EXTANT SEED PLANTS

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

MAGNOLIOPHYTA

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

Evolution. Possible apomorphies for flowering plants are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied, there is considerable variation between families in particular for several of these characters, and also because details of relationships among gymnosperms will affect the level at which some of these characters are pegged. For example, if reticulate-perforate pollen is optimized to the next node on the tree (see Friis et al. 2009 for a discussion), it effectively makes the pollen morphology of the common ancestor of all angiosperms ambiguous....

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

ERICALES [ASTERID I + II]: ovules tenuinucellate.

ASTERID I + II: Ellagic acid 0, proanthocyanidins not common; inflorescence cymose; C forming a distinct tube; A epipetalous, = and opposite sepals or P [polyandry (secondary) very uncommon indeed].

ASTERID II: myricetin 0; vessel elements with scalariform perforation plates; style short; flowers rather small, style short; endosperm copious, embryo short/very short.

ASTERALES [ESCALLONIALES [BRUNIALES [APIALES [PARACRYPHIALES + DIPSACALES]]]]: iridoids +; C tube initiation early; G [2-3], inferior.   Back to Main Tree

Previous Relationships. Various families have been placed here or elsewhere in the asterid II clade, but with uncertain support; recent work is clarifying their relationships (Winkworth et al. 2008a; Tank & Donoghue 2009). For Polyosmaceae and Escalloniaceae, see below; Paracryphiaceae, Quintiniaceae, and Sphenostemonaceae are combined as Paracryphiaceae and form a clade sister to Dipsacales; while Columelliaceae and Desfontainiaceae (as Columelliaceae) are close Bruniaceae, together making up Bruniales.

APIALES Nakai  Main Tree, Synapomorphies.

Woody; route II decarboxylated iridoids +; vessels solitary; pits [both vessels and fibres] bordered; ?stomata; leaves pinnatinerved (margins toothed or lobed); inflorescence terminal, paniculate; plants dioecious; pedicels articulated; flowers small, K small, C apparently free; A free from C; G [3], abaxial carpel fertile [?Pennantia], 1-2 apical apotropous ovules/carpel, nucellus type?, funicular obturator +; fruit a single-seeded drupe; endosperm nuclear; x = 6?; mitochondrial rpl2 gene lost. - 7 families, 494 genera, 5489 species.

Evolution. Apiales contain ca 2.4% eudicot diversity (Magallón et al. 1999). Wikström et al. (2001) suggest a Santonian-Turonian age for the clade of some 90-85 million years before present, with divergence in the Apiaceae-Araliaceae area occuring 48-46 million years before present, although details of relationships within the clade differ from those given here. Janssens et al. (2009) date stem group Apiales to 104±11.2 million years ago and the crown group to 87±14.1 million years.

Chemistry, Morphology, etc. The basal pectinations are genera which used to be in Cornales/Cornanae - and they have transseptal bundles in common, as well as clustered vessels, septate fibers with simple pits, some rays over 10 cells wide and with square or upright cells (Noshiro & Baas 1998; Baas et al. 2000) - as well as the even more different Pennantia, late of Icacinaceae. Unfortunately, corolla initiation, pollen nucleus number, and many other characters are unknown for these taxa, although some information for the ex-Cornalean genera can be found in Patel (1973), Philipson (1967), and Philipson and Stone (1980). Griseliniaceae and Torricelliaceae both have griselinoside, transseptal bundles in the ovary, and the abaxial carpel alone is fertile, the single ovule being apotropous. Pennantia, sister to all other Apiales, has a superior ovary (and sometimes a thick, disciform, sessile stigma)... In particular, how the gynoecium of Pennantia is interpreted (summarized in Kårehed 2003a) has many implications for character evolution. Here it is interpreted as being tricarpellate, although it appears to be only a single carpel, and it is assumed that the abaxial carpel is fertile (see also Chandler & Plunkett 2004; Plunkett et al. 2004c for carpel number).

Further complicating the issue, the outgroup to Apiales is Bruniales, a small but heterogeneous clade, and so character evolution in the basal part of Apiales in particular is very uncertain. Thus of taxa close to Apiales, Sphenostemon (Paracryphiaceae, Paracryphiales), has a superior ovary, in Adoxaceae, sister to other Dipsacales, the ovary is only semi-inferior (and in Tetradoxa the ovary was described as being superior - Ying et al. 1993), and in Bruniales the ovary varies from superior to inferior. Understanding perforation plate variation in a phylogenetic context is similarly problematic.

Kårehed (2003, for which see for further details, also Chandler & Plunkett 2004) provides a good summary of what is known of the main clades in Apiales, although as just mentioned optimising character state change on the tree is not simple, even given its current constitution. For wood anatomy, see Lens et al. (2008a). Endress (2003c) summarizes the literature on nucellus development in the clade; there are a number of glaring gaps in our knowledge. Yi et al. (2004) suggest that the basic chromosome number in Apiales is x = 6 (see also Raven 1975), although the order then would have all polyploid/dysploid members, with several independent origins of polyploidy.

Phylogeny. Within Apiales, the grouping (Griselinia (Aralidium + Torricellia)) is rather weakly supported, mainly in earlier studies (Backlund & Bremer 1997; see also Chandler & Plunkett 2002). The ex-Icacinaceae Pennantia is sister to other Apiales (Kårehed 2003; Lens et al. 2008a). Plunkett (2001) and Lundberg (2001c) both suggest that Torricelliaceae and Griseliniaceae are successive clades near the base of Apiales, and this has strong Bayesian support (Kårehed 2002a: four genes, all genera sampled), and this topology is followed here (note that the relationship is reversed in, but with a p.p. of 0.93). Chandler and Plunkett (2004) and especially Tank et al. (2009) are resolving relationships both within Apiales and between Apiales and their immediate relatives (see also tree). Some Bayesian analyses yield strong posterior probabilities for a relationship between Myodocarpaceae and Pittosporaceae (Chandler & Plunkett 2004), but on balance the relationships [Pittosporaceae [Araliaceae [Myodocarpaceae + Apiaceae]]] seem most likely (Tank et al. 2009).

