EMBRYOPSIDA Pirani & Prado (crown group)
Gametophyte dominant, independent, multicellular, thalloid, with single-celled apical meristem, showing gravitropism; flavonoids + [absorbtion of UV radiation]; protoplasm dessication tolerant [plant poikilohydric]; cuticle +; cell walls with (1->4)-ß-D-glucans [xyloglucans], lignin +; rhizoids unicellular; several chloroplasts per cell; glycolate metabolism in leaf peroxisomes [glyoxysomes]; centrioles in vegetative cells 0, metaphase spindle anastral, predictive preprophase band of microtubules, phragmoplast + [cell wall deposition spreading from around the spindle fibres], plasmodesmata +; antheridia and archegonia jacketed, stalked; spermatogenous cells monoplastidic, centrioles develop de novo, associated with basal bodies of flagellae, multilayered structure +, proximal end of basal bodies lacking symmetry, stellate pattern associated with doublet tubules of transition zone; spermatozoids with a left-handed coil; male gametes with 2 lateral flagellae; oogamy; diploid embryo initially surrounded by haploid gametophytic tissue, plane of first division horizontal [with respect to long axis of archegonium/embryo sac], suspensor/foot +, cell walls with nacreous thickenings; sporophyte multicellular, sporangium +, single, with polar transport of auxin, dehiscence longitudinal; meiosis sporic, monoplastidic, microtubule organizing centre associated with plastid, cytokinesis simultaneous, preceding nuclear division, sporocytes 4-lobed, with a quadripolar microtubule system; spores in tetrads, sporopollenin in the spore wall, wall with several trilamellar layers [white-line centred layers, i.e. walls multilamellate]; spores trilete; close association between the trnLUAA and trnFGAA genes on the chloroplast genome.
Note that many of the bolded characters in the characterization above are apomorphies in the streptophyte clade along the lineage leading to the embryophytes rather than being apomorphies of the crown embryophytes.
Abscisic acid, ?D-methionine +; sporangium with seta, seta developing from basal meristem [between epibasal and hypobasal cells], sporangial columella + [developing from endothecial cells]; stomata +, anomocytic, cell lineage that produces them with symmetric divisions [perigenous]; underlying similarities in the development of conducting tissue and in rhizoids/root hairs; polar transport of auxins and class 1 KNOX genes expressed in the sporangium alone; MIKC, MI*K*C* and class 1 and 2 KNOX genes, post-transcriptional editing of chloroplast genes; gain of three group II mitochondrial introns.
[Hornworts + Polysporangiophyta]: archegonia embedded/sunken in the gametophyte; sporophyte long-lived, chlorophyllous, nutritionally largely independent of the gametophyte; sporophyte-gametophyte junction interdigitate, sporophyte cells showing rhizoid-like behaviour.
Sporophyte well developed, branched, free living, sporangia several; spore walls not multilamellate [?here]; apical meristem +.
EXTANT TRACHEOPHYTA / VASCULAR PLANTS
Photosynthetic red light response; water content of protoplasm relatively stable [plant homoiohydric]; control of leaf hydration passive; (condensed or nonhydrolyzable tannins/proanthocyanidins +); vascular tissue +, sieve cells + [nucleus degenerating], tracheids +, in both protoxylem and metaxylem; endodermis +; root xylem exarch [development centripetal]; stem with an apical cell; branching dichotomous; leaves spirally arranged, blades with mean venation density 1.8 mm/mm2 [to 5 mm/mm2]; sporangia adaxial on the sporophyll, sporangia derived from periclinal divisions of several epidermal cells, wall multilayered [eusporangium]; columella 0; tapetum glandular; stellate pattern split between doublet and triplet regions of transition zone; placenta with single layer of transfer cells in both sporophytic and gametophytic generations, embryonic axis not straight [root lateral with respect to the longitudinal axis; plant homorhizic].[MONILOPHYTA + LIGNOPHYTA]
Branching ± monopodial; lateral roots +, endogenous, root apex multicellular, root cap +; tracheids with scalariform-bordered pits; leaves with apical/marginal growth, venation development basipetal, growth determinate; sporangia borne in pairs and grouped in terminal trusses, dehiscence longitudinal, a single slit; cells polyplastidic, microtubule organizing centres not associated with plastids, diffuse, perinuclear; male gametes multiflagellate, basal bodies staggered, blepharoplasts paired; chloroplast long single copy ca 30kb inversion [from psbM to ycf2].
