EMBRYOPSIDA Pirani & Prado
Gametophyte dominant, independent, multicellular, not motile, initially ±globular; showing gravitropism; acquisition of phenylalanine lysase [PAL], 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, sporopollenin + laid down in association with trilamellar layers [white-line centred lamellae; tripartite lamellae], >1000 spores/sporangium; nuclear genome size <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.
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; sporophyte with polar transport of auxins, 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].
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]; (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; 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]; 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); 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; ycf2 gene in inverted repeat, mitochondrial trans- nad2i542g2 and coxIIi3 introns present; 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 apical meristem intermediate-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 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 , 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 very small [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.
[MONOCOTS [CERATOPHYLLALES + EUDICOTS]]: (extra-floral nectaries +); (veins in lamina often 7-17 mm/mm2 or more [mean for eudicots 8.0]); (stamens opposite [two whorls of] P); (pollen tube growth fast).
[CERATOPHYLLALES + EUDICOTS]: ethereal oils 0.
EUDICOTS: (Myricetin, delphinidin +), asarone 0 [unknown in some groups, + in some asterids]; root epidermis derived from root cap [?Buxaceae, etc.]; (vessel elements with simple perforation plates in primary xylem); nodes 3:3; stomata anomocytic; flowers (dimerous), cyclic; protandry common; K/outer P members with three traces, ("C" +, with a single trace); A ?, filaments fairly slender, anthers basifixed; microsporogenesis simultaneous, pollen tricolpate, apertures in pairs at six points of the young tetrad [Fischer's rule], cleavage centripetal, wall with endexine; G with complete postgenital fusion, stylulus/style solid [?here]; seed coat?
[PROTEALES [TROCHODENDRALES [BUXALES + CORE EUDICOTS]]]: (axial/receptacular nectary +).
[TROCHODENDRALES [BUXALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.
[BUXALES + CORE EUDICOTS]: ?
CORE EUDICOTS / GUNNERIDAE: (ellagic and gallic acids +); leaf margins serrate; compitum + [one position]; micropyle?; γ whole nuclear genome duplication [palaeohexaploidy, gamma triplication], PI-dB motif +, small deletion in the 18S ribosomal DNA common.
[ROSIDS ET AL. + ASTERIDS ET AL.] / PENTAPETALAE: root apical meristem closed; (cyanogenesis also via [iso]leucine, valine and phenylalanine pathways); flowers rather stereotyped: 5-merous, parts whorled; P = calyx + corolla, the calyx enclosing the flower in bud, sepals with three or more traces, petals with a single trace; stamens = 2x K/C, in two whorls, internal/adaxial to the corolla whorl, alternating, (numerous, but then usually fasciculate and/or centrifugal); pollen tricolporate; G , G  also common, when [G 2], carpels superposed, placentation axile, style +, stigma not decurrent; compitum +; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; RNase-based gametophytic incompatibility system present; floral nectaries with CRABSCLAW expression; (monosymmetric flowers with adaxial/dorsal CYC expression).
[DILLENIALES [SAXIFRAGALES [VITALES + ROSIDS s. str.]]]: stipules + [usually apparently inserted on the stem].
[SAXIFRAGALES [VITALES + ROSIDS]] / ROSANAE Takhtajan / SUPERROSIDAE: ??
[VITALES + ROSIDS] / ROSIDAE: anthers articulated [± dorsifixed, transition to filament narrow, connective thin].
ROSIDS: (mucilage cells with thickened inner periclinal walls and distinct cytoplasm); if nectary +, usu. receptacular; embryo long; chloroplast infA gene defunct, mitochondrial coxII.i3 intron 0.
ROSID II / MALVIDAE / [[GERANIALES + MYRTALES] [CROSSOSOMATALES [PICRAMNIALES [SAPINDALES [HUERTEALES [MALVALES + BRASSICALES]]]]]]: ?
Age. Moore et al. (2010: 95% HPD) suggest ages of (104-)102(-97) m.y. for crown-group malvids, Xue et al. (2012) an age of around 84 m.y., while about 103.2 m.y. is the age in Naumann et al. (2013), ca 118.3. m.y. in Hohmann et al. (2015: note topology) and ca 121 m.y. in Foster et al. (2016: q.v. for details).
Evolution. Divergence & Distribution. Hengchang Wang et al. (2009: penalized likelihood dates) suggested that rapid radiation within Malvidae occurred (113-)107-83(-76) m.y. ago.
Phylogeny. See the Pentapetalae and Saxifragales pages for further discussion on the relationships of the malvids and of the [Geraniales + Myrtales] clade in particular. An ancestor of the malvids may have been involved in an ancient hybridization with an ancestor of the fabids, for which, see the Zygophyllales page.
[GERANIALES + MYRTALES]: ellagic acid +; K persistent in fruit.