Previous Relationships. Apiales include Pennantia, late of Icacinaceae. Of other taxa placed here, Melanophylla was included in Hydrangeales and Torricellia, Griselinia and Aralidium in separate monogeneric orders, all in Cornidae-Cornanae, by Takhtajan (1997); all have been placed in Cornaceae s.l.

There are some similarities between [Pittosporaceae [Araliaceae [Myodocarpaceae + Apiaceae]]] and some Asterales (esp. Campanulaceae s.l. and Asteraceae) (e.g. Erbar & Leins 2004; Leins & Erbar 2004b). However, given the rather strongly supported set of relationships at the base of Apiales, the other clades that are in this part of the asterid II phylogeny, and relationships within Asterales (Campanulaceae s.l. and Asteraceae are not immediately related), most of these similarities will probably be plesiomorphies or more likely parallelisms (see also below).

Includes Apiaceae, Araliaceae, Griseliniaceae, Myodocarpaceae, Pennantiaceae, Pittosporaceae, Torricelliaceae.

Synonymy: Apiineae Plunkett & Lowry, Aralidiinae Thorne & Reveal - Ammiales Small, Araliales Reveal, Aralidiales Reveal, Griseliniales Reveal & Doweld, Hederales Link, Pennantiales Doweld, Pittosporales Lindley, Torricelliales Reveal & Doweld - Aralianae Takhtajan

PENNANTIACEAE J. Agardh   Back to Apiales

Trees or shrubs; iridoids ?; diffuse apotracheal parenchyma +/0; nodes 3:3; petiole bundle annular (with a medullary bundle) and with solid wing bundles; stomata paracytic; hairs uniseriate; leaf margins also entire; K free, C connate, valvate, apex inflexed, disc/nectary 0; staminate flowers: A dorsifixed (epipetalous), pistillode +; carpellate flowers: staminodes +/0; G also [2], nucellus?, styles short, stigmas punctate, or stigma sessile, broad; drupe with inner cells transversely elongated; seed coat thin; endosperm development?, embryo short/minute [to 1/3 the seed length]; n = 25.

1/4. N.E. Australia, Norfolk Island, New Zealand (map: from van Balgooy 1966; George 1984). [Photo - Habit.]

Chemistry, Morphology, etc. Collenchyma is only poorly developed, and a pericyclic sheath is present; pits in general are bordered. For the morphology of the stigma, see Kårehed (2002b).

For other information, both about Pennantiaceae and about other members of the old Icacinaceae (here in Garryales and Aquifoliales), see Miers (1852: ovule orientation), Bailey and Howard (1941: anatomy); see also Fagerlind (1945: embryology), Heintzelmann and Howard (1948), Padmanabhan (1961: embryology), Sleumer (1971a: general), van Staveren and Baas (1973: epidermis), Baas (1973: epidermis, 1974: stomata), Lobreau-Callen (1980: pollen), Kaplan et al. (1991: chemistry), Teo and Haron (1999: anatomy), Kårehed (2001, 2002b, 2003: the taxa in their current circumscription), and Lens et al. (2008a: wood anatomy). Gardner and de Lange (2002) monographed Pennantia, providing a number of interesting morphological and anatomical details.

Torricelliaceae [Griseliniaceae [Pittosporaceae [Araliaceae [Myodocarpaceae + Apiaceae]]]]: young stems with peripheral collechyma; vessels mainly in groups; vessel element perforations simple; pits in general with at most narrow borders; paratracheal parenchyma +, scanty; pericyclic fibers 0 or few; nodes 5(+):5(+); leaf bases broad; C apparently free, imbricate, styles/stigmas recurved.

Chemistry, Morphology, etc. For the wood anatomy of this clade, see Lens et al. (2008a).

TORRICELLIACEAE H. H. Hu   Back to Apiales

Trees; griselinoside, ellagic acid +, tanniniferous [Torricellia]; (vessel elements with scalariform perforation plates - Aralidium); petiole bundles scattered [Aralidium]; crystal sand +; mucilage cells +; stomata anomocytic (anisocytic); glandular hairs +; leaf margins lobed and toothed or toothed, (2ndary veins ± palmate), petiole margin with basal (+ small adaxial) flange, encircling stem or not; K medium, imbricate or largely connate, staminate flowers: (C induplicate-valvate - Torricellia), pollen tectum reticulate; carpellate flowers: (C 0 - Torricellia); G [(2-4)], (disc vascularised - Aralidium), transseptal bundles +, integument massive [Aralidium], (stigmas ± bifid - Torricellia); fruit with two large empty loculi and one smaller fertile loculus [?Melanophylla], endocarp with sclereids; seed ± curved, (ruminate, coat vascularised [Aralidium]), exotesta scalariform-thickened, unlignified [Melanophylla], testa slightly sclerified [Torricellia]; (embryo long, thin - Torricellia); n = 12, 20 ± 2.

3[list]/10. Madagascar, South East Asia and W. Malesia (map: fossils [blue] from Meller 2006). [Photo: Melanophylla Habit, Flower.]

Evolution. For the fossil history of the East Asian endemic Torricellia, see Meller (2006) and Manchester et al. (2009); the genus was widespread in the northern hemisphere in the Eocene.

Chemistry, Morphology, etc. For fruit and seed of Melanophylla, see Trifonova (1998), for the circumscription of this clade, see also Plunkett et al. (2004). Other information is taken from from Philipson (1977), Philipson and Stone (1980), and Takhtajan (2000).

Classification. For a revision of Melanophylla, see Schatz et al. (1998).

Synonymy: Aralidiaceae Philipson & B. C. Stone, Melanophyllaceae Airy Shaw

Griseliniaceae [Pittosporaceae [Araliaceae [Myodocarpaceae + Apiaceae]]]: petroselenic acid + [in seed: CH₃-[CH₂]₁₀-CH=CH-[CH₂]₄-COOH]; hairs rarely glandular; petals 1-veined, nectary of sorts +, endothelium +.

