EMBRYOPSIDA Pirani & Prado
Gametophyte dominant, independent, multicellular, not motile, initially ±globular; showing gravitropism; acquisition of phenylalanine lysase [PAL], microbial terpene synthase-like genes +, triterpenoids produced by CYP716 enzymes, phenylpropanoid metabolism [lignans +, flavonoids + (absorbtion of UV radiation)], xyloglucans in primary cell wall, side chains charged; plant poikilohydrous [protoplasm dessication tolerant], ectohydrous [free water outside plant physiologically important]; thalloid, leafy, with single-celled apical meristem, tissues little differentiated, rhizoids +, unicellular; chloroplasts several per cell, pyrenoids 0; glycolate metabolism in leaf peroxisomes [glyoxysomes]; centrioles/centrosomes in vegetative cells 0, microtubules with γ-tubulin along their lengths [?here], interphase microtubules form hoop-like system; metaphase spindle anastral, predictive preprophase band + [with microtubules and F-actin; where new cell wall will form], phragmoplast + [cell wall deposition centrifugal, from around the anaphase spindle], plasmodesmata +; antheridia and archegonia jacketed, surficial; blepharoplast +, centrioles develop de novo, bicentriole pair coaxial, separate at midpoint, centrioles rotate, associated with basal bodies of cilia, multilayered structure + [4 layers: L1, L4, tubules; L2, L3, short vertical lamellae] (0), spline + [tubules from L1 encircling spermatid], basal body 200-250 nm long, associated with amorphous electron-dense material, microtubules in basal end lacking symmetry, stellate array of filaments in transition zone extended, axonemal cap 0 [microtubules disorganized at apex of cilium]; male gametes [spermatozoids] with a left-handed coil, cilia 2, lateral; oogamy; sporophyte multicellular, cuticle +, plane of first cell division transverse [with respect to long axis of archegonium/embryo sac], sporangium and upper part of seta developing from epibasal cell [towards the archegonial neck, exoscopic], with at least transient apical cell [?level], initially surrounded by and dependent on gametophyte, placental transfer cells +, in both sporophyte and gametophyte, wall ingrowths develop early; suspensor/foot +, cells at foot tip somewhat haustorial; sporangium +, single, terminal, dehiscence longitudinal; meiosis sporic, monoplastidic, MTOC [MTOC = microtubule organizing centre] associated with plastid, sporocytes 4-lobed, cytokinesis simultaneous, preceding nuclear division, quadripolar microtubule system +; wall development both centripetal and centrifugal, 1000 spores/sporangium, sporopollenin in the spore wall laid down in association with trilamellar layers [white-line centred lamellae; tripartite lamellae]; nuclear genome size [1C] <1.4 pg, main telomere sequence motif TTTAGGG, LEAFY and KNOX1 and KNOX2 genes present, ethylene involved in cell elongation; chloroplast genome with close association between trnLUAA and trnFGAA genes [precursors for starch synthesis], tufA gene moved to nucleus; mitochondrial trnS(gcu) and trnN(guu) genes +.
Many of the bolded characters in the characterization above are apomorphies of subsets of streptophytes along the lineage leading to the embryophytes, not apomorphies of crown-group embryophytes per se.
All groups below are crown groups, nearly all are extant. Characters mentioned are those of the immediate common ancestor of the group,  contains explanatory material, () features common in clade, exact status unclear.
Abscisic acid, L- and D-methionine distinguished metabolically; pro- and metaphase spindles acentric; class 1 KNOX genes expressed in sporangium alone; sporangium wall 4≤ cells across [≡ eusporangium], tapetum +, secreting sporopollenin, which obscures outer white-line centred lamellae, columella +, developing from endothecial cells; stomata +, on sporangium, anomocytic, cell lineage that produces them with symmetric divisions [perigenous]; underlying similarities in the development of conducting tissue and of rhizoids/root hairs; spores trilete; shoot meristem patterning gene families expressed; MIKC, MI*K*C* genes, post-transcriptional editing of chloroplast genes; gain of three group II mitochondrial introns, mitochondrial trnS(gcu) and trnN(guu) genes 0.
[Anthocerophyta + Polysporangiophyta]: gametophyte leafless; archegonia embedded/sunken [only neck protruding]; sporophyte long-lived, chlorophyllous; cell walls with xylans.
Sporophyte well developed, branched, branching apical, dichotomous, potentially indeterminate; hydroids +; stomata on stem; sporangia several, terminal; spore walls not multilamellate [?here].
Vascular tissue + [tracheids, walls with bars of secondary thickening]; stomata involved in gas exchange.
EXTANT TRACHEOPHYTA / VASCULAR PLANTS
Sporophyte with photosynthetic red light response, stomata open in response to blue light; plant homoiohydrous [water content of protoplasm relatively stable]; control of leaf hydration passive; plant endohydrous [physiologically important free water inside plant]; sporophyte with polar auxin transport, PIN [auxin efflux facilitator] involved; (condensed or nonhydrolyzable tannins/proanthocyanidins +); xyloglucans with side chains uncharged [?level], in secondary walls of vascular and mechanical tissue; lignins +; stem apex multicellular, with cytohistochemical zonation, plasmodesmata formation based on cell lineage; vascular development acropetal, tracheids +, in both protoxylem and metaxylem, G- and S-types; sieve cells + [nucleus degenerating]; endodermis +; leaves/sporophylls spirally arranged, blades with mean venation density ca 1.8 mm/mm2 [to 5 mm/mm2], all epidermal cells with chloroplasts; sporangia adaxial, columella 0; tapetum glandular; ?position of transfer cells; MTOCs not associated with plastids, basal body 350-550 nm long, stellate array in transition region initially joining microtubule triplets; suspensor +, shoot apex developing away from micropyle/archegonial neck [from hypobasal cell, endoscopic], root lateral with respect to the longitudinal axis of the embryo [plant homorhizic].[MONILOPHYTA + LIGNOPHYTA]
Sporophyte endomycorrhizal [with Glomeromycota]; growth ± monopodial, branching spiral; roots +, endogenous, positively geotropic, root hairs and root cap +, protoxylem exarch, lateral roots +, endogenous; G-type tracheids +, with scalariform-bordered pits; leaves with apical/marginal growth, venation development basipetal, growth determinate; sporangium dehiscence by a single longitudinal slit; cells polyplastidic, MTOCs diffuse, perinuclear, migratory; blepharoplasts +, paired, with electron-dense material, centrioles on periphery, male gametes multiciliate; chloroplast long single copy ca 30kb inversion [from psbM to ycf2]; mitochondrion with loss of 4 genes, absence of numerous group II introns; LITTLE ZIPPER proteins.
Sporophyte woody; stem branching lateral, meristems axillary; lateral root origin from the pericycle; cork cambium + [producing cork abaxially], vascular cambium bifacial [producing phloem abaxially and xylem adaxially].
Plants heterosporous; megasporangium surrounded by cupule [i.e. = unitegmic ovule, cupule = integument]; pollen lands on ovule; megaspore germination endosporic [female gametophyte initially retained on the plant].
EXTANT SEED PLANTS / SPERMATOPHYTA
Plant evergreen; nicotinic acid metabolised to trigonelline, (cyanogenesis via tyrosine pathway); microbial terpene synthase-like genes 0; primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignin chains started by monolignol dimerization [resinols common], particularly with guaiacyl and p-hydroxyphenyl [G + H] units [sinapyl units uncommon, no Maüle reaction]; root stele diarch to pentarch, xylem and phloem originating on alternating radii, cork cambium deep seated; stem apical meristem complex [with quiescent centre, etc.], plasmodesma density in SAM 1.6-6.2[mean]/μm2 [interface-specific plasmodesmatal network]; eustele +, protoxylem endarch, endodermis 0; wood homoxylous, tracheids and rays alone, tracheid/tracheid pits circular, bordered; mature sieve tube/cell lacking functioning nucleus, sieve tube plastids with starch grains; phloem fibres +; cork cambium superficial; leaf nodes 1:1, a single trace leaving the vascular sympodium; leaf vascular bundles amphicribral; guard cells the only epidermal cells with chloroplasts, stomatal pore with active opening in response to leaf hydration, control by abscisic acid, metabolic regulation of water use efficiency, etc.; axillary buds +, exogenous; prophylls two, lateral; leaves with petiole and lamina, development basipetal, lamina simple; sporangia borne on sporophylls; spores not dormant; microsporophylls aggregated in indeterminate cones/strobili; grains monosulcate, aperture in ana- position [distal], primexine + [involved in exine pattern formation with deposition of sporopollenin from tapetum there], exine and intine homogeneous, exine alveolar/honeycomb; ovules with parietal tissue [= crassinucellate], megaspore tetrad linear, functional megaspore single, chalazal, sporopollenin 0; gametophyte ± wholly dependent on sporophyte, development initially endosporic [apical cell 0, rhizoids 0, etc.]; male gametophyte with tube developing from distal end of grain, male gametes two, developing after pollination, with cell walls; female gametophyte initially syncytial, walls then surrounding individual nuclei; embryo cellular ab initio, suspensor short-minute, embryonic axis straight [shoot and root at opposite ends; plant allorhizic], cotyledons 2; embryo ± dormant; chloroplast ycf2 gene in inverted repeat, trans splicing of five mitochondrial group II introns, rpl6 gene absent; whole nuclear genome duplication [ζ - zeta - duplication], two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], 5.8S and 5S rDNA in separate clusters.
