules starting to develop about half way through this period and the nuts being 7-10 mm across at the time of fertilization. If pollination does not occur, the stigma may remain receptive for up to three months (Germain 1994). The ovary is not always obviously inferior.

Although Li et al. (2004) suggested that Betuloideae were paraphyletic, with Alnus and Betula being successively sister to the rest of the family, Forest et al. (2005), analysing variation in ITS and the 5S spacer, recovered the two subfamilies as monophyletic. The monophyly of Ostrya and Carpinus is unclear, as are many of the basic characters of Coryloideae (cf. Yoo & Wen 2002, 2007).

The two subfamilies are sometimes recognised as families, as by Brummitt (1992).

See Horne (1914), Heller (1935), Abbe (1935: flowers, inflorescences), Hegnauer (1964, 1989: chemistry), Crane (1989), Kubitzki (1993b: general), Manchester and Chen (1998), Chen et al. (1999: phylogeny and evolution), and Forest et al. (2005: phylogeny and a critical study of dating) for more information.