Age. The age of this node is variously 89-83 m.y. (Anderson et al. 2005), (103-)100(-97) m.y. (Wikström et al. 2001); (114-)107(-100) or (90-)83(-76) m.y. (Hengchang Wang et al. 2009); ca 108 m.y. (Magallón & Castillo 2009: topology uncertain); (121-)115, 107(-103) or (122-)116, 108(-104) m.y. (Bell et al. 2010: topology uncertain); (99-)91(-77) m.y. (N. Zhang et al. 2012), or about 79 m.y. (Xue et al. 2012). Ca 123 and 88.2 m.y. are ages suggested by Sytsma et al. (2004 and 2014 respectively), (124.8-)123.6(-122) m.y. by Berger et al. (2015), and around 92.5 m.y. by Naumann et al. (2013).
GERANIALES Berchtold & J. Presl Main Tree.
Vessel elements with simple perforation plates; nodes also 3<:3<; lamina margins gland-toothed; inflorescence cymose; nectary outside A; A obdiplostemonous; G opposite petals, ?style, stigma dry; outer integument (largely dermal in origin), 2-3 cells across, inner integument 2-3 cells across; fruit capsular, ?dehiscence; seed testal. - 2 families, 17 genera, 836 species.
Age. Geraniales can be dated to 86-80 m.y. (Anderson et al. 2005); other estimates are provided by Wikström et al. (2001), (98-)94, 88(-84) m.y.a., Hengchang Wang et al. (2009), ca 106.5 m.y., and Hohmann et al. (2015), (109-)103(-97), (74-)68(-62) m.y.(a muddle here -sorry), Bell et al. (2010), (106-)93, 87(-74) m.y., and Park et al. (2015a), ca 95.4 m.y., while ca 104 m.y. is the estimate in Sytsma et al. (2004). Palazzesi et al. (2012) suggested just under 50 m.y., but c.f. Sytsma et al. (2014) who reanalyzed the same data and came up with an age of 89-76 m.y., while around 109.5 m.y. is the estimate in Tank et al. (2015: Table S2).
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. Geraniales are poorly understood, and although a smallish group, they are morphologically quite heterogeneous, which, coupled with lingering uncertainty over their exact phylogenetic position and internal relationships, still makes thinking of apomorphies difficult (Kubitzki 2006a). Palazzesi et al. (2012) discuss the evolution of the whole group in some detail, but Sytsma et al. (2014) should be consulted fot a reanalysis of their data, which yielded a number of different and mostly significantly older dates; adding rosid stem priors was a major cause of the differences.
Genes & Genomes. Details of the distribution of the chloroplast rpl16 intron in the order are unclear (see Geranioideae: c.f. Downie & Palmer 1992b).
Chemistry, Morphology, etc. Bortenschlager (1967) provides a comprehensive pollen survey of Geraniaceae in the old sense, i.e. including things like Dirachmaceae (Rosales), also Vivianiaceae which, although no longer in Geraniaceae, at least are still in Geraniales, while none of the nine geranialean families studied by Oltmann (1971) is still included in Geraniales. For references to obdiplostemony, see Ronse De Craene and Bull-Hereñu (2016).
Phylogeny. Savolainen et al. (2000a) found the order to be monophyletic, but with only 52% support (see also Savolainen et al. 2000b). The tree prior to Oct. 2012, but names as used here - [Geraniaceae [[Bersameae + Francoeae] [Vivianieae + Ledocarpeae]]] - was based on these and other studies, although sampling was inconsistent, etc.; Bersameae included Greyia. However, the clade [Greyieae + Francoeae] has been strongly supported (Morgan & Soltis 1993; Price & Palmer 1993; Soltis & Soltis 1997), but Soltis et al. (2007a) found the set of relationships [Geraniaceae [Viviana [Bersama [Francoa + Greyia]]]] (see also Bell et al. 2010). Palazzesi et al. (2012: trnL-F, ITS) on the other hand, recovered a tree [Geraniaceae [Bersameae [Vivianieae [Francoeae + Greyieae]]]], with support for all clades strong except that for the [Vivianieae [Francoeae + Greyieae]] clade, although the chronogram is based on a tree with the topology [Geraniaceae [Vivianieae [Bersameae [Francoeae + Greyieae]]]].
Classification. Geraniaceae and Francoaceae-Vivianieae have a layer of small hypodermal druse-containing cells in the calyx (Kenda 1956). Indeed Weigend (2006: 217) suggests that there might be "a close and possibly exclusive relationship between Geraniaceae and Ledocarpaceae [= Vivianieae]." He lists numerous characters suggesting such a relationship, such as that in both the basal ovules in the ovary tend to develop into seeds (although Boesewinkel 1997 mentioned that it was the upper ovules of Caesarea that developed into seeds), and their fruits are septicidal or septifragal (Boesewinkel 1997 describes them [apart from Rhyncotheca] as being loculicidal). However, the nature of the campylotropy of the ovules differs and the fruits of Rhyncotheca differ rather strongly from the superficially similar fruits of Geraniaceae (although both do have a column), etc.. Nevertheless, there are a number of similarities between the two.