GRISELINIACEAE A. Cunningham   Back to Apiales

Trees or shrubs (climbing); griselinoside +, tannins 0; vessels single, vessel element perforations scalariform; pits in general with distinct borders; diffuse-in-aggregates axial parenchyma +, scanty; petiole bundles (incurved) arcuate; mucilage cells +; stomata cyclocytic; hairs unicellular; leaves two-ranked, conduplicate, margins toothed or entire, bases with petiole margin + adaxial flange, encircling stem, or not; K open; staminate flowers: A dorsifixed, pollen tectum striate, carpellate flowers: (C 0); G [(4)], disc +, transseptal bundles +, (2 carpels fertile), ovule crassinucellate [weakly so]; fruit baccate; testa ?many layered, outer two (and esp, third) layers with thickened walls; embryo long; n = 18.

1[list]/6. New Zealand and S. South America (map: from Dillon & Muñoz-Schick 1993). [Photo: Inflorescence, Leaves, Habit, Flower (scroll to end).]

Chemistry, Morphology, etc. For seed fatty acids, see Badami and Patil (1981), in part. The wood has solitary vessels and apotracheal parenchyma (Baas et al. 2000). Takhtajan (2000) provides details of embryo and testa. For leaf insertion, cf. Philipson (1967), and for leaf base, cf. Takhtajan (1997). For Griselinia flowers, see Eyde (1964). Further information is taken from Philipson (1977) and Dillon and Muñoz-Schick (1993).

Previous Relationships. Eyde (1964) suggested a relationship between Griselinia and Garrya (Garryales) and Cornaceae (Cornales).

Pittosporaceae [Araliaceae [Myodocarpaceae + Apiaceae]]: plant often aromatic, ethereal oils, polyacetylenes [mainly aliphatic, the C₁₇ acetylenes, falcarinone, etc.], acetate-derived anthroquinones, coumarins +, iridoids, flavonols, tannins 0; lateral roots originating from either side of the xylem poles; schizogenous secretory canals in pericycle; (nodes 3:3); petiole bundles arcuate or annular; leaves conduplicate; flowers perfect and imperfect [plant andromonoecious or dioecious]; C tube formation early, pollen trinucleate; G [2], both fertile, stigma wet; hemicellulosic seed reserves common [?right place]; x = 12.

Evolution. Which groups are food plants for butterfly larvae may be of interest. Ehrlich and Raven (1964) note that some butterflies that do not seem to like Araliaceae, including Hydrocotyle, are found on Apiaceae (?including Saniculoideae); thus the Papilio machaon group is not found on Araliaceae because that family lacks the furanocoumarins that the caterpillars like (Berenbaum 1983).

It is likely that many of the apparently plesiomorphous characters of Pittosporaceae, e.g. 'normal'-looking entire leaf blade and petiole with rather narrow insertion, superior ovary, etc., are derived. (Note that the leaves of seedlings of Pittosporum may be pinnatifid.)

Chemistry, Morphology, etc. Triterpenoid ethereal oils produce the distinctive odour characteristic of many of these plants; see Jay (1969) for suggestions based on plant chemistry that members of this group are related. Lateral roots originate from either side of the xylem poles because a resin canal runs down the stem at the apex of the pole (Van Tieghem & Douliot 1888).

Note that there are a number of characters that may be of systematic interest and delimit clades of various sizes here. These include the presence of sesquiterpene lactones and benzylisoquinoline alkaloids; inverted vascular bundles in the pith and/or cortex; presence of crystal sand; palisade mesophyll often with arm cells; exotestal cells tangentially elongated, tanniniferous. As to other characters, the vessel:ray pits are bordered (Baas et al. 2000). Members of both Araliaceae s. str. and Apiaceae s. str. in clades that are sister to the rest of these families have simple leaves, as have Myodocarpaceae (Plunkett 2001) and of course Pittosporaceae, so compound leaves may have evolved independently in Apiaceae and Araliaceae. Leaf teeth have a broad glandular apex with a main and two accessory veins, or one vein proceeds above the tooth; a survey of tooth morphology might be interesting.

For information on ventral carpel bundles, see Philipson (1970) and Eyde and Tseng (1971); when the united ventral bundles are opposite the carpels, the two bundles come from the same carpel, and when they are in the septal radii, the two bundles are derived from adjacent carpels. For ovule morphology, see Jurica (1922) and van Tieghem (1898). According to the latter, Apiaceae have a thick integument (e.g. ca 7 cells - Gupta 1970), that of Hedera is very thick, although Philipson (1977) described the integument of Araliaceae as being "thin". A synthesis of what is known about ovule number and type would be useful (but see Philipson 1970 for ovule number). Note that there is not only variation in what kinds of calcium oxalate crystals are found in the fruit wall, i.e., single rhomboidal crystals or druses, but also where they occur, e.g. in the endocarp or mesocarp, all around the fruit or only in commissural area (Liu et al. 2006); I have only just begun to work out the phylogenetic significance of the later variation (see also Rompel 1895; Burtt 1991a). Kleiman and Spencer (1982) surveyed Apiaceae and Araliaceae for the occurence of petroselenic acid.

Some Pittosporaceae and a few Araliaceae have basally connate petals (Plunkett 2001). Erbar and Leins (1988, 1996a, 2004) suggested that the nectary "disc" of Apiaceae and Araliaceae is a carpellary flank nectary displaced by intercalary growth, and that the axile placentation of these two families is easily related to the parietal placentation of Pittosporaceae. In Pittosporaceae there was a short basal zone with separate loculi, the ovules being borne above this zone - essentially the same position in which the ovules of Apiaceae and Araliaceae are found. However, gynoecial development, etc., in the whole Apiales needs reinvestigation, given the inclusion of the superior-ovaried Pennantiaceae as sister to the rest of the order - and taxa with more or less superior ovaries are scattered throughout the asterid II clade. Indeed, the floral morphology of Pittosporaceae is quite probably derived, rather than representing the plesiomorphic condition from which the distinctive flowers of [Apiaceae + Araliaceae] evolved.

For variation in the sequence of initiation of parts of the flower, see Erbar and Leins (1985: mostly Apiaceae, also Hydrocotyle, the latter rather different - and lacking a calyx!), for chromosome numbers, see Yi et al. (2004), and for fruit wings and fruit anatomy, see Liu et al. (2006).