ANGIOSPERMAE / MAGNOLIOPHYTA
Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, apigenin and/or luteolin scattered, [cyanogenesis in ANA grade?], lignin also with syringyl units common [G + S lignin, positive Maüle reaction - syringyl:guaiacyl ratio more than 2-2.5:1], hemicelluloses as xyloglucans; root cap meristem closed (open); pith relatively inconspicuous, lateral roots initiated immediately to the side of [when diarch] or opposite xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0, hypodermis suberised and with Casparian strip [= exodermis]; shoot apex with tunica-corpus construction, tunica 2-layered; 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, not occluding pores of plate, companion cell and sieve tube from same mother cell; ?phloem loading/sugar transport; nodes 1:?; dark reversal Pfr → Pr; protoplasm dessication tolerant [plant poikilohydric]; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule, reduction in stomatal conductance with increasing CO2 concentration; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, overall growth ± diffuse, secondary veins pinnate, fine venation hierarchical-reticulate, (1.7-)4.1(-5.7) mm/mm2, vein endings free; flowers perfect, pedicellate, ± haplomorphic, protogynous; parts free, numbers variable, development centripetal; P +, ?insertion, members each with a single trace, outer members not sharply differentiated from the others, not enclosing the floral bud; A many, filament not sharply distinguished from anther, stout, broad, with a single trace, anther introrse, tetrasporangiate, sporangia in two groups of two [dithecal], each theca dehiscing longitudinally by a common slit, ± embedded in the filament, walls with at least outer secondary parietal cells dividing, endothecium +, cells elongated at right angles to long axis of anther; tapetal cells binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellate, endexine lamellate only in the apertural regions, thin, compact, intine in apertural areas thick, pollenkitt +; nectary 0; carpels present, superior, free, several, ascidiate [postgenital occlusion by secretion], stylulus at most short [shorter than ovary], hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, carinal, dry; suprastylar extragynoecial compitum +; 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, nucellar cap?; megasporocyte single, hypodermal, functional megaspore lacking cuticle; female gametophyte lacking chlorophyll, not photosynthesising, four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; ovule not increasing in size between pollination and fertilization; pollen grains land on stigma, bicellular at dispersal, mature male gametophyte tricellular, germinating in less than 3 hours, pollen tube elongated, unbranched, growing towards the ovule, between cells, growth rate (20-)80-20,000 µm/hour, apex of pectins, wall with callose, lumen with callose plugs, penetration of ovules via micropyle [porogamous], whole process takes ca 18 hours, distance to first ovule 1.1-2.1 mm; male gametes lacking cell walls, ciliae 0, siphonogamy; double fertilization +, ovules aborting unless fertilized; P deciduous in fruit; mature seed much larger than fertilized ovule, small [<5 mm long], dry [no sarcotesta], exotestal; endosperm +, cellular, development heteropolar [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 short [<¼ length of seed]; plastid and mitochondrial transmission maternal; Arabidopsis-type telomeres [(TTTAGGG)n]; nuclear genome size [1C] <1.4 pg [mean 1C = 18.1 pg, 1 pg = 109 base pairs], whole nuclear genome duplication [ε/epsilon event]; 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, palaeo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]]; chloroplast chlB, -L, -N, trnP-GGG genes 0.
[NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]]: wood fibres +; axial parenchyma diffuse or diffuse-in-aggregates; pollen monosulcate [anasulcate], tectum reticulate-perforate [here?]; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.
[AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: phloem loading passive, via symplast, plasmodesmata numerous; vessel elements with scalariform perforation plates in primary xylem; essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood + [reaction wood: with gelatinous fibres, G-fibres, on adaxial side of branch/stem junction]; tectum reticulate; anther wall with outer secondary parietal cell layer dividing; nucellar cap + [character lost where in eudicots?]; 12BP [4 amino acids] deletion in P1 gene.
[[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]] / MESANGIOSPERMAE: benzylisoquinoline alkaloids +; sesquiterpene synthase subfamily a [TPS-a] [?level], polyacetate derived anthraquinones + [?level]; outer epidermal walls of root elongation zone with cellulose fibrils oriented transverse to root axis; P more or less whorled, 3-merous [?here]; pollen tube growth intra-gynoecial; extragynoecial compitum 0; carpels plicate [?here]; embryo sac bipolar, 8 nucleate, antipodal cells persisting; endosperm triploid.
[CHLORANTHALES [[MAGNOLIALES + LAURALES] [CANELLALES + PIPERALES]]]: sesquiterpenes +; (microsporogenesis also simultaneous); seed endotestal.
[[MAGNOLIALES + LAURALES] [CANELLALES + PIPERALES]] / MAGNOLIIDS / MAGNOLIANAE Takhtajan: (neolignans +); root cap meristem open; vessels solitary and in radial multiples, (with simple perforation plates in primary xylem); (sieve tube plastids with polygonal protein crystals); lamina margins entire; A many, spiral [possible position here], extrorse; ovules with hypostase, nucellar cap +, raphal bundle branches at the chalaza; antipodal cells soon die. Back to Main Tree
4 orders, 20 families, 9900 species.
Age. Crown-group magnoliids diverged 134.5-125.7 m.y.a. (Moore et al. 2007), while Bell et al. (2010: note topology) suggested ages of (138-)122(-108) or (130-)125(-121) m.y. depending on the method used. Magallón and Castillo (2009) variously estimated crown group divergence at ca 201.7-198.2 and 128-127.7 m.y.a., while ca 149 m.y. is the estimate in Foster et al. (2016a, q.v. for details). Other estimates range from (181-)155(-136) m.y. old (with eudicot calibration) to (198-)163(-138) m.y. (without: Smith et al. 2010), to around 133.1 m.y. (Naumann et al. 2013), (144-)116(-89) m.y. (N. Zhang et al. 2012), (152.7-)117.3(-39.1) m.y. (Xue et al. 2012), around 146 m.y. (Tank et al. 2015: Table S1), or (155-)149, 137(-131) m.y. (Wikstöm et al. 2001). Magallón et al. (2013) suggested an age of around (167.2-)147.7-142.6(-128.5) m.y., Z. Wu et al. (2014) an age of about 186 m.y., Zanne et al. (2014) an age of ca 147 m.y., Magallón et al. (2015) an age of ca 132.4 m.y., while (180-)173, 131(-34) and (178.8-)174.6, 127.1(-126.8) m.y. are the ranges of ages in Zeng et al. (2014) and Massoni et al. (2015a) respectively.
An earlier fossil-based estimate for both stem and crown divergence is ca 98 m.y. (Crepet et al. 2004: magnoliids sister to monocots). For summaries of the fossil history of the group, especially prominent in the Mid Cretaceous and later, see Friis et al. (1997, 2006, 2011).
Evolution: Divergence & Distribution. Lesqueria, about 101 m.y.o., may belong around the magnoliids; it has similar fruits (Crane & Dilcher 1984), although the carpels are in some ways similar to those of Austrobaileya. The fruits of Protomonimia, in Turonian deposits from Japan ca 91 m.y.o., have several carpels borne in spirals on a concave axis; there is a stigmatic crest. The young seeds have a thick testa, the exotesta being palisade and with sinuous anticlinal cell walls (Nishida & Nishida 1988); they may belong to a taxon somewhere near Magnoliaceae, although i.a. the shape of the receptacle is very different (see also Laurales). For more discussion/fossils, see Friis et al. (2011) and Doyle (2014b).
For details of diversification within the whole clade, see Massoni et al. (2015a), the five main shifts, two up and three down, are mentioned under Magnoliales, Laurales and Piperales), although what might have caused these shifts is unclear. Also, our understanding of relationships within Lauraceae in particular is too poor to know what might be going on inside that family.
Ecology & Physiology. This clade has distinctively large leaves (Cornwell et al. 2014); magnoliids are generally plants of well watered, warm, and equable conditions. Carlucci et al. (2016) suggest that phylogenetic overdispersion in western Aamazonian tree communities near the Andes was partly because magnoliids with conserved habitat preferences - they though these were upland, shady and wet habittas (see also Feild & Arens 2007) - grew there, along with monocots and recently-diversifying eudicots. Of course Myristicaceae and many Annonaceae are plants of lowland rainforests.
Although may extant magnoliids are large trees, their litter decomposability and associated nutrient turnover tends to be at the slow end of the spectrum, Piperaceae being a notable exception (G. Liu et al. 2014).
Plant-Animal Interactions. Herbivory in magnoliids is relatively high (Turcotte et al. 2014: see caveats, Chloranthaceae not included). Caterpillars of Papilionidae-Papilioninae butterflies are notably common (almost 33% of the records) on members of this group; they are, however, not known on Myristicaceae, in Laurales they predominate on Lauraceae, and in Piperales two clades in particular are found on Aristolochiaceae (see Scriber et al. 1995 for references; Zakharov et al. 2004; Simonsen et al. 2011; Condamine et al. 2011). They are also commonly found on Rutaceae, which have similar alkaloids.
Chemistry, Morphology, etc. Hegnauer (1990) discussed the chemistry of the Polycarpicae, which in addition to this clade also includes Austrobaileyales and Ranunculales; similar isoflavonoids are found in Magnoliaceae, Lauraceae and Chloranthaceae.
For a convenient summary of a number of features of wood anatomy, see Herendeen et al. (1999b). Magnolioid roots are scattered through the clade, being recorded from a number of woody members of Laurales and Magnoliales. These roots are stout, often ³3 mm across, lack root hairs (?always), and are endomycorrhizal - associated conditions (see Baylis 1975; St John 1980). Taxa with broadly lobed leaf blades are scattered throughout this clade (but not in the small Canellales). See Erbar (1983, inc. Illicium) for carpel morphology and Ronse Decraene and Smets (1992b) for androecial morphology.