Previous Relationships. As noted above in the discussion of pollen morphology (Oltmann 1971, see table on p. 145, Geraniales were previously a very heterogeneous group. The circumscription of the clade adopted here is somewhat unexpected, largely because Geraniaceae and Oxalidaceae have previously been considered very close (e.g. Cronquist 1981). Indeed, although Cronquist included only five families in his Geraniales, they are here placed in four orders in both asterids and rosids. Geraniaceae in particular included genera now widely dispersed in the rosids, but it has not previously been associated with a number of taxa included in Francoaceae below.
Includes Francoaceae, Geraniaceae.
Synonymy: Francoales Martius, Greyiales Takhtajan, Ledocarpales Doweld, Melianthales Doweld - Geranianae Reveal - Geraniopsida Meisner
GERANIACEAE Jussieu, nom. cons. Back to Geraniales
Herbs; hydrolysable tannins +; leaves spiral, pinnate, leaflets not articulated, secondary veins [inc. on leaflets] often palmate; inflorescence cymose, often pseudoumbellate; C contorted; nectaries opposite sepals, vascularized; pollen ?often starchy; ovules often campylotropous, micropyle zig-zag; K persistent in fruit; endotesta palisade, with light line, crystalliferous, much thickened, unlignified, exotegmen palisade, lignified, anticlinal walls sinuous; 4 kb inversion in chloroplast genome, reduced single copy region.
7[list]/805 - 2 groups below. Temperate and warm temperate. [Photos - Collection]
Age. Palazzesi et al. (2012) opined that Hypseocharis diverged from the rest of the family (42.8-)36.9(-5.7) m.y.a., although a reworked estimate is (72-)62(-52) m.y. (Sytsma et al. 2014), while Fiz-Palacios et al. (2008) suggested an age of 55 m.y., Park et al. (2015a) an age of ca 51 m.y., and Sytsma et al. (2004) an age of around 85 m.y. for this split.
1. Hypseocharis Remy
Perennial ± acaulescent herbs, tuberous, or thick taproots; anatomy?; stipules 0; A 5, 15 [10 in pairs opp. C], ca 12 ovules/carpel, style filiform, stigma capitate, ?surface; fruit a loculicidal capsule (septicidal, almost with mericarps - H. tridentata), filaments also persistent; endosperm scanty, embryo cochlear, cotyledons spirally twisted; n = ?
1/1-3. S.W. Andean South America (Map: from Slanis & Grau 2001).
Synonymy: Hypseocharitaceae Sweet
2. Geranieae Arnott
(Shrubs; stem succulents, geophytes); (petroselenic acid + - Geranium); root hypodermal cells lacking Casparian strips [Pelargonium]; young stem with separate vascular bundles; (vessel elements with scalariform perforation plates); wood often rayless; ?nodes; stem often jointed; petiole bundles annular (medullary bundles +); hairs glandular; cuticle waxes 0 (rodlets); (stomata anisocytic); leaves (opposite), also simple and lobed, lamina vernation conduplicate-plicate, (petiolar spines + - Sarcocaulon), stipules 2, often well developed, interpetiolar or cauline, colleters +; (flowers monosymmetric); K quincuncial [Geranium], aristate; C (4), often salverform, (petals fringed); (nectariferous spurs +), (adaxial nectary only, "adnate" to pedicel - Pelargonium), (nectary opposite C - Monsonia); A (15 [=5 x ], 2-7 [Pelargonium]), (antepetalous whorl staminodial), filaments ± connate basally; (tapetum amoeboid); pollen grains tricellular, (tricolpate), surface reticulate or (interwoven-)striate, 40-140 µm long; G [(2-)5], true style short, stout, hollow [?always], stigma lobed; ovules 1-2/carpel, apical, campylotropous by development of cells of the inner integument, (micropyle exostomal; ovules apotropous, parietal tissue ca 4 cells across, (nucellar cap +); embryo sac invades and obliterates apical nucellar tissue; fruit septicidal, upper part of ovary elongating [= "stylar" beak], mericarps curl upwards and separate from columella, whether or not seeds disperse separately; exotestal cells undistinguished, stellate, stomata +, (endotegmen slightly lignified); endosperm 0, embryo chlorophyllous [Geranium], curved, cotyledons accumbent, longitudinally folded (incumbent, flat - Pelargonium), radicle ± as long as rest of embryo; n = 4, 7-14, etc; inversions in cp DNA, trnT-GGU gene loss, group II intron between nad1 b/c exons, rpl16 and rps16 intron loss, etc.; sporophytic incompatibility system present.
5/865: Geranium (430), Pelargonium (280), Erodium (80), Monsonia (40: inc. Sarcocaulon). Temperate and warm temperate, esp. southern Africa (map: from van Steenis & van Balgooy 1966; Hultén 1971; Wickens 1976; Meusel et al. 1978; Trop. Afr. Fl. Pl. Ecol. Distr. 1. 2003; Aedo et al. 2005).