Phylogeny. Pittosporaceae may be sister taxon of the whole group (e.g. Kårehed 2002c; Andersson et al. 2006, strong support, but Myodocarpaceae not included), and this position was found to be strongly supported by Tank and Donoghue (pers. comm., D. Tank), however, some studies have found Pittosporaceae to be embedded in the group (see also Chandler & Plunkett 2004) or provided only weak support for a sister group position (Nicolas & Plunkett 2009). In any case, many of the apparently plesiomorphous characters of Pittosporaceae may be derived (see above).

Finally, there is the issue of the demise of the old woody Araliaceae/herbaceous Apiaceae distinction. Myodocarpaceae and Apiaceae-Mackinlayoideae as recognised here both include genera that used to be in Araliaceae, but the precise relationships of the former in particular have been uncertain - see Plunkett and Lowry (2001), Lowry et al. (2001), Plunkett (2001) and Chandler and Plunkett (2004) for more information. Since there are a number of morphological similarities between the Mackinlaya clade and Apiaceae s. str. (Chandler & Plunkett 2002, 2004), the former is included in the latter. Hydrocotyloideae (herbaceous and with simple leaves) were previously included in Apiaceae, but they are highly polyphyletic - Hydrocotyle is here placed in Araliaceae (and this position makes morphological sense), Arctopus is in Apiaceae-Saniculoideae, Azorella and a group of genera form a well supported clade, while Centella, Micropleura, Actinotus, etc., are in Apiaceae-Mackinlayoideae (e.g. Downie et al. 1998, Downie et al. 2000; Chandler & Plunkett 2003, 2004; Plunkett et al. 2004; Andersson et al. 2006; esp. Nicolas & Plunkett 2009). That being said, nodes along the backbone of this part of the tree have rather moderate support (Nicolas & Plunkett 2009). Very few genera remain to be sequenced, and although sampling must be improved in large genera like Hydrocotyle and Trachymene, it is unlikely to affect their positioning in Araliaceae.

For other work on phylogenetic relationships in the Apiaceae-Araliaceae area, see e.g. Judd et al. (1994: Pittosporaceae not included), Oskolski et al. (1997), Oskolski & Lowry (2000), Plunkett (1998), Plunkett et al. (1996, 1997a, 1997b), and Kårehed (2002c).

PITTOSPORACEAE R. Brown, nom. cons.   Back to Apiales

Trees or twining vines; furanocoumarins +, (hydroxycoumarins), proanthocyanins +, petroselenic acid 0, C₂₀ and C₂₂ fatty acids abundant; young stem with (± interrupted - Pittosporum) vascular cylinder; nodes 1:3, 3:3; petiole bundles arcuate; stomata paracytic; hairs uniseriate, terminal cells vertically or transversely [T-shaped hair] elongated or glandular; leaf ptyxis supervolute-curved, margins entire, 2ndary veins pinnate, base narrow to sheathing, stipules 0; flowers medium-sized; K large, free (± connate), C often slightly basally connate, 3-5-veined, anthers ± basifixed, placentoid +; G [(3-5)], flank nectaries +, many (incompletely tenuinucellate; apotropous) ovules/carpel, endothelium 0, funicular obturator 0?, style +, straight, stigma capitate (lobed); fruit a loculicidal (+ septicidal) capsule or berry, K deciduous; seeds often with sticky pulp, testa many layered, exotestal cells thickened, unlignified.

6-9[list]/200: Pittosporum (140). Old World, especially Australia, tropical and warm temperate, outside the immediate Australian region, mainly Pittosporum (map: from van Steenis & van Balgooy 1966; Good 1974; Palgrave 2002). [Photo - Flower]

• Pittosporaceae are aromatic woody and sometimes thorny plants with simple, estipulate leaves and rather conspicuous flowers that have sepals, petals and stamens equal in number and a bicarpellate gynoecium with parietal placentation. The fruits are often capsular and enclose pulpy-resinous seeds; the calyx is deciduous.

Chemistry, Morphology, etc. Glucosinolates are reported from Bursaria spinosa, but this is probably a mistake (Fahey et al. 2001). In Pittosporum, at least, the flowers are often functionally unisexual. There is a tendency, especially evident in taxa like Cheiranthera, for the flowers to be obliquely monosymmetrical; asymmetry is largely because of the position of the stamens and gynoecium. Seedlings of Pittosporum have up to five cotyledons.

For endothelium, see Batygina et al. (1985), for seed oils (undistinguished), Stuhlfauth et al. (1985), for vegetative anatomy, Wilkinson (1992, 1998), and for testa anatomy, see Takhtajan (2000: the ovules may be apotropous).

Phylogeny. Cayzer (references in Chandler et al. 2007) has carried out a number of morphological revisions and phylogenetic analyses of parts of Pittosporaceae; changes in taxon limits that she suggests are largely confirmed by a preliminary molecular study (Chandler et al., in Plunkett et al. 2004c). However, generic limits in the Billardiera-Sollya area are still unclear (Chandler et al. 2007). For relationships between species of Pittosporum found in the Pacific, see Gemmill et al. (2002).

Previous relationships. Pittosporaceae were included in Rosales by Cronquist (1981) and Mabberley (1997). However, evidence has been mounting for over 100 years that they were best associated with Apiaceae/Araliaceae (Hegnauer 1969b for a summary of some literature), and Takhtajan (1997) included them as a separate order in his Aralianae (along with Byblidales).

Araliaceae [Myodocarpaceae + Apiaceae]: polyacetylene C₁₈ tariric seed fatty acid +; leaves (compound), margins toothed or otherwise incised; ultimate units of inflorescences umbels; nectariferous stylopodium +, two epitropous ovules/carpel, one much reduced; fruits ± laterally flattened; hemicellulosic seed reserves common; 92 bp deletion in rpl16 gene.

Chemistry, Morphology, etc. For wood anatomy, see Oskolski (2001), and for the rpl16 deletion, see Downie et al. (2000a).