Plant woody; lateral root origin from the pericycle; branching lateral, meristems axillary; cork cambium + [producing cork abaxially], vascular cambium bifacial [producing phloem abaxially and xylem adaxially].
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]; lignins derived from (some) sinapyl and particularly coniferyl alcohols [hence with p-hydroxyphenyl and guaiacyl lignin units, so no Maüle reaction]; root with xylem and phloem originating on alternate radii, vascular tissue not medullated, cork cambium deep seated; arbuscular mycorrhizae +; shoot apical meristem interface specific plasmodesmatal network; stem with vascular cylinder around central pith [eustele], phloem abaxial [ectophloic], endodermis 0, xylem endarch [development centrifugal]; 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 +; stem cork cambium superficial; branches exogenous; leaves with single trace from vascular sympodium [nodes 1:1]; stomatal pore with active opening in response to leaf hydration, control by abscisic acid, metabolic regulation of water use efficiency, etc.; leaves with petiole and lamina, development basipetal, blade simple; axillary buds +, (not associated with all leaves); prophylls two, lateral; plant heterosporous, sporangia borne on sporophylls; microsporophylls aggregated in indeterminate cones/strobili; true pollen +, grains mono[ana]sulcate, exine and intine homogeneous; ovules unitegmic, parietal tissue 2+ cells across, megaspore tetrad linear, functional megaspore single, chalazal, lacking sporopollenin, megasporangium indehiscent; pollen grains landing on ovule; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, gametes two, developing after pollination, with cell walls; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large" [ca 8 mm3], but not much bigger than ovule, with morphological dormancy; embryo cellular ab initio, endoscopic, plane of first cleavage of zygote transverse, suspensor +, short-minute, embryonic axis straight [shoot and root at opposite ends; plant allorhizic], white, cotyledons 2; plastid transmission maternal; ycf2 gene in inverted repeat, whole nuclear genome duplication [zeta duplication], two copies of LEAFY gene, PHY gene duplications [three - [BP [A/N + C/O]] - copies], nrDNA with 5.8S and 5S rDNA in separate clusters; mitochondrial nad1 intron 2 and coxIIi3 intron and trans-spliced introns present.
Lignans, O-methyl flavonols, dihydroflavonols, triterpenoid oleanane, apigenin and/or luteolin scattered, [cyanogenesis in ANITA grade?], S [syringyl] lignin units common [positive Maüle reaction - syringyl:guaiacyl ratio more than 2-2.5:1], and hemicelluloses as xyloglucans; root apical meristem intermediate-open; root vascular tissue oligarch [di- to pentarch], lateral roots arise opposite or immediately to the side of [when diarch] xylem poles; origin of epidermis with no clear pattern [probably from inner layer of root cap], trichoblasts [differentiated root hair-forming cells] 0, exodermis +; shoot apex with tunica-corpus construction, tunica 2-layered; reaction wood ?, associated gelatinous fibres [g-fibres] with innermost layer of secondary cell wall rich in cellulose and poor in lignin; starch grains simple; primary cell wall mostly with pectic polysaccharides, poor in mannans; tracheid:tracheid [end wall] plates with scalariform pitting, wood parenchyma +; sieve tubes enucleate, sieve plate with pores (0.1-)0.5-10< µm across, cytoplasm with P-proteins, cytoplasm not occluding pores of sieve plate, companion cell and sieve tube from same mother cell; sugar transport in phloem passive; nodes 1:?; stomata brachyparacytic [ends of subsidiary cells level with ends of pore], outer stomatal ledges producing vestibule, reduction in stomatal conductance to increasing CO2 concentration; lamina formed from the primordial leaf apex, margins toothed, development of venation acropetal, overall growth ± diffuse, venation hierarchical-reticulate, secondary veins pinnate, veins (1.7-)4.1(-5.7) mm/mm2, endings free; most/all leaves with axillary buds; flowers perfect, pedicellate, ± haplomorphic, parts spiral [esp. the A], free, numbers unstable, development in general centripetal; P +, 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], ± embedded in the filament, with at least outer secondary parietal cells dividing, each theca dehiscing longitudinally, endothecium +, endothecial cells elongated at right angles to long axis of anther; (tapetum glandular), cells binucleate; microspore mother cells in a block, microsporogenesis successive, walls developing by centripetal furrowing; pollen subspherical, tectum continuous or microperforate, ektexine columellate, endexine thin, compact, lamellate only in the apertural regions; nectary 