Age. The crown group age of Geranioideae is estimated at (71-)54, 48(-33) m.y. (Bell et al. 2010) or some (50-)48, 37(-34) m.y. old (Wikström et al. 2001); Palazzesi et al. (2012) suggest an age of slightly less than 30 m.y. and Park et al. (2015a) an age of ca 35 m.y., but (57-)48(-39) m.y. is the figure in Sytsma et al. (2014), see also 47-38 m.y. in Fiz et al. (2008) and as much as ca 67.8 m.y. in Hohmann et al. (2015), similar to Sytsma et al. (2004).
Synonymy: Erodiaceae Horaninow
Evolution. Divergence & Distribution. Diversification of Pelargonium (and Monsonia), some 155 species of which are succulents (Nyffeler & Eggli 2010b), in South Africa seems to have occurred ca 30-10 m.y. before present as aridification set in, while diversification of the Geranium-Erodium clade occurred at roughly the same time in Eurasia and the Mediterranean, perhaps in response to climate change and mountain uplift there (Fiz et al. 2008); however, Fiz-Palacios et al. (2010) suggest that the ancestral area of Erodium was Asia, where it arose ca 18 m.y. ago. Palazzesi et al. (2012) in general offer younger estimates for splits within Geranioideae, but c.f. Sytsma et al. (2014) for a reanalysis of their data.
Struck (1997) and Bakker et al. (1999, 2000, 2004, 2005) discuss the phylogeny and diversification of Pelargonium in the Cape region; there is striking vegetative and floral variation, and almost 100 species are geophytes (Procheŝ et al. 2006). Leaf shape and scent is notably variable, and Jones et al. (2009) discuss foliar evolution. Divergence of the Cape fynbos clades of Pelargonium may have occurred some (13.6-)10.6(-3.7) m.y.a., diversification in the Succulent Karoo starting a little earlier (Verboom et al. 2009). All told, some 222 of the 280-300 species of Pelargonium are restricted to southern Africa (ca 290 species for the family as a whole - Johnson 2010), and it is a major element of the endemic flora of the Cape floristic region (Albers & Becker 2010 for a summary).
Ecology & Physiology. Geranium viscosissimum has glandular hairs and may be protocarnivorous, being able to digest proteins (?source of enzymes) and take up at least some of the products (Spomer 1999); the ability of plants with such hairs to digest at least some proteins is quite widespread.
Pollination Biology & Seed Dispersal. Some southwest African Geraniaceae are pollinated by three species of (extremely) long-tongued dipteran Nemestrinidae flies, overall, perhaps 25% of the species may be so pollinated (Manning & Golblatt 1996, 1997; Goldblatt & Manning 2000). Pelargonium in southern Africa is pollinated by a diversity of visitors (Struck 1997). A number of species of Geranium, at least, are revolver flowers. Thus in species like G. robertianum with a salverform corolla the flower develops in such a way that each "tube" is made up of six adjacent parts from four floral whorls - a remarkable example of synorganisation that does not involve any fusion of parts (Endress 2010d). Pollination in G. thunbergii, at least, is promiscuous, bees, flies and butterflies all being involved and they are inconstant from year to year (Kandori 2002).
The two adaxial petals of Pelargonium alone may bear markings, rather than the abaxial petal(s), as is common in flowering plants. Darwin (1859) noted that the central flower of a Pelargonium inflorescence might lose its adaxial markings and also its nectary. This would be expected of a peloric flower which has become "ventralised", i.e. the morphology of the abaxial sector of the flower extends to the adaxial sector, so the markings on the adaxial petals and the adaxial nectary disappear. For nectaries, see also Vogel (1998c).
Whether seeds of Geranioideae are catapulted or mericarps are the unit of dispersal, the fruit wall has a stiff outer layer and an inner layer that contracts as it dries, the awn coiling and bending as a result (Abraham & Elbaum 2013). The awn of the mericarp may be coiled (e.g. Erodium, some Geranium), and hygroscopic movements of the awn may result in the seeds being "planted" in the soil, as in some Poaceae (Stamp 1989 and references), while hairs on the awn may aid in wind dispersal (Abraham & Elbaum 2013). Yeo (1984) discussed fruit dehiscence in Geranium in particular, linking it to the taxonomy of the genus. Physical dormancy of seeds is common in the family (Gama-Arachchige et al. 2010).
Vegetative Variation. Leaf morphology is notably variable within Pelargonium (Nicotra et al. 2011).