ARALIACEAE Jussieu, nom. cons.   Back to Apiales

Hydroxycoumarins +, furanocoumarins 0; stomata para- or aniso-(anomo-)cytic; hairs often stellate or dendroid; stipules cauline or petiolar, or 1 intrapetiolar, or 0; C valvate (imbricate - Aralia, Panax, etc.; A 3, many), ventral carpel bundles are fused bundles of adjacent placentaa (the same - e.g. Harmsiopanax), ovules crassinucellate to tenuinucellate, (nucellar cap +), integument "thin" [?level], (endothelium +), funicle with short hairs [cf. obturator], stigma punctate (dry); fruit drupaceous or dry, mesocarp thick-walled, lignified, (berry), with single rhomboidal crystals in cell layer immediately outside endocarp, endocarp sclerified; (seeds ruminate), exotestal cell walls a little thickened; (n = 9, 11, 18).

43/1450. Largely tropical, few temperate. Two groups below.

1. Hydrocotyloideae Link

± herbaceous; nodes 3:3; leaves rounded-peltate, margin crenate, stipules cauline; (K 0 - Hydrocotyle), funicle "short"; fruit schizocarpic, (undivided carpophore +).

4/175: Hydrocotyle (130), Trachymene (45). Tropical, including montane, also warm temperate.

Synonymy: Hydrocotylaceae N. Hylander

2. Aralioideae Eaton

Woody (herbaceous); leaves also pinnately to palmately compound; G [1-5(-200+)], when 5, opposite petals, when 3, median abaxial.

41[list - but see Plunkett et al. 2004a for genera]/1275: Schefflera (650: wildly polyphyletic), Polyscias (150: paraphyletic), Oreopanax (80), Dendropanax (70), Aralia (68), Osmoxylon (50). Largely tropical, few temperate (map: see Meusel et al. 1978; Hultén & Fries 1986; FloraBase 2006). [Photo - Flowers, Fruits.]

Synonymy: Hederaceae Giseke, Botryodendraceae J. Agardh

• Araliaceae may be recognised quite easily. They are often rather stout-stemmed and little-branched shrubs or trees, rarely herbs, with large and prominent scars from the fallen leaves; the plant may smell strongly. The leaves are often variously compound and with broad bases, although these latter rarely more or less encircle the stem; stipules are common and are morphologically diverse, although they are generally borne on the leaf base. Petioles are often long, and/or they vary considerably in length on the one shoot. The ultimate units of the inflorescence are umbels or heads, the flowers are often rather small, there are often three or more carpels and the petals are valvate; the fruit is drupaceous, sometimes flattened laterally, and the seeds may be ruminate.

Evolution. For shifts in the rate of molecular evolution within Araliaceae that are correlated with changes in habit, see Smith and Donoghue (2008).

Chemistry, Morphology, etc. Hedera may have an interrupted fibrous pericyclic sheath; creeping forms have two-ranked leaves. As to stipules - Fatsia (no stipules) x Hedera (no stipules) = X Fatshedera (stipules) - but note that some species of Hedera have a hollowed leaf base with a stipule-like margin, the whole enclosing the bud... For the anatomy of flower and fruit of Hydrocotyle and genera previously asssociated with it, see Tseng (1967); Hydrocotyle lacks a calyx, and its integument is ca 5 cells across. Both Aralioideae and Hydrocotyle show early corolla tube initiation (Leins & Erbar 1997; Erbar & Leins 2004). Osmoxylon has basally connate petals. Plerandra (= Schefflera) may have up to 25 or more carpels and to 500 stamens; flowers in Aralioideae may be up to 12-merous. When stamens are numerous they are often in a single whorl, thus Tupidanthus calyptratus has up to 172 stamens and 132 carpels; the carpels are initiated in a single elongated and sometimes contorted whorl looking rather like a brain cactus (fasciated: Oskolski et al. 2005; see also Eyde & Tseng 1971). In Plerandra there are about as many stamens as carpels, separate members of the calyx cannot be distinguished, and although the symplicate zone of the gynoecium develops first, the carpels are largely synascidiate; there is a large, flat remnant of the floral axis within the carpel whorl (Sokoloff et al. 2007b). Nuraliev et al. (2009) In Plerandra there may be up to four series of stamens (Philipson 1970). Tetraplasandra gymnocarpa and T. kavaiensis have secondarily more or less completely superior ovaries (Costello & Motley 2000, 2001, 2004 - see photograph on the cover of American J. Bot. 91(6) 2004). Hydroctyle, almost alone in the family, is highly polploid (Yi et al. 2004).

For general information, see Philipson (1970), for wood anatomy, see Oskolski (1996), for pollen of Chinese Hydrocotyle, see Shu and She (2001).

Phylogeny. Basal Araliaceae may well be bicarpellate (see also Wen et al. 2001) and have simple leaves. Both these are features of the herbaceous Hydrocotyloideae (ex Apiaceae), which are sister to the rest of the family (Chandler & Plunkett 2004; Plunkett et al. 2004a; Nicolas & Plunkett 2009). The S.W. Australian genera Neosciadium and probably Homalosciadium also belong to Hydrocotyloideae (Andersson et al. 2006). Hydrocotyle has laterally flattened fruits with a sclerified (= woody) endocarp and stipules that are either cauline or are borne on the leaf base. Trachymene (perhaps inc. Uldinia) is also to be placed in Hydrocotyloideae; morphologically it is rather similar to them, and although there is a carpophore in the fruit, it is undivided. Astrotricha and Osmoxylon may be part of a polychotomy at the node immediately above Hydrocotyloideae (see also Lee et al. 2008), while the position of Harmisopanax, which has fruits that are schizocarpic like those of Hydrocotyloideae, is also uncertain (Nicolas & Plunkett 2009).

For more details on the phylogeny of Aralioideae in particular, see Henwood and Hart (2001) and especially Wen et al. (2001), Plunkett et al. (2004a, c), and Lowry et al. (2004). Although Schefflera is apparently polyphyletic, there is no strong support for particular phylogenetic positions of the groupings into which it breaks. These are circumscribed geographically, e.g. African plus Madagascan taxa form a clade, and in large part represent earlier infrageneric groupings (Plunkett et al. 2005, 2009; Gostel et al. 2009). Lee et al. (2008) focused on relationships of Malesian Araliaceae; Osmoxylon was isolated.