Phylogeny. The sister group relationship of Piperales with Canellales in particular is at first sight unexpected, but the magnoliid clade as a whole and the relationships within the group are turning out to be quite robust (Massoni et al. 2014: good generic sampling, 12 markers from three compartments). There was not much morphological support for this grouping (Doyle & Endress 2000), features like tectum structure, etc., showing considerable variation (J. A. Doyle 2005), and Piperales in particular tended to link with other groups (see the discussion at the mesangiosperm node for relationships of the magnoliids). However, molecular support for the clade is usually stronger in more recent studies (e.g. Qiu et al. 1999, 2000, 2005: support levels depend on the analysis, the node sometimes collapses], 2006b, 2010; Zanis et al. 2002; Jansen et al. 2006b; Zhengqiu et al. 2006; Cai et al. 2006; Müller et al. 2006: support for [Canellales + Piperales] poor; Jansen et al. 2007: little maximum parsimony support; Moore et al. 2007: group not evident in all analyses; Soltis et al. 2007a; Soltis et al. 2011; Foster et al. 2016a: q.v. for details, support rather poor). Support includes the possession of unique indels (Löhne & Borsch 2005). Soltis et al. (2007a) found weak support for a grouping [Magnoliales + Canellales]; relationships in Bell et al. (2010) are [Piperales [Laurales [Canellales + Magnoliales]]], although they, too, have little support.
Chloranthales, Ceratophyllales and monocots are the other clades immediately basal to the eudicots and all have somewhat uncertain positions.
[MAGNOLIALES + LAURALES]: cuticle waxes as annularly-ridged rodlets, palmitol the main wax; A whorled; pollen 1-2 nexine foliations, outer member massive, lamellate endexine; (supra-stylar extra-gynoecial compitum/pollen tube growth); carpel cross-zone initiated late; ovules 1(-2)/carpel, basal, erect, apotropous; fruitlets 1-seeded; palaeopolyploidization event.
Age. Magallón and Castillo (2009) suggest that the two clades diverged ca 198.2 and 127.7 m.y.a. - relaxed and constrained penalized likelihood datings, while the age in Foster et al. (2016a, q.v. for details) is around 138 m.y., that in Magallón et al. (2013) ca 137.2 m.y. and in Naumann et al. (2013) ca 126.4 m.y. ago, similar to the ca 127.7 m.y. suggested by Magallón et al. (2015). Xue et al. (2012) estimated an age of only 104.5 m.y., the lowest estimate so far, ca 126.9 m.y. is the estimate in Tank et al. (2015: Table S1), (176.8-)171.9, 124.3(-121.3) m.y.a. is the spread of ages in Massoni et al. (2015a).
Evolution: Divergence & Distribution. Cecilanthus, from early Cenomanian Maryland ca 100 m.y.a. or slightly younger, has a floral formula of * P many; A many; G many, with a well-developed receptacle and probably one ovule/carpel, that while perhaps Magnolialean might be assignable to Laurales, Nymphaeales, etc. (Herendeen et al. 2016).Both Laurales and Magnoliales have relatively high diversification rates, and extinction rates may have decreased in Laurales (Massoni et al. 2015a). For an increase in net diversification that can possibly be linked with a genome duplication that is associated with this node (Tank et al. 2015), see Lauraceae.
Ecology & Physiology. Members of this clade have notably thick rootlets, and this may be connected with more extensive ectomycorrhizal associations (Kong et al. 2014 and references; B. Liu et al. 2015). However, little is known about root thickness overall and its significance.
A major increase in seed mass, and to a lesser extent an increase in plant height and in leaf mass per area (SLA) can be pinned to this node (Cornelissen et al. (2014; for seed size, see also Moles et al. 2005a; Sims 2012).
Genes & Genomes. Cui et al. (2006) suggested that there had been a palaeopolyploidization event at this node (see also Soltis & Soltis 1990).
Chemistry, Morphology, etc. There is considerable variation as to how the androecium is initiated; it would not take much for "flowers with inner staminodes" to be an apomorphy at this level. For the supra-stylar compitum, see Wang et al. (2011). Lauraceae, Degeneriaceae and Magnoliaceae, at least, develop a massive, multiseriate suspensor during embryogenesis (Wardlaw 1955).
MAGNOLIALES Bromhead Main Tree.
(Si02 accumulation +); vessels in multiples; secondary phloem stratified; pith septate [with sclerenchymatous diaphragms]; nodes 3:3; petiole vasculature an arc with an adaxial plate; branching from the current innovation; leaves two-ranked, lamina vernation conduplicate; "bract" sheathing; P whorled; G occluded by fusion and secretion; ovule with outer integument 5-10 cells across, obturator +; seeds medium-sized, testa vascularized, multiplicative; endosperm ?type, ruminate, ruminations irregular. - 6 families, 154 genera, 2,829 species.
Age. Magallón and Castillo (2009) suggest possible ages for the crown group of around 171.5 and 116.6 m.y., Bell et al. (2010) ages of (96-)76, 69(-50) m.y.; other ages are (119-)113, 108(-102) m.y. (Wikstöm et al. 2001) and (164.1-)156.8, 117.3(-116) m.y.a. (Massoni et al. 2015a).
Note: Boldface denotes possible apomorphies, (....) denotes a feature common in the clade, exact status uncertain, [....] includes explanatory material. Note that the particular node to which many characters, particularly the more cryptic ones, should be assigned is unclear. This is partly because homoplasy is very common, in addition, basic information for all too many characters is very incomplete, frequently coming from taxa well embedded in the clade of interest and so making the position of any putative apomorphy uncertain. Then there are the not-so-trivial issues of how character states are delimited and ancestral states are reconstructed (see above).
Evolution: Divergence & Distribution. For Cecilanthus, from early Cenomanian Maryland ca 100 m.y.a., see Herendeen et al. (2016) and above).
There is extensive discussion on character evolution in Sauquet et al. (2003), and some of the character hierarchy here is based on this paper. However, where characters like extrorse/introrse anther dehiscence and ruminate/non-ruminate testa are placed on the tree depends on how the characters are optimised, or even defined (e.g. ruminate endosperm). There is also some conflict with the positions of characters as they are optimised on a more extensive tree for basal angiosperms, although less detailed for Magnoliales (c.f. Ronse De Craene et al. 2003, also Judd et al. 2003). Doyle and Endress (2000) and Soltis et al. (2005) suggest additional characters for the clade, including reduced fibre pit borders, palisade parenchyma, foliar astrosclereids; Doyle (2009) and Doyle and le Thomas (2012, see also 1997) outline pollen evolution, and variation in the nature of the exine infractetcum is considerable. Characters may well need to be added to/moved in the apomorphy scheme for the order.
Ecology & Physiology. Magnoliaceae, along with Theaceae, Lauraceae and Fagaceae (Tang 2015), are a notably prominent component of the subtropical evergreen broad-leaved forests of East Asia.
Genes & Genomes. Morawetz (e.g. 1986b, 1988, see also Doyle & Le Thomas 1997) describe distinctive patterns of chromosome condensation in the order. See S. Kim et al. (2003, 2004, 2005a) for the AP3 and P1 genes, Myristicaceae were not sampled.
Chemistry, Morphology, etc. Intra- and interfamilial variation of morphological characters that are frequently used to reconstruct phylogenies is considerable, in particular, Furness et al. (2002) emphasize the variability of microsporogenesis in the order.
The "bracts" with sheathing bases that have been reported for a number of Magnoliales (Endress & Armstrong 2011: condition in Degeneriaceae?), are perhaps a little unexpected since the leaf bases in the clade tend to be quite narrow - except for the stipulate Magnoliaceae. Deroin (2010) noted a tendency for the vasculature of the perianth and/or androecium in some Annonaceae and Magnoliaceae to be pentamerous.
For additional information, see Taylor and Hickey (1995: general), Benzing (1967) and Sugiyama (1976a, b, 1979), all nodal anatomy, considerable variation in cotyledonary node, Metcalfe (1987: general anatomy), Hiepko (1964b: perianth vasculature), Endress (1977b, 1986a, 1994a: floral morphology), Erbar and Leins (1983: floral development), Ronse Decraene and Smets (1996a: androecium), van Heel (1981, 1983: carpel development), and Kimoto and Tobe (2001: embryology).
Phylogeny. Molecular data suggested that Myristicaceae are sister to the rest of the order, but support was only moderate (D. Soltis et al. 2000); the addition of morphological data strengthened that position, and also placed Magnoliaceae as sister to the remaining taxa (Doyle & Endress 2000), although the latter position had only moderate support (c.f. P. Soltis et al. 2000; see also Sauquet et al. 2001). The family pairs [Annonaceae + Eupomatiaceae] and [Degeneriaceae + Himantandraceae] are both well supported (D. Soltis et al. 2000; P. Soltis et al. 2000; Doyle & Endress 2000). Other studies confirm these general relationships (Sauquet et al. 2003; Müller et al. 2006; Z.-D. Chen et al. 2016), and they are followed here, however, the position of Magnoliaceae in particular remains unclear. Some genes seems to have particularly disconcerting effects, thus the 26S rDNA gene caused the association of Degeneriaceae with Myristicaceae, and this was not because of a mislabelled sequence (Massoni et al. 2014).