0; carpels present, superior, free, several, ascidiate, with postgenital occlusion by secretion, stylulus short, hollow, cavity not lined by distinct epidermal layer, stigma ± decurrent, carinal, dry [not secretory]; ovules few [?1]/carpel, marginal, anatropous, bitegmic, micropyle endostomal, outer integument 2-3 cells across, often largely subdermal in origin, inner integument 2-3 cells across, often dermal in origin, parietal tissue 1-3 cells across [crassinucellate], nucellar cap?; megasporocyte single, hypodermal, functional megaspore lacking cuticle; female gametophyte four-celled [one module, nucleus of egg cell sister to one of the polar nuclei]; supra-stylar extra-gynoecial compitum +; ovule not increasing in size between pollination and fertilization; pollen grains landing on stigma, bicellular at dispersal, mature male gametophyte tricellular, germinating in less than 3 hours, pollination siphonogamous, tube elongated, 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, flagellae 0, double fertilization +, ovules aborting unless fertilized; P deciduous in fruit; seed exotestal, becoming much larger than ovule at time of fertilization; endosperm diploid, cellular, heteropolar [micropylar and chalazal domains develop differently, 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; embryogenesis cellular; dark reversal Pfr -> Pr; Arabidopsis-type telomeres [(TTTAGGG)n]; 2C genome size 1-8.2 pg [1 pg = 109 base pairs], whole nuclear genome duplication [epsilon duplication]; protoplasm dessication tolerant [plant poikilohydric]; ndhB gene 21 codons enlarged at the 5' end, single copy of LEAFY and RPB2 gene, knox genes extensively duplicated [A1-A4], AP1/FUL gene, paleo AP3 and PI genes [paralogous B-class genes] +, with "DEAER" motif, SEP3/LOFSEP and three copies of the PHY gene, [PHYB [PHYA + PHYC]].
[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]]]]: vessel elements with scalariform perforation plates in primary xylem; essential oils in specialized cells [lamina and P ± pellucid-punctate]; tension wood +; tectum reticulate; anther wall with outer secondary parietal cell layer dividing; carpels plicate; 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 [possible position]; pollen tube growth intra-gynoecial; 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.]; (vessels with simple perforation plates in primary xylem); nodes 3:3; stomata anomocytic; flowers (dimerous), cyclic; K/outer P members with three traces, ("C" +, with a single trace); A few, (polyandry widespread, initial primordia 5, 10, or ring, ± centrifugal), 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 place]; micropyle?; 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, compitum +, placentation axile, style +, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; RNase-based gametophytic incompatibility system present; floral nectaries with CRABSCLAW expression.
[SANTALALES [BERBERIDOPSIDALES [CARYOPHYLLALES + ASTERIDS]]] / ASTERIDS ET AL. / SUPERASTERIDS: ?
[BERBERIDOPSIDALES [CARYOPHYLLALES + ASTERIDS]]: ?
[CARYOPHYLLALES + ASTERIDS]: seed exotestal; embryo long.
ASTERIDS / Sympetalae redux? / ASTERIDAE / ASTERANAE Takhtajan: nicotinic acid metabolised to its arabinosides; (iridoids +); tension wood decidedly uncommon; C enclosing A and G in bud, (connate, if evident only early in development and then petals often appearing to be free); anthers dorsifixed?; (nectary gynoecial); style +, long; ovules unitegmic, integument thick, endothelium +, nucellar epidermis does not persist; exotestal cells lignified, esp. on anticlinal and/or inner periclinal walls; endosperm cellular.
[ERICALES [ASTERID I + ASTERID II]]: (ovules lacking parietal tissue) [tenuinucellate].
[ASTERID I + ASTERID II] / CORE ASTERIDS: ellagic acid 0, non-hydrolysable tannins not common; sugar transport in phloem active; inflorescence basically cymose; A = and opposite sepals or P, (numerous, usu. associated with increased numbers of C or G); style short[?]; duplication of the PI gene.
ASTERID II / CAMPANULIDAE: myricetin 0; vessel elements with scalariform perforation plates; endosperm copious, embryo short/very short.
[ASTERALES [ESCALLONIALES [BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]]] / APIIDAE: iridoids +; C forming a distinct tube, tube initiation early; A epipetalous; ovary inferior, [2-3], style long[?].
[ESCALLONIALES [BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]]: ?
[BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]: ?
[APIALES [PARACRYPHIALES + DIPSACALES]] / DIPSAPIIDAE: nodes 3:3.
[PARACRYPHIALES + DIPSACALES] / DIPSIDAE: true tracheids +; lamina serrate; inflorescence terminal.
Age. K. Bremer et al. (2004) suggested an age of about 111 m.y. for this node.