Classification. For a checklist of the family, see Frodin and Govaerts (2003). Generic limits in Aralioideae need much attention.

Myodocarpaceae + Apiaceae: furanocoumarins +; inflorescence panicles or racemes.

MYODOCARPACEAE Doweld   Back to Apiales

Plants woody; ?coumarins; apotracheal (and paratracheal) parenchyma +; leaves pinnately compound (simple), margin entire (serrate), venation brochidodromous; pedicels articulated; K valvate, C imbricate; A inflexed in bud, nucellus?, ventral carpel bundles fused bundles of adjacent placentae; fruits terete, fleshy, (dry, winged, seeds laterally flattened - Myodocarpus), endocarp with large oil ducts [different from vittae].

2 (Myodocarpus, Delarbrea)/19. New Caledonia, E. Malesia, and Queensland, Australia (map: from van Balgooy 1993). [Photo - Habit]

Chemistry, Morphology, etc. Myodocarpus has a number of distinctive features of the flower and in particular fruit features (compound umbel; schizocarp), the latter of which may be associated with wind dispersal. Indeed, the mericarps are beautiful little samaras that at first sight are similar to those of Serjania! It has been suggested that in wood anatomy Myodocarpus is perhaps more like Cornaceae than any other members of the Apiaceae-Araliaceae complex, but in other features it is more like Apiaceae (Rodrigues C. 1957).

Some information is taken from Lowry (1986), Raquet (2004), and Plunkett et al. (2004b).

Previous Relationships. This group used to be included in Araliaceae - Myodocarpeae.

APIACEAE Lindley, nom. cons.//UMBELLIFERAE Jussieu, nom. cons. et nom. alt.   Back to Apiales

Plant usu. herbaceous; pyranocoumarins, myricetin, mannitol +, umbelliferose [raffinose (trisaccharide) isomer] the storage carbohydrate; hydroxycoumarins, flavones 0; vessel elements aggregated; axial parenchyma scanty, paratracheal; stomata various; leaf also supervolute, base ± encircling stem; K reduced to ring of teeth (obsolete), C free, clawed, valvate, usu. with inflexed tips, vein single, unbranched [?all]; A inflexed in bud, ventral carpel bundles are fused bundles of the same placenta, funicle "short", stigma usu. capitate; fruit dry (fleshy), schizocarpic, mesocarp lignified, crystals single, rhombic, in small-celled inner layer, endocarp woody, 2(+) cell layers thick, sclereidal-fibrous, carpophore +; exotestal cells thin-walled.

434[approx. list]/3780 - 5 main groups below. World-wide, esp. N. temperate.

1. Mackinlayoideae Plunkett & Lowry

Plants woody (herbaceous); (centellose [oligosaccharide] - Centella); apotracheal (+ paratracheal) parenchyma; (leaf irregularly palmately compound - Mackinlaya); (pedicel not articulated); (K petaloid), nucellus?; (carpophore 0, but fused ventral bundles; rib oil ducts + [not Diposis, Klotzschia)).

7-9/93: Centella (40), Xanthosia (25), Actinotus (18). Most S. Pacific Rim, Centella esp. S. Africa, C. asiatica pantropical.

Synonymy: Actinotaceae Konstantinova & Melikian, Mackinlayaceae Doweld

Platysace [Azorelloideae [Saniculoideae + Apioideae]]: umbels often compound.

2. Platysace

(Oil ducts in ribs); K 0; cotyledons rounded, toothed.

1(-2)/26. Australia, most in the southwest (map: FloraBase viii.2009).

Azorelloideae [Saniculoideae + Apioideae]: fruits dorsally flattened; irregular anastomosing and/or branching mesocarp vittae +.

3. Azorelloideae Plunkett & Lowry

(Cork cambium deep-seated - Mulinum); (leaves compound), stipules +; nucellus "large", 2-4 megasporocytes, embryo sac tetrasporic, 16-nucleate [more than one embryo sac "type"], nucellus relatively persistent; fruit with wings/ribs [made up of the entire fruit wall, including a vascular bundle], lateral wings usually largest, (carpophore 0, fused ventral bundles +/0), druses in outer mesocarp - Azorella), companion cells [oil canals associated with the vascular bundles] +, inner layer of endocarp fibers running longitudinally [?distribution]; x = ?8.

21/155: Azorella (70: ?inc. Laretia, Mulinum). South American-Australian, Antarctic islands; Drusa glandulosa from the Canary Islands and Somalia! (map: from Bramwell 1972). [Photo - Habit.]

Saniculoideae + Apioideae: basal leaf with pinnate venation [?level], stipules 0; ovules tenuinucellate [incompletely so], nucellar cap +, funicle "long"; secondary [i.e. lateral] ribs +, mesocarp cells lignified, endocarp single cell layer thick, parenchymatous, (walls lignified), calcium oxalate as druses dispersed in mesocarp and around commissure, intrajugal vittae [oil ducts in the ribs] + [?level].

4. Saniculoideae Burnett

Kaurene-type terpenoids +; inflorescence apparently a simple umbel (a capitulum - Eryngium; pseudoracemose - Sanicula) [probably reduced compound umbels], with showy inflorescence bracts; style separated from disc by a narrow groove; intrajugal secretory ducts/cavities +; cotyledons rounded.

10/335. World-wide (map: see Meusel et al. 1978; Hultén & Fries 1986).

4a. Lichtensteinia, etc.

?

2/8. South Africa, Saint Helena.

Steganotaenieae + Saniculeae: ?

4b. Steganotaenieae C. I. Calviño & S. R. Downie

Plant woody; fruits 2-3 winged [wings exo- and mesocarp alone], intrajugal secretory ducts/cavities associated with the wings much expanded, carpophore +, (dispersed mesocarp druses 0); n = ?

2/2-3. Tropical Africa, S.W. Cape.

4c. Saniculeae Burnett

(R)-3'-O-ß-D-glucopranosylrosmarinic acid +; leaves blades often broad, (compound), with hairy or spiny tips to the teeth; (flowers blue), carpellate flowers sessile; fruit scaly or spiny, carpophore 0, (intrajugal secretory ducts/cavities 0), (dispersed crystals throughout mesocarp 0), endocarp not lignified; n = 8 (9, 11, 12).