Genes & Genomes. Palmer et al. (1987) noted extensive expansion of the inverted repeat (IR) in Pelargonium chloroplast genome, and the remarkably extensive changes there in Geraniaceae are outlined by Weng et al. (2013). The chloroplast genome may greatly expand, largely because of the IR expansion, and although the IR is the largest known for any flowering plant in Pelargonium (P. hortorum has the largest chloroplast genome known), it is sometimes entirely absent (in Erodium). Indeed, the IR may have been lost twice in Erodium, and an IR has also been regained, as in E. absinthoides (Blazier et al. 2016b: see also Thismia-Thismiaceae). There are also very extensive rearrangements, duplications (whole genome or smaller-scale), and increases in GC content (Erodium has the highest GC content in angiosperms - Blazier et al. 2016b) and substitution rates, as well as other changes, and ndh genes in the chloroplast may be lost (Chumley et al. 2006; Guisinger et al. 2008, 2011: sampling not bad; Jansen 2009 [summary]; Weng et al. 2013; J. Wang et al. 2015; Zhu et al. 2015). It is noteworthy that this variation occurs within genera and species, taxa like Erodium carvifolium and California showing little change, although the former has has lost its inverted repeat (Weng et al. 2013). Guisinger et al. (2011) suggest that this variation is the result of relaxed selection after improper DNA repair caused by mutation(s) in nuclear DNA-repair genes. For the PEP subunit α rpoA gene, see Blazier et al. (2016a).
Parkinson et al. (2005) and Bakker et al. (2006a) found great increases in the rate of evolution of the mitochondrial gene nad1 throughout Geranieae, especially in Pelargonium, but not in Hypseocharis (see also Palmer et al. 2000). This has been observed in other mitochondrial genes, as well (Mower et al. 2007; Guisinger et al. 2008). Indeed, the mitochondrial genome in Geranium is in a considerable state of flux. Not only have mitochontrial genes like ribosomal protein and succinate dehydrogenase genes moved from the mitochondrion to the nucleus in Erodium (Adams & Palmer 2003), but the mitochondrial genome has acquired material from both parasitic (Orobanchaceae, Cuscuta) and non-parasitic (Euhorbiaceae-Acalyphoideae, Rubiaceae-Rubioideae) flowering plants alike within the last 6 m.y. or so (Park et al. 2015a). Weng et al. (2012) observed that both plastid and mitochondrial genes had accelerated substitution rates, but noted that the rate might not be the same throughout the phylogeny or through the whole gene and it might be the result of either increased mutation rate or of selection. J. Zhang (et al. 2014) found coordinated evolution between nuclear and plastid genes both involved in the synthesis of plastid encoded RNA polymerase (PEP).
Biparental transmission of plastids has been recorded from Pelargonium, at least, and in hybrids, incompatability between chloroplasts from one parent and the hybrid genome may result in the death of those chloroplasts and thus to variegation (Weihe et al. 2009; see also Wicke et al. 2011; Apitz et al. 2013; J. Zhang et al. 2015).
Chemistry, Morphology, etc. For nodal anatomy in Geranieae, see Kumar (1977). Although the nodes are described as being trilacunar and variants, from the illustrations at least some species seem to have split laterals. Growth can be sympodial, axillary buds successively evicting the terminal buds (Kumar 1977).
Boesewinkel (1988) described the corolla of Hypseocharis as being often imbricate, while Weddell (1861: vol. 2: 289) illustrated it as being contorted (see also Takhtajan 1997). Monsonia may have nectaries axillary to the sepals or on the abaxial bases of the stamens (Aldasoro et al. 2001). When there are fifteen stamens, there are antepetalous stamen pairs, as is common in obdiplostemony (Ronse Decraene et al. 1996; see also Rama Devi 1991), or there may be five groups of three connate stamens (Aldasoro et al. 2001). Campylotropy is by inpushing of the inner integument (Albers & Van der Walt 2006 and references).
Some general information is taken from Yeo (1990) and Albers and Van der Walt (2006), and on Monsonia, perhaps paraphyletic, from Aldasoro et al. (2001), on Hypseocharis, from Slanis and Grau (2001); for chemistry, see Lis-Balchin (2002), for petroselenic acid in particular, see Tsevegsuren et al. (2004), for floral morphology, see Erbar (1998), for nectaries, see Link (1990), for pollen, see Verhoeven and Marais (1990), for ovule morphology, see Mauritzon (1934), for embryology, see L. L. Narayana (1970), for ovule and testa development, see Boesewinkel and Been (1979), and for seed coat, see Tokarski (1972: Geranium, also fruits), Meisert et al. (2001) and Gama-Arachchige et al. (2010: also dormancy).
Phylogeny. Hypseocharis is sister to the other members of the family (e.g. Price & Palmer 1993; Bakker et al. 1998). The genus is in need of further study; if H. tridentata, with septicidal (and ventricidal) capsule dehiscence, is sister to the rest of the genus, simple optimisation of fruit characters on the tree becomes interesting. Other relationships are [Pelargonium [Monsonia [Geranium + Erodium]]] (see also Palazzesi et al. 2012; J. Zhang et al. 2015); the position of the monotypic California is unclear (Fiz et al. 2008).
For a phylogeny of Erodium, see Fiz et al. (2006); there has been substantial dispersal. Within Pelargonium A 2-7, either x = 11, chromosomes 1.5³ µm long or x = 9, chromosomes 1.5-3.0 µm long; for a well-sampled phylogeny, see Röschenbleck et al. (2014).