Hilu et al. (2003: matK analysis alone, ?sampling) found a somewhat different but poorly supported set of relationships, and Qiu et al. (2010: mitochondrial genes) also recovered a somewhat different topology, Degeneriaceae being sister to the rest of the order minus Myristicaceae, although again support was weak. Soltis et al. (2011) found that Magnoliaceae were sister to the rest of the order, the clade [Degeneriaceae + Myristicaceae] had good support although otherwise support was weak; this unexpected topology was ascribed to signal from rDNA sequences. Finally, Morton (2011: nuclear gene Xdh) found a set of relationships [Himantandraceae [Myristicaceae [Degeneriaceae [the rest]]]] while relationships in Magallón et al. (2015) are [[Magnoliaceae [Degeneriaceae + Myristicaceae]] the rest].
Includes Annonaceae, Degeneriaceae, Eupomatiaceae, Himantandraceae, Magnoliaceae, Myristicaceae.
Synonymy: Annonales Berchtold & Presl, Degeneriales C. Y Wu et al., Eupomatiales Reveal, Himantandrales Doweld & Shevyryova, Myristicales Berchtold & Presl - Magnoliineae, Myristicineae Chatrou - Annonanae Doweld, Magnolianae Takhtajan - Magnoliidae Takhtajan - Magnolipsida Brongniart - Magnoliid I group (Nandi et al. 1998).
MYRISTICACEAE R. Brown Back to Magnoliales
Tree, branches plagiotropic, pseudowhorled; exudate +, red; isoflavonoids, flavonoids diverse [flavones +], polyketide [acetogenins], (tryptamine) alkaloids +, isoquinoline alkaloids 0; cork also in outer cortex; primary stem ± with continuous cylinder; vessel elements with simple or scalariform(-reticulate) perforations; tannin-containing tubes in the xylem; sieve tubes with non-dispersive protein bodies, (plastids with protein crystalloids and starch); petiole bundles bicollateral; (branched) sclereids or fibres +; (acicular) crystals +; hairs branched, arbuscular to stellate (T-shaped); cuticle waxes as platelets; (leaves spiral), (lamina lobed - some Knema); plants dioecious; flowers small (<1 cm across), polysymmetric, receptacle small; P (2-)3(-5), uniseriate, connate; staminate flowers: A whorled (spiral), 2-40, connate (partly - Mauloutchia), (anthers locellate); (pollen inaperturate, ulceroid, spiraperturate), pollen aperture membrane sculpted, (exine infratectum ± granular); pistillode 0, central column +, receptacular or not; carpellate flowers: staminodes 0; G 1; (stylulus ± long), stigma 2-lobed to peltate; compitum necessarily 0; ovule 1/carpel, subbasal, inner integument (3-)7-10 cells across; fruit a follicle, dehiscing abaxially as well, (indehiscent); seed large [³1 cm across], pachychalazal, aril +, micropylar-funicular, vascularized, (aril small); exotesta thick-walled, endotesta palisade, lignified, crystalliferous, tegmen multiplicative or not, exotegmen with fibres or sclerotic or tracheidal cells, chalaza massive, with a lignified counter-palisade; endosperm nuclear, with (starch and) oil; embryo with hypocotyl not developed; n = 20, 22, 25, 26; germination epigeal, phanerocotylar, or hypogeal.
20[list]/475: Myristica (175), Horsfieldia (100), Knema (95), Virola (60). Pantropical, few mainland Africa (map: from de Wilde 2000 [Indo-Malesia]; Heywood 2007; Trop. Afr. Fl. Pl. Ecol. Distr. 1. 2003).[Photo - Carpellate flower, Fruit].
Age. Crown-group Myristicaceae are estimated to be a mere 21-15 m.y.o. (J. A. Doyle et al. 2004) or (51.5-)32.6, 13.8(-10.2) m.y.o. (Massoni et al. 2015a).
The discovery of fossil seeds apparently of Myristicaceae from the Eocene (London Clay) does not bear on the crown-group age because they cannot be placed precisely on the tree of the family (J. A. Doyle et al. 2008a).
Floral formula: * P ; A [2-40]: * P ; G 1.
Evolution: Divergence & Distribution. Crown-group diversification in Myristicaceae, some 21-15 m.y.a., is very recent indeed given possible stem ages of the family that are over 100 m.y. more (see above), its distribution throughout the humid tropics, and its apparently low dispersability (J. A. Doyle et al. 2004). Sauquet et al. (2003) also found a long branch leading to crown Myristicaceae and little molecular divergence between its extant members, which also suggests recent diversification. In this respect Myristicaceae can be compared with Annonaceae, also pantropical but a little younger; there diversification may have begun mid-Cretaceous or slightly later (Doyle et al. 2004; Scharaschkin & Doyle 2005; esp. Couvreur et al. 2011a; Doyle et al. 2012). Furthermore, Buerki et al. (2013; see Sauquet et al. 2003, support for relationships hardly very strong) suggested that the closest relatives of the large-fruited Malagasy Haematodendron were to be found in the New World, long distance dispersal explaining the disjunction.
See Sauquet et al. (2003) and Chatrou (2003) for possible apomorphies.
Ecology & Physiology. Myristicaceae are disproportionally well represented (11 of the 57 species of the family recorded) of the 227 common trees (d.b.h. at least 10 cm) of the Amazonian forests (ter Steege et al. 2013).
Pollination Biology & Seed Dispersal. Pollination in the Indo-Malesian region, at least, is by small beetles (Corlett 2004; Gottsberger 2016 for a summary).
Seed dispersal is by primates and toucans in the New World and hornbills, pigeons and birds of paradise in the Old World; the aril may be quite thin but it is nutritious (McKey 1975; Fleming & Kress 2013).
Genes & Genomes. Isozyme duplication (in Myristica) suggests ancient polyploidy (Soltis & Soltis 1990). There are reports of holocentric chromosomes from Myristica fragrans (Escudero et al. 2016b and references).
Chemistry, Morphology, etc. There are free phloem strands in the centre of the midrib bundle. The wood rays are not notably broad.
Inflorescence morphology is a little confusing. Ronse de Craene (2010; see also Armstrong & Tucker 1986) shows a large, abaxial "bracteole" in addition to paired lateral prophyllar/bracteolar-like structures that may (staminate inflorescence) or may not subtend buds. The "bract" immediately below the staminate flower of Myristica fragrans has a very broad base.
The perianth lobes each have three traces (Siddiqui & Wilson 1976). The synandrium of Myristica has a sterile apex, probably axial (Armstrong & Tucker 1986), and judging from the vasculature, the unithecal anthers found in some species of Myristica represent half of a divided bithecal anther (Wilson & Maculans 1967; Armstrong & Tucker 1986); anthers in Knema are tetrasporangiate (Xu & Ronse de Craene 2010a). However, the androecial vasculature varies as does the nature of the central sterile column of the staminate flower (G.-F. Yang & Xu 2016). For the complex vascularisation of the carpel in Myristica, see Wilson and Maculans (1967), and for the vascularization of the ovule in Myristica fragrans, see Dickison (2000). A small structure developing between the two integuments is reported by Nair (1972). Corner (1976) commented on the complexity of the seed coat in Myristicaceae which is as elaborate as that of any other angiosperm. Not all taxa appear to have a multiplicative testa, and some have a multiplicative tegmen; the ruminations may develop best in the pachychalazal part of the seed.
For more information, see Kühn and Kubitzki (1993: general), de Wilde (2000: Malesian Myristicaceae), Hegnauer (1969, 1990: chemistry), Kerster and Baas (1981: anatomy), Cremers (1973) and Jiménez-Rojas et al. (2002), both growth patterns, Sauquet (2003: androecium), Sauquet and Le Thomas (2003: pollen), Mauritzon (1939a) and Endress (1973), both seeds, and Oginuma et al. (2012: chromosome numbers, a few South East Asian-Malesian taxa only known).
Phylogeny. Relationships within the family are unclear. The African and Madagascan taxa may form a clade, possibly sister to Compsoneura (but perhaps long branch attraction), overall, geography and relationships may be summarized as [[Asia + America] [Madagascar and Africa]]. Within Asian/Malesian Myristicaceae, Knema and Myristica may be sister taxa. Sauquet et al. (2001, 2003), Sauquet (2003) and Sauquet and Le Thomas (2003) suggest that the free stamens (in some species they are numerous and apparently spirally inserted) and small aril of Mauloutchia, apparently plesiomorphic features, are in fact more likely to be derived.
[Magnoliaceae [[Degeneriaceae + Himantandraceae] [Eupomatiaceae + Annonaceae]]]: primary stem with distinct bundles [eustele]; wood with broad rays; flowers solitary, large [>1.5 cm across]; P = K + C; A many, spiral [possible position here], filaments with three veins, anther thecae separate, embedded in the broad connective, connective prolonged [one position]; tectum imperforate; G spiral; ovule with funicular obturator; ³1 seeds/fruitlet; 10-aa deletion in PI-derived motif in AP3 gene.
Age. This node can be dated to 120-100 m.y.a. (Doyle et al. 2004), also (108-)101, 97(-90) m.y.a. (Wikström et al. 2001), (106-)102(-98) m.y.a. (Su & Saunders 2009), ca 114.8 m.y. (Naumann et al. 2013), or as recently as ca 71.1 m.y.a. (Magallón et al. 2013).
Chemistry, Morphology, etc. There is more than one kind of cortical vascular system here, and what parts of the flower are supplied by which system varies (Ronse De Craene et al. 2003, see also Deroin 1991, 1999a).