8/333: Eryngium (250). World-wide (map: see Meusel et al. 1978; Hultén & Fries 1986).

Synonymy: Eryngiaceae Rafinesque, Saniculaceae (Burnett) A. & D. Löve

5. Apioideae Seemann

Flavones, methylated flavonoids, furanocoumarins, phenylpropenes +; leaves usu. compound; (outer flowers of umbel monosymmetric); hypostase +, stylopodium lacking groove; (fruit not flattened), carpophore free, bifid [mericarps attached at apex], intrajugal oil ducts 0, vallecular vittae +, (+, 0 - Lichtensteinia), [crystals on commissural side of mericarp only, or none [although these characters are common, it is unclear which, if any, is an apomorphy]), endocarp not lignified; x = 11; cotyledons (1), various.

400/3200: Bupleurum (190), Ferula (175), Pimpinella (150), Angelica (110), Seseli (110), Peucedanum s.l. (110), Lomatium (74), Heracleum (65), Chaerophyllum (60), Arracacia (55), Ligusticum (50). Worldwide, esp. N. temperate (map: see Meusel et al. 1978; Hultén & Fries 1986).

Synonymy: Ammiaceae Barnhart, Angelicaceae Martynov, Bupleuraceae Martynov, Coriandraceae Burnett, Daucaceae Martynov, Ferulaceae Saccardo, Imperatoriaceae Martynov, Pastinacaceae Martynov, Smyrniaceae Burnett

• Apiaceae are recognisable by their usually herbaceous habit and compound leaves with broad, sheathing base; inflorescences that are usually umbels of umbels, rarely heads; and polypetalous flowers usually with a minute calyx, clawed petals with incurved apices, and two carpels; the fruits are dry and schizocarpic.

• Saniculoideae have usually undivided leaves with hairs or spiny tips to the teeth, sessile and spiny or scaly fruits, an often apparently more or less simple umbel or head, and there is no free carpophore.

• Apioideae usually have more or less finely-divided leaves, compound umbels, and the usually pedicellate fruit has a free, bifid carpophore.

Evolution. Caterpillars of Papilionideae butterflies are notably common (ca 13% of all records) on Apiaceae, but not on either Pittosporaceae or Araliaceae; thus they will not eat Hydrocotyle (here Araliaceae), many of the larvae of Papilio ajax tested absolutely refusing to eat it (see also Dethier 1941; Ehrlich & Raven 1967). Linear fumarocoumarins are often phototoxic but are tolerated by caterpillars that will not eat plants with the non-photoxic linear coumarins (Berenbaum & Feeney 1981). Microlepidopteran larvae of the Elachistidae - Depressariinae are common on Apiaceae, although they may have initially been associated with rosids and have also colonized some Asteraceae (Fetz 1994 for host plants; Berenbaum & Zangerl 1998 for the chemistry of the [co]evolution of resistance; Berenbaum & Passoa 1999 for a phylogeny). There has been a diversification of agromyzid dipteran leaf miners in north temperate Apiaceae; thye were previously on Ranunculaceae, also with noxious secondary metabolites (Winkler et al. 2009). For general insect-umbellifer relationships, see Berenbaum (1990) and Sperling and Feeny (1995).

Apioideae are likely to have evolved in Southern Africa, but although a number of taxa from there have a woody habit, the ancestral condition for this subfamily, at least, is likely to be herbaceous (Calviño et al. 2006).

Variation in leaf morphology, even within Apioideae, is considerable. Thus the small circum-Pacific genus Oreomyrrhis includes species with ordinary-looking highly dissected leaves, leaves with a series of almost tooth-like leaflets on either side of the rachis, linear leaves, sometimes lobed at the apex, although the lobes are not articulated, and small, undivided leaves. In the last case the plant is tussock-forming and almost moss-like - specimens have even been identified as Centrolepidaceae, a monocot! All the leaf morphologies are found on the mountains of New Guinea. The genus is probably monophyletic, but it is well embedded in Chaerophyllum, a genus hitherto thought to be fairly well understood (Chung et al. 2005; Chung 2007). Lilaeopsis occidentalis and Oxyopolis greenmanii have linear, terete leaves that are marked by articulations at intervals. These leaves are comparable with the rhachis of compound leaves, hydathodes borne at the articulations representing much reduced and modified pinnae (Kaplan 1970b, cf. esp. Figs 3E and 6A). Other North American taxa have similar leaves, and they appear to have evolved several times (Feist & Downie 2008). Bupleurum rotundifolium has almost orbicular, entire, perfoliate leaves, hence its common name, thorow wax.

Chemistry, Morphology, etc. Gums and resins are scattered in the family. For the distinctive rosmarinic acid glucoside found in Saniculoideae-Saniculeae, see Olivier et al. (2008). Peripheral collenchyma in the stem is often especially well developed, and petiole anatomy is very variable and complex (e.g. Metcalfe 1950). Taxa such as Foeniculum have stipules of sorts. Centella has a few branches from the petal bundle (Gustafsson 1995); petal vasculature may repay attention. Spichiger et al. (2002) show the two carpels as being collateral. According to Eyde and Tseng (1971), whether the ventral carpel bundles are fused bundles of adjacent placentae or are from the same placenta varies within Apiaceae without any particular systematic significance. Van Tieghem (1898) noted that in Apiaceae the ascending ovule aborts and the pendulous ovule persists, however, other reports suggest that both ovules are pendulous (Philipson 1970).

For chemistry, see Hegnauer (1971) and Berenbaum (2001), for wood anatomy in Apioideae-Heteromorpheae, see Oskolski and van Wyk (2008), for the distribution of the hypostase, see Gupta (1970), for embryo sac morphology and fruit anatomy, esp. of genera in the old Hydrocotyloideae, see Tseng (1967), for a useful discussion of characters mainly in the context of Southern African taxa, see Burtt (1991a), for genera, old style, see Pimenov and Leonov (1993), for pollen of Chinese Apiaceae, see Shu and She (2001), for chromosome number and morphology, see Pimenov et al. (2003), for floral development, see Leins and Erbar (2004b), for vittae and druses in the fruits, see Liu et al. (2007), and for fruit anatomy of Azorelloideae, see Liu et al. (2009). There is much useful information in Chandler and Plunkett (2003, 2004). I am particularly indebted to Mark Watson for comments on Apiaceae s.l.; mistakes remain mine.