Classification. Recognising Hypseocharis as a family was an option in A.P.G. II (2003) and Palazzesi et al. (2012) keep Hypseocharitaceae separate, but the family is small and reasonably included in Geraniaceae (see A.P.G. 2009). Hypseocharis has also been placed in a monotypic order, Hypseocharitales (Takhtajan 1997), although mercifully placed near Geraniales.
Röschenbleck et al. (2014) provide an infrageneric classification of Pelargonium.
Previous Relationships. Hypseocharis used to be included in Oxalidaceae (Hutchinson 1973; Cronquist 1981), but nectaries, testa anatomy, etc., place it unambiguously here (e.g. Boesewinkel 1988; Rama Devi 1991). Also, its leaflets are not strongly articulated with the petiole, as they are in Oxalidaceae. On the other hand, Geraniaceae used to include taxa like Biebersteiniaceae (Sapindales) and Dirachmaceae (Rosales). For suggested relationships between Geraniaceae and Francoaceae-Vivianieae, see below.
Botanical Trivia. The geranium of the window sill is really a Pelargonium.
FRANCOACEAE A. Jussieu, nom. cons. Back to Geraniales
Trees to perennial herbs; at least traces of inulin +; leaf insertion rather broad; inflorescence terminal, racemose; micropyle endostomal.
9[list]/31; four groups below. Africa, South America.
Age. Wikström et al. (2001) estimated the age of this node at (74-)67, 59(-52) m.y., and while comparable estimates in Palazzesi et al. (2012) are only (42.8-)31.4(-20.2) m.y., those in Bell et al. (2010) are (94-)77, 70(-51) m.y., in Sytsma et al. (2004) around 85 m.y., and that in Tank et al. (2015: Table S2) is around 94.4 m. years. The ages in Sytsma et al. (2004) and Park et al. (2015a) are for the topology [Viv. [Franc. + Ber.]].
1. Bersameae Planchon
Shrubs to trees; odoriferous [nasty, mustard], ellagic acid, glucuronide triterpenoid saponins, bufadienolides + [cardiac glycosides]; cork cambium subepidermal to pericyclic; medullary vascular bundles + (0); nodes 5-10:5-10; petiole with ring of bundles (cortical or medullary bundles +); styloids +; cuticle waxes usu. 0; leaves odd-pinnate, leaflets articulated, vernation conduplicate, secondary venation pinnate, margins strongly serrate to entire, (base not very broad - Bersama), stipules lateral, or single, intrapetiolar; inflorescence terminal or axillary, (with conspicuous sterile flowers at apex); flowers ± monosymmetric, resupinate [median sepal abaxial]; K 5, or  + 3, adaxial weakly spurred or not, C 4-5, clawed, unequal, recurved or not; nectary large, adaxial or annular, vascularized; A 4-5, (connate basally), dorsifixed, anther endothecium not fibrous [Melianthus], tapetal cells 3-nucleate; G [(3-)4-5(-7)], glandular hairs inside the loculus, style impressed, long, stigma punctate or capitate; ovules 1-5/carpel, axile or basal, apotropous to pleurotropous, ?campylotropous, parietal tissue ca 11 cells across, outer integument 16-20 cells across; fruit a loculicidal capsule; (seed arillate - Bersama); seed testal, exotesta palisade, crystalliferous, outer wall thick, tegmen crushed; endosperm thick- or thin walled, starchy or with xyloglucans [thick, pitted - amyloid - Melianthus], embryo small to medium, suspensor 0; n = (18) 19.
2/8. Africa (map: modified from Culham et al. 2007, see Trop. Afr. Fl. Pl. Ecol. Distr. 6. 2011). [Photo - Inflorescence, Inflorescence.]
Age. Crown-group Bersameae are (33.8-)26.9(-20.0) m.y. (Linder et al. 2006), (14.9-)10(-5.7) m.y. (Palazzesi et al. 2012) or (20-)14.4(-10) m.y. (Sytsma et al. 2014).
Synonymy: Bersamaceae Doweld, Melianthaceae Horaninow, nom. cons.
Previous Relationships. Melianthaceae were included in Sapindales by Cronquist (1981), who dismissed any idea of a relationship between them and Greyiaceae.
[Vivianieae [Greyieae + Francoeae]]: stipules 0; anthers basifixed; fruit a septicidal capsule.
2. Vivianieae Klotzsch
(Thorns +); ?inulin; ?nodes; wood rayless; leaves opposite, usu. pinnate, a line across the stem at the node; K aristate, C contorted; pollen grains spherical, 23-40 µm long, polypantoporate, with microspines; style short, style branches/stigmas separate, long, stigma dry, margins ± revolute; ovule with parietal tissue ca 6 cells across, (nucellar cap 2 cells across), obturator as hairs on funicle; exotesta and endotegmen more or less tanniniferous; endosperm ± copious, walls thick, pitted, embryo curved.