MAGNOLIACEAE Jussieu Back to Magnoliales
(Silicon concentration high), sesquiterpene lactones +; vessel elements with simple and scalariform perforation plates; wood fluorescing; (secondary phloem ± stratified, rays broad); nodes >6:>6; pith septate; resin cells +; hairs simple; lamina vernation laterally or vertically conduplicate (supervolute-curved), stipules +, sheathing stem, open opposite petiole; flowers terminal or axillary, ± polysymmetric; receptacle much elongated; K and C ± distinguishable, ± whorled; (endothecium biseriate), (filament vein single); tapetal cells multinucleate; pollen grains boat-shaped; G 1-many, fusion complete, but secretory canal +, stigma (terminal), dry, elongate (not); ovules(1-)2-12(-16)/carpel, micropyle exo/bistomal/zig-zag, inner integument 2-3(-4) cells across, parietal tissue 2-8 cells across; fruit dehiscing abaxially (circumscissile), or indehiscent, winged; sarcotesta +, towards inside /with crystals, endotesta lignified [fibres], (tegmen ± tanniniferous); endosperm not ruminate; n = 19.
2[list]/227: Magnolia (ca 225). The Americas (but not W. North America), and South East Asia to Malesia (map: from Good 1974; Lozana-Contreras 1994).[Photo - Collection.]
Age. Molecular estimates of the crown group age are (54-)36, 33(-17) m.y. (Bell et al. 2010: note topology), (86-)79, 70(-63) m.y. (Wikström et al. 2001) and (115.1-)94, 33.8(-5.7) m.y.o. (!!: Massoni et al. 2015a).
Archaeanthus, a Cenomanian fossil of some 96.5 m.y. in age from North America, may be assignable to Magnoliaceae (Dilcher & Crane 1984); it is placed sister to the family in the constrained morphological analysis of Doyle and Endress (2010; see also Friis et al. 2011; Massoni et al. 2015b: detailed discussion of its placement). It has follicular fruits that fall off the axis and each follicle has 10-18 winged seeds. Romanov and Dilcher (2013: ?outgroup) placed Archaeanthus, along with Liriodendroidea, known from its winged seeds, as sister to Liriodendron, which would call into question the accuracy of the molecular age estimates above.
1. Magnolia L.
(Deciduous); sieve tube plastids with polygonal protein crystalloids and starch - Magnolia; petiole also with medullary bundles; veinlet endings with dead enlarged cells with wall adjacent to tracheary element thickened [= tracheoidal element]; leaves also spiral, (lamina emarginate), (stipules not encircling stem); (plant dioecious); P 2, 3 + 3, or 3 + many, (outer 3 members small, K-like); anthers introrse/latrorse; (exine infratectum granular); nectar secretory by carpel epidermis; ovule lacks a funicular obturator(?); fruit dehiscent ad/abaxially [so fruit is not follicle sensu stricto], (circumscissile), (fleshy, indehiscent); sarcotesta +, scleroendotesta with crystals and lignified fibrils in the cells, pore marking passage of vascular bundle; endosperm copious, (nuclear - "Magnolia" septentrionalis).
1/225. The Americas (but not W. North America), and South East Asia to Malesia.
2. Liriodendron L.
Deciduous; wood vestured; petiole bundle strictly annular; leaves spiral, lobed, with palmate secondary veins; P 3 + 3; fruit a samara, seed 1; testa inconspicuous, sarcotesta 0, mesotesta more or less sclerotic; endosperm slight and not ruminate.
1/2. East Asia, east North America
Evolution: Divergence & Distribution. Magnoliaceae have a rich fossil record (Friis et al. 2011 for references). Liriodendron was widely distributed in the Northern Hemisphere in the early Caenozoic (Ferguson et al. 1997).
About three quarters of all Magnolia grow in China, and Liu et al. (2016) found substantial phylogenetic conservatism of many of the plant traits that they studied. For divergence ages of and within Magnolia, see Azuma et al. (2001) and Nie et al. (2008).
Pollination Biology. Beetles are common pollinators, but insects like flies and bees are other pollinators, and the flowers of species like Magnolia ovata, pollinated by dynastid scarab beetles, are thermogenic (Seymour 2001; Gottsberger et al. 2012; Gottsberger 2016: summary). Floral scents of the family have been extensively studied (Azuma et al. 1999; Gottsberger et al. 2012); for nectar secretion by the carpels, see Erbar (2014 and references).
Genes & Genomes. Both isozyme duplication and stomatal size increase over time suggest ancient polyploidy (Soltis & Soltis 1990; Masterson 1994).
Chemistry, Morphology, etc. Sclerenchymatous diaphragms in the pith of the stem are particularly conspicuous in the Michelia group of Magnolia. Terminal tracheids are commonly silicified, forming distinctive phytoliths (Piperno 2006) and veinlets often terminate in tracheoidal elements (see above) and a variety of other distinctive cell types (Tucker 1964).
Flowers of Magnolia that appear to be axillary terminate short shoots; growth in taxa with such flowers is monopodial, but otherwise it is sympodial (Praglowski 1974).
For floral development in some species of Magnolia and ABC gene expression, see Wróblewska et al. (2016). The endexine is lamellate and the columellae fused-granular (Xu & Kirchoff 2008). Nectar is secreted from the exposed surfaces of the carpels in some species of Magnolia. The micropyle is exostomal in the Michelia group of Magnolia. The seed of Magnolia may dangle from the open fruitlet attached by extended annular thickenings of the protoxylem vessels. There is a simple or tubular pore in the seed coat of Magnolia that marks the passage of the vascular bundle through the sclerotesta (Xu 2003). Friis and Pedersen (2011) discuss variation in the thickness of the crystal-bearing tissue in the testa.
For additional information, see Praglowski (1974) and Nooteboom (1993), both general, Hegnauer (1969, 1990: chemistry), Yoshizawa et al. (2000: ?absence of tension wood, but see Roussel & Clair 2015), Figlar (2000: branching patterns), Charlton (1994) and Liao and Xia (2007), phyllotaxis and vernation, F.-X. Xu (2006) and Xu and Rudall (2006), floral development, Praglowski (1974), Xu and Kirchoff (2008) and Gabarayeva and Grigorjeva (2012), all pollen morphology, Bouman (1977: ovules and seeds of Liriodendron), Yamada et al. (2003b: ovules), and Pan et al. (2003) and especially Fu et al. (2012 and references), embryology
Phylogeny. Magnolia s. str. is pretty wildly paraphyletic, and section Talauma is sister to the rest of Magnolia (Qiu et al. 1995; S. Kim et al. 2001a, b; Z.-D. Chen et al. 2016). Support along the backbone of the Magnolia phylogeny is poor, although there are 11 or more well-supported clades along it (Azuma et al. 2000, 2001, 2011; Nie et al. 2008; S. Kim & Suh 2013). See also Ueda et al. (2000) and Y.-L. Wang et al. (2006) for molecular phylogenies.
Classification. It seems best to recognize a broad Magnolia that encompasses the whole of the current Magnolieae; the family thus includes only two genera and tribes are superfluous (see Nooteboom 2000; Nooteboom in Xia et al. 2008; Kim & Suh 2013). However, Romanov and Dilcher (2013) need an order for the family, while Xia (2012) and Sima and Lu (2012) provide a reclassification of Magnolia in which it is divided into 16 genera placed in two tribes. For a checklist and bibliography (under some old generic names), see Frodin and Govaerts (1996).
Synonymy: Liriodendraceae F. Barkley
[[Degeneriaceae + Himantandraceae] [Eupomatiaceae + Annonaceae]]: flower haplomorphic; anthers valvate[H-dehiscence], inner staminodes +; pollen smooth, exine thin, exine infratectum ± granular; [0.2-1.3 µm across], nexine foliations?; style with differentiated transmission tissue; seed ruminations irregular [DELTRAN optimization], mesotesta fibrous.
Age. Ages around here are ca 92.5 m.y. (Tank et al. 2015: Table S1, S2, c.f. topology).
Endressinia brasiliana, from the Brazilian Crato formation of some 113 m.y.a., has i.a. distinctive glandular staminodia. It is placed sister to this clade by Doyle and Endress (2010; see also Massoni et al. 2015b), largely confirming the position suggested by Mohr and Bernardes-de-Oliviera (2004). However, Mohr et al. (2013) linked it with Schenkeriphyllum and put the two in a clade sister to Magnoliaceae (see also Doyle 2014b)...
Evolution: Divergence & Distribution. There may have been a slow-down in diversification at this node (Massoni et al. 2015a).
<Pollination Biology & Seed Dispersal. The staminodes in particular produce a secretion, not nectar, presumably involved in pollination (Erbar 2014; Gottsberger 2016).
Chemistry, Morphology, etc. Doyle (2007) noted that the venation here is often poorly differentiated and so of low rank (but c.f. many Annonaceae, albeit not "basal" members) - I have not placed this character on the tree.
Doyle (2009) noted that the pollen exine of Degenria, Galbulimima and Eupomatia was more or less homogeneous, although basically granular. For the inner staminodes that are often so conspicuous in the flowers, and their function in pollination - food for pollinators, attractants - see Endress (1984).
[Degeneriaceae + Himantandraceae]: flowers axillary; nexine foliations absent; outer integument with annular opening; x = 12.
Age. The age of this node is around (59-)42, 38(-22) m.y. (Bell et al. 2010), (80-)73, 63(-56) m.y. (Wikström et al. 2001), c.f. topology, or (146.2-)134.2, 59.9(-17.1) m.y. (Massoni et al. 2015a).