Evolution. Divergence & Distribution. Diversification at this node probably occurred in the southern hemisphere (Beaulieu et al. 2013a).
Dipsacales, with some 1130 species, are far more diverse than Paracryphiales - the latter include a mere 36 or so species.
Phylogeny. For the placement of Paracryphiaceae/Paracryphiales, see Winkworth et al. (2008a) and especially Tank and Donoghue (2010); support for the position here was only slight in the full analysis of Soltis et al. (2011).
PARACRYPHIALES Reveal Main Tree.
Inflorescence racemose; flowers 4-merous; P or K + C free; A not adnate to P/C, anther thecae ± embedded in connective; G position?; capsule septicidal. - 1 family, 3 genera, 36 species.
Age. K. Bremer et al. (2004) suggested an age of about 101 m.y. for crown-group Paracryphiaceae/Paracryphiales; for more details, see below.
Note: Possible apomorphies are in bold. However, the actual level at which many of these features, particularly the more cryptic ones, should be assigned is unclear. This is partly because many characters show considerable homoplasy, in addition, basic information for all too many 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 is the not-so-trivial issue of how ancestral states are reconstructed...
Chemistry, Morphology, etc. The three genera included in Paracryphiales are quite different florally and are rather unlike other asterid II taxa, however, they are poorly known for the most part and need an exhaustive comparative study. Quintinia is reported to have ellagic acid (along with iridoids!), and it and fossils that have been associated with it may even have bitegmic ovules (Friis & Pedersen 2012). Sphenostemon and Paracryphia sometimes have more than twice as many stamens as perianth parts; the apomorphies of Paracryphia in particular represent a very odd combination for a member of the [asterid I + asterid II] clade. For more on the inferior/superior ovary distinction in the asterid II clade, see the Asterales page. Altogether, something of a conundrum.
Phylogeny. Paracryphia was linked quite strongly with Rutaceae + Meliaceae + Simaroubaceae by Källersjö et al. (1998), but c.f. Savolainen et al. (2000a). In a 17-gene analysis by Soltis et al. (2011), Quintinia linked with Polyosma (Escalloniales here), but support for this position came from the mitochondrial component of the analysis; Soltis et al. (2011) were inclined to think that horizontal gene transfer of the mitochondrial genes might be involved. Paracryphiaceae form a clade in Lundberg's three-gene Bayesian analysis (Lundberg 2001e); Cameron (2001, 2003) also suggested an association between Paracryphia and Sphenostemon. The clade has strong support in Tank and Donoghue (2009). For the positions of the other smaller clades along the asterid II spine, which are now mostly settling down, see Escalloniales.
Synonymy: Sphenostemonineae I. Savin. - Quintiniales Doweld, Sphenostemonales Doweld
PARACRYPHIACEAE Airy-Shaw Back to Paracryphiales
Trees or shrubs, evergreen; leaves spiral; inflorescence racemose.
3 [list]/36. Southwest Pacific: Philippines to New Zealand and New Caledonia.
Age. K. Bremer et al. (2004) suggested an age of about 101 m.y. for crown-group Paracryphiaceae.
The Late Cretaceous Silvianthemum suecicum, from rocks in southern Sweden ca 83.5 m.y.o., has several exquisitely-preserved features - perhaps most notably the radial stylar cells - suggesting a relationship with Quintinia in particular (Friis 1990; see also Martínez-Millán 2010; Friis et al. 2011, 2013b). However, it has tricolp(or)ate pollen, there are eight stamens (but the perianth is 5-merous), the anthers appear to be dorsifixed, and there are three short, adaxially grooved styles (c.f. Quintinia). Bertilanthus scanicus, from the same rocks, has a very similar set of characters, and, like Quintinia, it has glandular hairs, but it also has stamens opposite the petals, a feature at most vanishingly infrequent in the asterid II clade, and differs in other respects from Quintinia (Friis & Pedersen 2012). However, the androecium in extant Paracryphiales is variable. The ovules of Bertilanthus may be bitegmic ("ovary wall [sic] split in two": Friis & Pedersen 2012: p. 326), which would be in line with reports for Quintinia.
If the relationships of these fossils hold, then the current distribution of Paracryphiales has little to do with their past distribution. However, a position of the fossils within Cornales was suggested by Beaulieu et al. (2013a), which agrees better with their morphology (and geography). On the other hand, Friis et al. (2013b) are inclined to question the position of Quintinia, too, in the asterid II clade.