4/18. W. South America, S. Brasil.
Age. Crown-group Vivianeae are about 27.5 m.y.o. (Palazzesi et al. 2012) or (44-)35(-28) m.y.o. (Sytsma et al. 2014).
2A. Viviania Cavanilles
Woody herb (annual); chemistry?; cork?, cambium storied; nodes 1:1; glandular hairs +; cuticle waxes ± band-like or 0; lamina white-hairy below, secondary veins subpalmate; (flowers 4-merous); K valvate, basally connate, strongly 8- or 10-ribbed; (C 2-lobed); nectary glands alternating with C; (A 4, 5, 15); G [(2) 3], odd member abaxial; ovules 2/carpel, superposed; seed (hairy), raphe tanniniferous; (exotegmen thick-walled, elongated); endosperm copious, initially with some starch, embryo chlorophyllous, root long; n = 7.
1/6. Chile, S. Brasil (map: from Lefor 1975).
Synonymy: Vivianiaceae Klotzsch
2B. Balbisia Cavanilles, etc.
Shrubs; anatomy?; cuticle waxes as platelets; (leaves simple); epicalyx + or 0; (K acute; C 0); (pollen inaperturate - Balbisia, Wendtia); nectary 0; G [3, 5], opposite sepals, stigmas drying dark; ovules 2 collateral or superposed-many/carpel, nucellar cap +; (fruit septicidal or more or less septifragal); (exotesta of slime cells - Balbisia); endosperm scanty (thin-walled), cotyledons spiral (straight); embryo colour?; n = 9.
3/12. W. South America, especially the Andes (map: modified from Culham 2007).
Synonymy: Ledocarpaceae Meyen, Rhyncothecaceae Jussieu
[Greyieae + Francoeae]: inflorescence with sterile bracts at apex; bracteoles 0; A weakly secondarily obdiplostemonous, endothecium surrounds thecae; ovary sulcate; ovules many/carpel, pleurotropous; endotesta fibrous, anticlinal walls thickened and lignified.
Age. This node is dated at (45-)38(-31) m.y. (Wikström et al. 2001), (17.7-)11.2(-5.9) m.y.a. (Palazzesi et al. 2012, but c.f. Sytsma et al. 2014 - [35-]27[-15] m.y.), or (32-)19(-8) m.y. (Bell et al. 2010).
3. Greyieae Gürke
Shrubs to small trees; ellagic acid, B-ring deoxyflavonoids +; cork cambium ± pericyclic; (largely phloic medullary bundles +); cambium storied; pericyclic fibres +; nodes ca 9:9, some bundles beginning to leave at the bottom of the internode below; petiole bundle arcuate, also peripheral cortical bundles; raphides +; cuticle waxes usu. 0; leaves simple, outer cortex detaching from stem along with petiole and lamina, lamina vernation conduplicate, secondary veins palmate, margin bluntly serrate, teeth hydathodal, petiole terete; flowers ?resupinate [median sepal abaxial]; K 5, imbricate, C 5, imbricate; nectaries 10, stalked, peltate- or anvil- shaped; A long-exserted; G [(4-6)], ovary furrowed, opposite C or K, style continuous with ovary, long, stigma slightly expanded and ridged, wet; micropyle exo- or endostomal, outer integument 3-7 cells across, inner integument 2-4 cells across, hypostase massive; fruit valves also opening internally; exotesta crystalliferous, outer wall thick; endosperm starchy, thick-walled; n = 16-17.
1/3. South Africa, Swaziland. [Photo - Inflorescence.]
Age. Divergence between the extant species of Greyia is put at a mere (0.8-)0.4(-0.07) m.y.a. (Palazzesi et al. 2012).
Synonymy: Greyiaceae Hutchinson, nom. cons.
4. Francoeae Spach
Perennial herbs; flavonols, tannins of any sort 0, anthocyanin in roots, inulin?; cork ?; young stem with pseudosiphonostele, endodermoid layer +; nodes 3:5; petiole bundle arcuate, with lateral annular bundles; hairs uniseriate, secretory; leaves pinnate or simple, lamina vernation conduplicate-plicate, (secondary veins pinnate); inflorescence scapose, (branched); flowers poly- or monosymmetric; K 4-5, induplicate-valvate, C (3) 4-5, clawed or not; stamens (= and opposite sepals), tapetum multinucleate [Francoa]; pollen with complex endapertures; nectary intrastaminal, lobed; G [4(-5)], placentation parietal [Francoa], style short, ± impressed, stigmas sessile, commissural; ovules with bistomal micropyle, outer integument ca 2 cells across, inner integument ca 3 cells across, parietal tissue 3-6 cells across, nucellar cap ca 2 cells across, postament +, funicular obturator +; embryo sac elongated; exotestal cells elongated, exotegmic cells ± elongated, (with all walls thickened), tegmen of pigmented cells; endosperm nuclear, embryo short, radicle with anthocyanin [Francoa]; n = 20, 26.