Evolution: Divergence & Distribution. Diversification rates in this clade show a notable slow-down (Massoni et al. 2015a).
DEGENERIACEAE I. W. Bailey & A. C. Smith Back to Magnoliales
Alkaloids 0; cork ?; vessel elements with scalariform perforation plates; sieve tube plastids with polygonal protein crystalloids and starch; nodes 5:5; petiole also with medullary bundles; secretory cells 0; cuticle waxes as platelets; leaves spiral; bracts?; K 3, C many, whorled; pollen boat-shaped; G 1, basally ascidiate, occluded by fusion only, stigmatic crest much elongated; compitum necessarily 0; ovules many/carpel, inner integument ca 3 cells across, funicle long; fruit a follicle; exotestal cells palisade, thin-walled, sarcomesotesta +, endotesta with crystals and lignified internal fibrils; suspensor massive, embryo with 3 (4) cotyledons.
1[list]/2. Fiji, Viti Levu (map: original!).
Chemistry, Morphology, etc. Some information is taken from Hegnauer (1973, 1990, as Winteraceae: chemistry) and Kubitzki (1993b: general).
HIMANTANDRACEAE Diels Back to Magnoliales
Polyketide alkaloids only; vessel elements with simple (and scalariform) perforations; sieve tubes with non-dispersive protein bodies; trichomes peltate; cuticle wax crystalloids 0; branching?; P or bract + bracteoles enclosing the flower in 2 series, caducous, or 2 connate + 4 connate; "C" 3-23 [= outer staminodes], inner staminodes +, with glands; pollen scabrate; G 6-30, (1) 2 pendulous ovules/carpel; suprastylar extragynoecial compitum +; fruit ± syncarpous, drupaceous, with several stones; seeds laterally flattened, ?ruminations; testa not multiplicative, endotesta aerenchymatous; endosperm development?; seedling?
1 (Galbulimima)[list]/2. The Celebes, New Guinea and N.E. Australia (map: from Hoogland 1972; Endress 1983). [Photo - Flower, Fruit, Buds, Habit]
Chemistry, Morphology, etc. For the testa, see Doweld and Shevyryova (1997); the ruminations are at best obscure. The perianth may be staminodial in origin; according to Johri et al. (1992) the outer integument is not vascularized. Some other information is taken from Hegnauer (1966, 1989: chemistry) and Endress (1993: general).
[Eupomatiaceae + Annonaceae]: sieve tube plastids also with polygonal protein crystalloids; rays 8-15-seriate; petiole bundles arcuate; trunk leaves spiral; prophyll single, adaxial; lamina vernation conduplicate; inflorescence +; nexine foliations undifferentiated; G many; fruit ± berry-like.
Age. Estimates of the time of divergence of these two families vary considerably: Around (69-)55, 50(-35) m.y. (Bell et al. 2010), ca 64.75 m.y. (Naumann et al. 2013), (97-)91, 82(-76) m.y. (Wikström et al. 2001), and (110.4-)106.3(-102.0) m.y. (Couvreur et al. 2011a: HPD estimates). Other suggested ages are (110.4-)101.7(-99.4) m.y. (Surveswaran et al. 2010: HPD estimates), (101.5-)98.0(-94.9) m.y. (Su & Saunders 2009), or somewhere between 84.7 and 62.6 m.y. (Erkens et al. 2009: a variety of estimates); see also the estimate of 109-100 m.y.a. in Pirie and Doyle (2012), ca 94.2 m.y. in Magallón et al. (2015), (148.4-)138.5, 102.5(-86) m.y. in Massoni et al. (2015a), and ca 81.2 m.y. in Tank et al. (2015: Table S1).
Evolution: Divergence & Distribution. Optimisation of prophyll position on the tree is uncertain. Adaxial prophylls are common in Annonaceae, including Anaxagorea, although some taxa have paired, lateral prophylls (Fries 1911).
EUPOMATIACEAE Orban, nom. cons. Back to Magnoliales
Also rhizomatous, with xylopodium or root tubers; pith not septate; vessel elements with scalariform perforation plates; secondary phloem stratification?; sieve tubes with non-dispersive protein bodies [check], plastids also with protein rods; nodes (5-)7(-11):(5-)7(-11); secretory cells +; (stomata anomocytic); inflorescence fasciculate; receptacle concave, calyptra +, thick, deciduous, with sclereids, phyllotaxis spiral; P 0; A introrse, staminodes 15+, petal-like, connate basally, with many glands; pollen with encircling equatorial sulcus; G ± connate, ascidiate, occluded by fusion only, placentation sublaminar, stigma flat, papillate, suprastylar extragynoecial compitum + [at least inner carpels]; ovules 2-11/carpel; fruit a "berry"; testa ?not vascularized, exotestal cells with thickened unlignified walls, endotesta unlignified, exotegmic cells cuboid, slightly lignified, endotegmic cells enlarged, crushed; n = 10; germination epigeal/phanerocotylar.
1[list]/3. New Guinea and E. Australia (map: from Hoogland 1972; Endress 1983). [Photos - Flower, Flower]
Evolution: Pollination Biology & Seed Dispersal. Pollination is by beetles which both mate and oviposit on the flowers (summarized by Gottsberger 2016).
Chemistry, Morphology, etc. The main axes are mixed, initially being orthotropic and bearing spirally-arranged leaves, later becoming more or less plagiotropic and with 2-ranked leaves. There are about three two-ranked bracts on the pedicel; the calyptra itself is often interpreted as being a modified, amplexicaul bract (e.g. Endress 2003b; esp. S. Kim et al. 2005b). There is no evidence of isozyme duplication (Soltis & Soltis 1990).
Some information is taken from Hegnauer (1966, 1989: chemistry), Endress (1983, 1993: general) and Rix and Endress (2007: an easy account).
ANNONACEAE Jussieu Back to Magnoliales
Vessel elements with simple perforation plates; parenchyma in bands joining rays; lateral traces leaving stele well before central trace; sieve tube plastids also with protein filaments; epidermal cells with single crystals [?level]; (inflorescence leaf-opposed); pedicels articulated [level?]; flowers 3-merous, polysymmetric, pistillate and staminate phase flowers not on same plant; P very thick, 3, ± calycine, valvate, + 3 + 3, ± corolline, open to valvate; A whorled, filaments with a single vein; G plicate; (suprastylar extragynoecial compitum); funicle short; monocarp abscission at the base; endotestal plug +, mesotesta with several layers of longitudinal and internally of transverse fibres, aerenchyma internal; vascular bundle in antiraphe.
129[list]/2,120 - four groups below. Largely tropical.
Age. Crown group diversification may have occurred (90.4-)89.5(-89) m.y.a. (Su & Saunders 2009: calibration on Futabanthus), 82-57 m.y.a. (J. A. Doyle et al. 2004), ca 84 m.y.a. (Scharaschkin & Doyle 2005; check), 98-89 m.y. (Pirie & Doyle 2012) or (126.7-)114.1, 85.3(-72.4) m.y. (Massoni et al. 2015a); see Couvreur et al. (2011a) for other estimates.
Futabanthus, based on fossil flowers from the late Cretaceous (Early Coniacian, ca 89 m.y.a.) of Japan, can perhaps be assigned to crown-group Annonaceae (Takahashi et al. 2008b; Friis et al. 2011). Indeed, Annonaceae seem to have been widely distributed by the end of the Cretaceous (Friis et al. 2011; Wheeler et al. 2017).
1. Anaxagoreoideae Chatrou, Pirie, Erkens & Couvreur
Ray cells with druses; uniseriate hairs terminate in a rounded cell, other hairs ± stellate; (petiole vascular tissue ± annular; with adaxial bicollateral plate; small arcuate bundles variously arranged); stomata allelocytic; trunk leaves 2-ranked; anther connective tongue-like, inner staminode secretions 0; orbicules +; G (3<), receptacular vascular system 0; ovules 2/carpel, stigma sessile; fruit an explosively dehiscent follicle; seed asymmetric; endotesta aerenchymatous, tegmen alone involved in ruminations, with oil globules; n = 8.
1/21. Tropical America, Sri Lanka to West Malesia, also Halamahera and Ceram (map: from Maas & Westra 1984, 1985). [Photo - Flower, Fruit, Fruit.]
Age. Divergence within Anaxagorea may have begun ca 44 m.y.a. (Scharaschkin & Doyle 2005) or 57-16 m.y.a. (Pirie & Doyle 2012).
[Ambavioideae [Malmeoideae + Annonoideae]]: ray cells lacking druses; trunk leaves spiral; (outer staminodes +), inner staminodes 0; ovules with outer integument 4-6 cells across, inner integument 2-4 cells across, nucellar cap to 5 cells across; fruit berrylets, (monocarp abscission at the apex); seed symmetric, with perichalazal ring; ?endosperm cell walls with xyloglucans [thick, pitted - amyloid]. (map: from Aubréville 1974a; Trop. Afr. Fl. Pl. Ecol. Distr. 1. 2003.)
Age. This node has been dated to (84.4-)74.7(-63.6) m.y.a. (Su & Saunders 2009), (76.6-)68, 64.5(-53.0) m.y. (Erkens et al. 2009), 70-65 m.y.a. (Couvreur et al. 2011a) and 90-73 m.y.a. (Pirie & Doyle 2012).
2. Ambavioideae Chatrou, Pirie, Erkens & Couvreur
(Trunk leaves 2-ranked - Cleistopholis); anther connective ± tongue-like to peltate-truncate; carpels 3-8, stipe articulated, (extragynoecial compitum + - Cananga); ovules (1)2[lateral]-16/carpel, middle integument + (0), 4-6 cells across; (seed arillate), (endosperm ruminations lamelliform); n = 7, 8.