1. Quintinia A. de Candolle
Plants Al accumulators, group 1 secoiridoids, ellagic acid +; vessels vestured; petiole bundle?; peltate glands +; buds naked; (lamina margins entire); inflorescences axillary, unbranched; flowers also 5-merous; K with 1 trace, aestivation open, not protecting bud; anthers ± basifixed; pollen 4-6 colporate; G [3-5], inferior, placentation ± parietal, nectary on top of ovary, style longish, postgenitally connate, stout, with prominent radiating cells, stigmas expanded, wet; ovules 3-many/carpel, bitegmic, micropyle endostomal, parietal tissue 2-3 cells across; K persistent; micropylar endosperm haustorium?; n = ?22.
1/25. Philippines and New Guinea to New Zealand and New Caledonia (map: from Heywood 2007, in part).
Synonymy: Quintiniaceae Doweld
[Paracryphia + Sphenostemon]: styloids +; hairs unicellular; bud perulate; inflorescence terminal; P +; nectary 0; style 0.
2. Paracryphia Baker f.
Chemistry?; three traces entering the base of the petiole; petiole bundle flattened-annular, with medullary bundles; (leaves entire); plant andromonoecious; inflorescence branched; flowers sessile; (P 5), decussate-cochleate, caducous; A 8(-11); G [8-15], stigmas central, separate, conduplicate; ovules 4/carpel, crassinucellate; carpels pulling away acropetally and opening adaxially, columella persistent; seeds winged, exotesta? with sinuous anticlinal walls, inner walls lignified; embryo size?, radicle relatively long; n = ?
1/1: Paracryphia alticola. New Caledonia.
3. Sphenostemon Baillon
Iridoids?; phloem stratified; petiole bundles three, arcuate, or annular with wing bundles; (styloids 0); leaves (opposite), (lamina margins entire), stipules cauline, minute; inflorescences unbranched; (P 2), decussate; stamens = and opposite P-12, connective/filament massive; pollen por(or)ate; G , placentation apical, stigma large, capitate; ovules 1(2)/carpel, funicular obturator +, endothelium?; fruit a berry; seeds ruminate or not, exo- or exoendotestal, endotestal cells with dark contents; embryo short?; n = ?
1/10. New Guinea, Australia (Queensland) and New Caledonia (map: from van Balgooy 1984; Mark Newman, pers. comm.).
Synonymy: Sphenostemonaceae P. van Royen
Chemistry, Morphology, etc. The vessel elements of the three genera are very long and the perforation plates have many bars, indeed, aspects of the wood anatomy of Paracryphia have even been considered to be among the most primitive in angiosperms. Styloids are visible on the abaxial surface of the lamina of Papuasian species of Sphenostemon; they look rather like cystoliths.
Quintinia is almost unknown embryologically. Its placentation is basically parietal (Bensel & Palser 1975b; see also Friis et al. 2103b); the ovules are bitegmic and crassinucellate (Mauritzon 1933; Philipson 1974; Friis et al. 2013b). For some details of the flower of Sphenostemon, see Endress (2008c). The fruit is often described as being a drupe, but Lundberg (2001c) characterized it as being a pseudo-drupe (and the seeds as being pachychalazal), while Savinov (2003) described it as being a berry. The nature of the perianth in both Paracryphia and Sphenostemon needs attention. In the former, it is almost as if the bract encloses the sessile flower, while in the latter the first perianth members are lateral and subpeltate.
For Paracryphia, see also Dickison and Baas (1977) and Carlquist (2012c) for wood anatomy, and Lundberg (2001e: general); for Quintinia, see Lundberg (2000d: general); and for Sphenostemon, see Jéremie (1997) for general information, Carlquist (2012c) for wood anatomy, and Savinov (2003) for fruit and seed anatomy.
Sphenostemon is particularly poorly known.
Phylogeny. Relationships are [Quintinia [Paracryphia + Sphenostemon]] (Tank & Donoghue 2009).
Classification. The three genera have all been placed in monogeneric families, but only relatively recently; they are combined here (see also A.P.G. 2009).
Thanks. Thanks to Y. Pillon for comments.
Previous Relationships. Paracryphiaceae were included in Theales by Cronquist (1981) and in Theanae by Takhtajan (1997). Quintinia has long been included in woody Saxifragaceae/Hydrangeaceae. Baas (1975) thought that Sphenostomonaceae (and Phellinaceae) were members of Celastrales, close to Icacinaceae; Cronquist (1981) had placed them in Aquifoliaceae, next to Icacinaceae, while Takhtajan (1997) included them in Icacinales. Sphenostemon (as Idenburgia) has also been placed in Trimeniaceae.