2/2. Chile. [Photo - Francoa Habit © Gardenweek.org]
Age. The split between Francoa and Tetilla is dated at ca 4 m.y.a. (Palazzesi et al. 2012).
Evolution. Divergence & Distribution. Diversification within Vivianieae began in southern South America prior to the Andean orogeny (Palazzesi et al. 2012; Sytsma et al. 2014). Diversification within Melianthus happened some (26.2-)19.7(-12.2) m.y.a (Linder et al. 2006, q.v. for more dates, etc.), but c.f. the later dates suggested by Palazzesi et al. (2012) and Systma et al. (2014), who link diversification to the beginning of aridifiaction in South Africa.
Chemistry, Morphology, etc. Bersameae: Hutchinson (1973) described a disc lining the inside of the K. The number of nuclei in the pollen grain is unclear (Dahlgren & van Wyk 1988). For the ovules of Bersama, which face away from each other, see Danilova (1996). Khushalani (1963) described a nucellar cap 8-11 cells acros in Melianthus major, but it apparently developed from hypodermal cells and so is considered to be nucellar tissue as defined here. For general information, see Van Wyk (in Dahlgren & Van Wyk 1988) and Linder (2006), for anatomy, see Hilger (1978a, b), Gornall and Al-Shammary (1998) and Steyn for floral development, see Ronse Decraene et al. (2001b), for anthers, see Endress & Stumpf (1991), for embryogenesis, see Steyn et al. (1986), for flower and fruit, see Doweld (2001a: c.f. micropyle type), for the embryogeny of Melianthus, see Steyn (1974), and for seeds of Melianthus, see Guérin (1901) and Corner (1976).
Vivianieae: The vessel elements of Viviania sometimes have a single bar across the perforation. The inflorescence of Viviania can be replaced all or in part by a branched thorn, and the stamens are much longer than the stigma/styles. Weigend (2005) detailed some aspects of floral morphology and pollination. See Narayana and Rama Devi (1995) and Weigend (2006) for general information, Carlquist (1985b) for wood anatomy, M. S. Dunthorn (pers. comm.) for nodal anatomy of Viviania, Palazzesi et al. (2012) for pollen, Mauritzon (1933) for embryology and Boesewinkel (1997) for ovules and seeds; for carpel orientation, see Baillon (1874) and Knuth (1931). Endosperm type/development of Vivianieae is unknown.
Greyieae: The distinctive abscission of leaf plus attached cortex of the internode below as a single unit in Greyia, facilitated by the activity of the cork cambium, is described by Steyn (1974). However, Van Wyk (in Dahlgren & Van Wyk 1988) disagree with her interpretation, and show rudimentary stipules on a single plant(!) of Greyia sutherlandii. For general information, see Linder (2006), further information is taken from Bohm and Chan (1992: B-ring deoxyflavonoids), Hilger (1978a), Ramamonjiarisoa (1980) and Gregory (1998), all anatomy, Steyn and van Wyk (1987) and Ronse Decraene and Smets (1999), both floral development, Endress and Stumpf (1991: stamens), Hideux and Ferguson (1976: pollen), Steyn et al. (1986: embryogenesis), and Nemirovich-Danchenko (1995: seed coat anatomy).
Francoeae: There is a large chalazal endosperm sac in Francoa that remains free-nuclear longer than the rest of the endosperm (Gaümann 1919). For general information, see Linder (2006).
For vegetative anatomy, see Gornalll and Al-Shammary (1998), for floral morphology and development of Francoa, see Klopfer (1972a, 1973) and Ronse Decraene and Smets (1999), for embryology, see Mauritzon (1933), and for seed anatomy, see Krach (1976), Nemirovich-Danchenko (1994a) and Danilova (1996).
Phylogeny Within Vivianieae, Palazzesi et al. (2012; see also Price & Palmer 1993) found the relationships [Viviania [Rhynchotheca + Balbisia]] (Fig. 4), but support for the sister-group relationship of the latter pair of genera was not strong, and in the chronogram (Fig. 5) relationships are [Balbisia [Viviania + Rhynchotheca]] (for the latter topology, see also Systma et al. 2014). Within Bersameae, Melianthus major is probably sister to the rest of the genus (Linder et al. 2006).
Classification. Melianthaceae and Francoaceae were placed in a single family by Savolainen et al. (2000b); many of the characters given there that linked the two may be plesiomorphic. A.P.G. II (2003) suggested as an option separating Melianthaceae and Francoaceae, an option which was followed in early versions of this site; later the two were combined (see A.P.G. III 2009), while A.P.G. IV (2016) recognize the broadly-circumscribed Francoaceae above..
Previous Relationships. Greyieae were included in Sapindales by Cronquist (1981), while Francoeae have been associated with or even included in Saxifragaceae. Krach (1976) compared the testa anatomy of Francoa with that of Cunoniaceae.