9/50: Drepananthus (26). Tropical, inc. Madagascar.
Age. Crown-group Ambavioideae have been dated to (80.9-)57.0(-52.3) m.y.a. (Surveswaran et al. 2010), (78-)69.4(-60.2) m.y. (Couvreur et al. 2011a), 59-27 m.y.a. (Pirie & Doyle 2012), and a little over 75 m.y. (Thomas et al. 2015).
[Malmeoideae + Annonoideae]: (polyacetylenes +); neolignans 0?; petioles short; anther connective peltate-truncate; tectum retiperforate, (exine infratectum columellate), outer foliation of nexine massive; stigma capitate.
Age. This node has been dated to (69-)66.7-56.6(-54.3) m.y. (Richardson et al. 2004), (78.1-)67.3(-55.2) m.y. (Su & Saunders 2009), 86-71 m.y.a. (Pirie & Doyle 2012), and (70.9-)57.4, 38.8(-28.3) m.y. (Thomas et al. 2015).
3. Malmeoideae Chatrou, Pirie, Erkens & Couvreur / The Short Branch Clade
(Prophyll single, adaxial-lateral); (inflorescence cymose); (outer A staminodial - Fusaea), (anther connectives not expanded/not covering the thecae); (pollen globose), (surface ± spiny), (disulcate/in- or cryptoaperturate - Miliuseae); (G 1), (stigma large/peltate); ovules 1[basal]-many/carpel; (tegmen with oil globules); endosperm ruminations spiniform (lamelliform); (mesotesta with transverse fibres only - Polyalthia); (inversion in the large single copy region - Miliuseae); n = ?
Ca 50/700: Polyalthia (100), Monoon (56), Pseuduvaria (50), Unoniopsis (45). Lowland tropics.
Age. The age of crown-group Malmeoideae has been dated to (66.1-)62.5-53.1(-49.5) m.y. (Richardson et al. 2004), (55.1-)39.8(-26.7) m.y. (Su & Saunders 2009), 70-62 or 54-34 m.y.a. (Pirie & Doyle 2012, q.v. for several other estimates), and (70.9-)57.4, 38.8(-28.3) m.y. (Thomas et al. 2015).
4. Annonoideae Rafinesque / The Long Branch Clade
(Lianes), (plant deciduous); (trunk leaves 2-ranked), (branch leaves spiral); (C 3); (anthers locellate), (inner staminodes + - Xylopia); pollen (in tetrads or polyads), (in/omniaperturate), (exine foliations numerous), orbicules usu. 0; (G connate, placentation parietal), (stigma sessile - Uvaria); ovules 1, 2, many/carpel; outer integument ca 4 cells across [Sten], (middle integument + - Artabotrys), (antipodal cells persisting); (fruit follicle/dehiscing abaxially); (seed arillate); endosperm ruminations lamelliform (irregular); n = 7-9.
Ca 50/1,500: Guatteria (180), Annona (120-175, soursop, sweetsop: inc. Rollinia), Xylopia (100-160), Uvaria (110-150), Monanthotaxis (95), Artabotrys (90), Goniothalamus ([50-]130), Duguetia (70-95), Fissistigma (60), Friesodielsia (38). Predominantly lowland tropics, rarely temperate.
Age. Crown-group Annonoideae may be (62.5-)60.2-51.1(48.7) (Richardson et al. 2004), (70.5-)59.6(-48.1) m.y. old (Su & Saunders 2009) or 80-64 m.y.a. (Pirie & Doyle 2012, also other estimates; see also Thomas et al. 2015).
Synonymy: Monodoraceae J. Agardh
To be assigned to the above two subfamilies.
acetogenins [antimicrobial] +; terminal cell of uniseriate hairs pointed (hairs stellate); (primary stem with continuous cylinder); cambium storied; (sieve tube plastids also with protein fibres); petiole bundle also annular; branched sclereids or fibres common; secretory cells +; inflorescence cymose (leaf opposed), or flowers axillary; flowers A (³3), (latrorse, introrse), tapetal cells amoeboid, multinucleate; (microsporogenesis successive); (pollen grains tricellular); G (3-)many, when 3 opposite outer P, stigma wet, extragynoecial compitum common; (nucellar cap 0); (sarcotesta +), endotesta crystalliferous, (with thin walled, longitudinal fibres); germination epigeal/crypto- or phanerocotylar.
Synonymy: Hornschuchiaceae J. Agardh
Floral formula - Anaxagoreoideae: * K 3; C 3 + 3; A many, + severalo; G 3-many.
Everything Else: * K 3; C 3 + 3; A many; G 1-many.
Evolution: Divergence & Distribution. Su and Saunders (2009) offer dates for additional splits in the family, focusing on Pseuduvaria, and Thomas et al. (2012) and Pirie and Doyle (2012) give many dates for divergences within both main subfamilies. Note that although stem age estimates of the subfamilies are in the 70-million year range, crown ages vary widely, the ages in Couvreur et al. (2011a) being the youngest, and those of Pirie and Doyle (2012, q.v. for other estimates) the oldest.
The biogeography and diversification of the family has been much studied (see also Doyle et al. 2004; Richardson et al. 2004; Su & Saunders 2009; Surveswaran et al. 2010; Thomas et al. 2015). Much diversification happened after the break-up of the continents and is Caenozoic in age, although rafting of the ancestors of Malmeoideae on India is perhaps a possibility (Thomas et al. 2015). Couvreur et al. (2011a) contrast speciation in Annonoideae and Malmeoideae. The former began to diversify ca 66 m.y.a. and the latter much later, ca 33 m.y.a.; the former has about twice as many species as the latter, even if rather paradoxically the latter may have a higher diversification rate - once it got going (see Couvreur et al. 2011a; Thomas et al. 2012, older, but similar disparity: both give other ages; Erkens et al. 2012). Malmeoideae-Miliuseae represent a major increase in diversification within the magnoliids as a whole (Massoni et al. 2015a).
In the Annonoideae, the Old World Uvaria may have originated (38.4-)31.6(-25.1) m.y.a. in Africa, whence it dispersed to other parts of the Old World (L. Zhou et al. 2012: HPD). Indeed, Thomas et al. (2014) suggest thatc there have been around 11 dispersals from Africa to Asia, and only one from Asia to Africa; Late Palaeocene to late Miocene are the suggested times. The large New World genus Guatteria has undergone much speciation in (Amazonian) South America perhaps 8.8-4.9 m.y. before present, having moved to South America from Central America, perhaps from Africa via Europe (Erkens 2007; Erkens et al. 2007a, b, 2009).
Erkens et al. (2012b; ?program) found little in the way of changes in diversification rates in the family, speciation behaving as if it were a random branching process, and so there was little need to invoke key innovations.
For pollen morphology and evolution, see Doyle (2009), Doyle et al. (2000) and especially Doyle and Le Thomas (1994), and for this and other aspects of floral morphology, see Doyle and Le Thomas (1996, 1997). Mols et al. (2004b) explored character evolution within Malmeoideae, while Chaowasku et al. (2014) optimised the distributions of a number of characters in Miliuseae. For the evolution of syncarpy, etc., in African Annonaceae, see Couvreur et al. (2008a).
Ecology & Physiology. Annonaceae are important lianes of the tropical South East Asian forests (Gentry 1991; Appanah et al. 1993), and there have been several origins of this habit within Annonoideae (Meinke et al. 2011); all told, ca 500 species of annonaceous lianes are known from the palaeotropics (Couvreur et al. 2015). Artabotrys (Xylopieae), one of these, has curved hooks on the ultimate branches; these are modified inflorescences. The orthotropic stems may have stout, paired and rather vicious straight thorns. The other lianes do not have hooks or thorns, and the extent of the development of the liane habit varies; another major liane clade includes Monanthotaxis, in Uvarieae (Guo et al. 2017).
The family is notably common in terms of both numbers of species (third in the list) and individuals in the Amazonian tree flora, but it includes only 4 of the 227 species that make up half the stems 10 cm or more d.b.h. in the forests (ter Steege et al. 2013). Guatteria, often a smallish tree, is diverse there, and like similar Amazonian taxa it has a rather short generation time (Baker et al. 2014).
Xylopia rubescens (Annonoideae) is one of the four common species mentioned growing in the ca 145,500 km2 of peat in the Cuvette Centrale in the Congo (Dargie et al. 2017).
Pollination Biology & Seed Dispersal. Saunders (2010: good photographs) summarizes variation in floral morphology in the context of pollination, and Gottsberger (2016) provides an extensive discussion on pollination in the family. Flowers in which the stamens are enclosed in some sort of bowl-shaped structure are common, and there are often floral rewards on the inner surfaces of the inner perianth whorl, and these may be in the form of nectar (Erbar 2014 and references). Pollination of the more or less odoriferous flowers is predominantly - and perhaps ancestrally - by small beetles. Thus neotropical members of Anaxagorea are pollinated by Colopterus, small nitidulid (sap) beetles (Gottsberger 2016 and references). Other insects - flies, thrips, bees, cockroaches, etc. - are also pollinators (Corlett 2004; Su et al. 2008; Saunders 2012; Gottsberger 1970, 2012, 2016). Large-flowered species of neotropical genera like Annona are pollinated by larger dynastid scarab beetles, e.g. Cyclocephala, although nitidulids may also be important pollinators (Nadel & Peña 1994; Gottsberger 2016). The odours produced by annonaceous flowers are diverse and include those of decaying animal tissues (Goodrich 2012; Jürgens et al. 2013 for the different odour bouquets; Gottsberger 2016). The tough, apically expanded connective that predominates in stamens of Annonoideae and Malmeoideae may protect the pollen from the depradations of unwanted visitors (Gottsberger 1999, 2012; Silberbauer-Gottsberger et al. 2003). The flowers of some Annonaceae show thermogenesis (Seymour 2001), and some kind of extracarpellary compitum - a suprastylar extragynoecial compitum - is common (Gottsberger 2016), althoough I do not know details of its distribution (Deroin 1991; Igersheim & Endress 1997).
Nearly all Annonaceae have perfect flowers, and protogyny will not prevent movement of pollen from one flower to another on the same plant (geitonogamy). However, all flowers on individual plants may be at either at the pistillate or at the staminate phase, so preventing selfing, a condition quite widely distributed within the family (Pang & Saunders 2014, 2015). The internal staminodes of Anaxagorea cover the gynoecium in the staminate floral phase, apparently preventing selfing (Gottsberger 2012; Saunders 2012).
Dispersal of fruit is predominantly by mammals and birds. The lianes of tropical South East Asia are notably important food resouces for frugivores because they fruit more or less continually (Leighton " Leighton 1983).
Vegetative Variation. The main axes of Annonaceae are often mixed (?Troll's model), initially being orthotropic and with spirally-arranged leaves, later being more or less plagiotropic with two-ranked leaves (see also Eupomatia), while taxa such as Asimina and Annona have orthotropic axes with 2-ranked leaves (Johnson 2003). Johnson and Stull (2014) outline variation in the family, and the optimisation above is based on their work. How Meiocarpidium (Ambavioideae) grows is unknown. In general, axillary branches depart from the stem slightly to one side of the axil. Branches generally have plagiotropic leaves, and in some Xylopia, etc., the plagiotropic branch systems are frondose and very beautiful.
Genes & Genomes. Substitution rates in chloroplast DNA have long been known to be higher in Annonoideae than in Malmeoideae, about three times higher being the estimate in Chatrou et al. (2014), hence their informal names, the long and short branch clades. This difference is also evident in nuclear rDNA (Hoekstra et al. 2016).
Morawetz (e.g. 1986b, 1988, see also Doyle & Le Thomas 1997) describe distinctive patterns of chromosome condensation in Annonaceae, which may well have some phylogenetic signal. For a chloroplast inversion in Miliuseae, see Arias et al. (2014b).
For the PEP subunit α rpoA gene, see Blazier et al. (2016).
There is probably intergeneric hybridization between Dasymaschalon and Friesodielsia, some species of the former grouping with the latter in chloroplast analyses, but Dasymaschalon is monophyletic in nuclear analyses (Guo et al. 2014).
Chemistry, Morphology, etc. Protoberberidine alkaloids are reported from Annonaceae (Wink 2008). Cork in the roots of Goniothalamus may be superficial (Blunden & Kyi 1974). The wood occasionally fluoresces. Terminal tracheids are fairly commonly silicified (Piperno 2006). For the petiolar anatomy of Anaxagorea, see Jovet-Ast (1942) and Maas and Westra (1984); it is unlikely that there are annular petiolar bundles, although the midrib anatomy can be complex. Tetrameranthus sometimes seems to have opposite leaves, and according to George Schatz (pers. comm.) it lacks plagiotropic branches and all branches have spirally-arranged leaves, while Chatrou et al. (2012) suggest that Annonoideae-Bocageeae, -Xylopieae and -Duguetieae have branches with spiral leaves.
The pollen tetrads can be very large and with a massive exine (Tsou & Johnson 2003 and references). There are reports that the pollen grains of both Annona and Asimina may germinate via the proximal pole (Hesse et al. 2009a), although in the former (and some other genera) individual grains of the tetrad may rotate during development (Tsou & Fu 2002, 2006; Lora et al. 2009b). Xylopia, like Anaxagorea also with follicles, has micropylar-arillate seeds (Corner 1976); other genera may also have reduced arils (Svoma 1997). Reports that the micropyle is formed by both integuments need to be confirmed (c.f. Svoma 1998b). Monodora (derived) has a rather thin outer integument, and anatomy of the seed coat of Ambavioideae with a third integument (Zwischenintegument) can be complex (Christmann 1986; see also Perisamy & Swamy 1961).
For an introduction - and much more - to Annonaceae, see the papers in Bot. J. Linnean Soc. 169(1). 2012, including Erkens et al. (2012a) for a comprehensive bibliography; see also Kessler (1993), Chartrou and He (199: Fusaea) and Bakker (2000a, b) for general information, and Maas et al. 2015) for the large genus Guatteria. Also Hegnauer (1964, 1989: chemistry), Jovet-Ast (1942: indumentum and anatomy), Junikka and Koek-Noorman (2007: bark anatomy), Koek-Noorman and Westra (2012: wood anatomy), van Setten and Koek-Noorman (1986: leaf anatomy), Sun et al. (2008: epidermal anatomy), van der Wyck and Canright (1956: anatomy), Fries (1919: inflorescence morphology), Deroin (1991b: stigmatic surface and carpel morphology), Steinecke (1993: esp. flower and fruit), Rudall and Furness (1997: tapetum), Endress (2011b: ovules), Deroin (1999a: receptacular vascular system), Couvreur et al. (2008b: Monodora group), Chaowasku et al. (2008: Miliusa et al.) and Doyle (2014a: summary), all pollen, Lora et al. (2009: infraspecific variation in number of pollen nuclei in Annona cherimola), Corner (1949, 1976), Svoma (1998a), van Setten and Koek-Noorman (1992) Corona Velásquez et al. (2016) and Galastri and Oliveira (2016), all ovules, fruits and seeds, and Okada and Ueda (1984) and Morawaetz (1986, 1988), esp. cytology. For floral (developmental) morphology, see van Heusden (1992), Ronse Decraene and Smets (1990b), Leins and Erbar (1980, 1982, 1996, 2010), Xu and Ronse De Craene (2010b), Endress (1975: carpel and stamen development), and Endress and Armstrong (2011: Anaxagorea), and for seed xyloglucans, see Kooiman (1960, 1971).
Phylogeny. See Doyle and Le Thomas (1994, 1996) for morphological phylogenies. As Doyle and Le Thomas (1997) emphasized, the inclusion of pollen characters yielded a topology very different from that when they were excluded, Anaxagorea and Ambavioideae being successively basal in the tree in the first case and deeply embedded in the second; the first topology largely agrees with that of molecular phylogenies. The position of Unonopsis on the tree has been somewhat erratic, perhaps because of ancient paralogy (Pirie et al. 2007). See Z.-D. Chen et al. (2016) for relationships among Chinese taxa. Although the topology above is generally recovered, Chatrou et al. (2014) found a clade [Annonoideae + Ambavioideae].
Scharaschkin and Doyle (2005, 2006) provide a molecular phylogeny of Anaxagorea that is integrated with morphological variation, see . For relationships in Ambavioideae, see Surveswaran et al. (2010); the basic phylogenetic structure seems to be [Meiocarpidium [Tetrameranthus et al. + Cananga et al.]].
Two major clades make up the rest of the family (see also Richardson 2004). Malmeoideae have relatively little internal molecular divergence (hence its early name, the short-branch clade: Mols et al. 2008; Xue et al. 2011; Thomas et al. 2015). They are not very speciose, mostly lacking large genera aside from Polyalthia s.l. which is polyphyletic (Richardson et al. 2004). New World members of this clade form a monophyletic group (Pirie et al. 2006). For Pseuduvaria, see Su and Saunders (2006) and Su et al. (2008, 2010), while for the relationships and dismemberment of Polyalthia, see Xue et al. (2011, 2012). Chaowasku et al. (2014) clarify relationships within the large clade that makes up Miliuseae with its cryptoaperturate/disculate pollen grains, although support for the branches along the spine was still somewhat ambiguous. Most of this clade is South East Asian-Malesian; for relationships in the New World members, see Ortiz-Rodriguez et al. (2016).
Annonoideae show more internal molecular divergence (hence its name, the long branch clade: see also J. A. Doyle et al. 2004; Pirie et al. 2005; Thomas et al. 2015). Uvaria is polyphyletic (Mols et al. 2004a), and L. Zhou et al. (2009a, esp. b, 2010) suggested that its limits be extended; geography and phylogeny correlate quite well. The limits of genera like Dasymaschalon and Friesodielsia were initially unclear (Wang et al. 2012: independent loss and subsequent parallel evolution in taxa that have lost their inner petals), but these are being clarified (Guo et al. 2017). For Guatteria, see Erkens (2007), Erkens et al. (2007a, b); G. heteropetala and G. anomala are successively sister to the res of the genus. Tang et al. (2015: character optimisations; see also Nakkuntod et al. 2009) focussed on Goniothalamus, where there is quite extensive variation in the fruit.
Classification. The classification outlined by Chatrou et al. (2012) is followed here, although they also recognize tribes; their principles of classification are clearly explained. The limits of genera and hence the numbers of their included species in Annonoideae seem particularly uncertain, but for a key to genera there and elsewhere in the family, see Couvreur et al. (2012). L. Zhou et al. (2010) clarify the limits of Uvaria, Xue et al. (2011, 2012) those of Polyalthia, while Surveswaran et al. (2010) discuss generic limits in the ambavioid clade. For a checklist of the New World species of the genus, see Maas et al. (2011); Annonbase should also be consulted.