Phylogeny. The old Hydrocotyloideae are hopelessly polyphyletc, and their members now occur in several quite separate clades of which most are still in Apiaceae (Nicolas & Plunkett 2009). Some genera of Mackinlayoideae used to be in Araliaceae - Mackinlayeae, others in Apiaceae - Hydrocotyloideae; included are Apiopetalum, Mackinlaya, Micropleura, Xanthosia. See Melikian and Konstantinova (2006) for discussion on the gynoecial structure of Actinotus which they consider to be so different from that of other Apiaceae that it merits the genus being placed in its own family; it is to be included in Mackinlayoideae, although its position within the clade is unclear (Nicolas & Plunkett 2009).

Platysace - perhaps to include Homalosciadium - is not a member of Mackinlayoideae, where it had been placed (e.g. Chandler & Plunkett 2004). It seemed to be sister to other Apioideae in some analyses (Henwood & Hart 2001; Andersson et al. 2006), but a position rather deep in the tree sister to [Azorelloideae [Saniculoideae + Apioideae]] is strongly supported (Nicolas & Plunkett 2009). The positions of Klotzschia ("distinctive fruits") and Hermas (free carpophores; endocarp fibrous/woody, single crystals in mesocarp cells, congested umbels, n = 7 - for the latter two characters, cf. Saniculoideae), both of which used to be in Hydrocotyloideae, are also unclear (Andersson et al. 2006; Calviño et al. 2006, 2008); the former may go with Azorelloideae (see below). The latter, a South African endemic, is unlikely to be placed within any currently recognized subfamily (Nicolas & Plunkett 2009), although there is some support for a position as sister to [Saniculoideae + Apioideae].

For the composition of Azorelloideae, in which are to be placed about half the genera that used to be included in Hydrocotyloideae, see Downie et al. (1998, 2000a, 2001), Mitchell et al. (1999), Plunkett & Lowry (2001), Henwood and Hart (2001: the Bowlesia clade), Chandler and Plunkett (2004), Andersson et al. (2006) and Nicolas and Plunkett (2009), the latter of which see for details. Azorelloideae include Asteriscium (polyphyletic), Azorella (polyphyletic), Bolax, Bowlesia, Dichosciadium, Dickinsia, Diplaspis, Diposis, Domeykoa, Drusa, Eremocharis, Gymnophyton, Homalocarpus, Huanaca, Laretia, Mulinum, Oschatzia, Pozoa, Schizeilema, Spananthe, Stilbocarpa (this used to be in Araliaceae; it is probably sister to the Andean Huanaca). Klotzschia may also belong here, but its position is not stable and it may be a member of Apioideae; this genus aside, Diposis is sister to other Azorelloideae (Nicolas & Plunkett 2009). Bowlesia lacks petroselenic acid, but it was apparently the only genus of this group studied (Kleiman & Spencer 1982).

Monophyly of the distinctive Saniculoideae (except Lagoecia, now in Apioideae) is upheld in all molecular analyses, and details of relationships within it are given by Valiejo-Roman et al. (2002). In some analyses the African ex-hydrocotyloid Arctopus is sister to other Saniculoideae, and the woody Steganotaenia and Polemanniopsis, and perhaps Lichtensteinia, were probably also part of the same clade (Downie et al. 2001; van Wyck 2001; M. Liu et al. 2003; Plunkett et al. 2004c); at least some of the latter genera have a slightly lignified endocarp, apparently alone in both Saniculoideae and Apioideae (M. Liu et al. 2004). Calviño et al. (2006, esp. 2007 for a good general discussion of variation), however, expressed reservations about this expanded - and characterless - Eryngioideae, while Calviño and Downie (2007) found that the clade could be circumscribed satisfactorily so long as Lichtensteinia was excluded and placed in Apioideae; they recognised two tribes, both well supported and with unique indels. Carpophores, chromosome numbers other than 8, and inflorescences that are not condensed (all in African taxa) could be plesiomorphic in the clade (see also Calviño et al. 2008a; Kadereit et al. 2008). The usually compact inflorescence units of Saniculoideae seem best interpreted as a group of reduced umbellules (Froebe 1964, 1971). The large genus Eryngium has separate New and Old World clades (Calvinño et al. 2008b). However, Nicolas and Plunkett (2009) found that a clade including Lichtensteinia and Choritaenia were weakly supported as being sister to other Saniculoideae; I have placed them in this position above, but I have not integrated them morphologically into the subfamily.

Within Apioideae, some taxa are woody, e.g. the Southern African Bupleurum fruticosum and a number of other Southern African taxa (Calviño et al. 2006); Myrrhidendron, from Central America and Colombia, is also woody. Relationships within the subfamily are something like [Lichtensteinia [Annesorhiza clade [Heteromorpheae (mostly woody, African; vessel element walls with helical thickenings) [Bupleurum + The Rest]]]] (Downie & Katz-Downie 1999; Plunkett et al. 2004; Calviño et al. 2006; Magee et al. 2008, also a revision of Ezosciadium). Apart from the position of Lichtensteinia, here in Saniculoideae but in some analysis sister to [Saniculoideae + Apioideae], relationships in Nicolas and Plunkett (2009) are similar; above Bupleurum on the tree was Neogoezia. Among "basal" Apioideae are clades made up largely of Southern African genera (see Burtt 1991a for information on southern African taxa) and strongly supported as sister to the rest of the subfamily (as Calviño et al. 2006 note, this has considerable implications for synapomorphy positions). The Annesorhiza clade is perhaps allied to Heteromorpheae (including Pseudocarum, which has branching/anastomosing vittae); Bupleurum also has branching vittae and is strongly supported as sister to the remainder of the subfamily (Calviño et al. 2005, 2006). Apioideae include Lagoecia.

For other relationships within Apioideae, see e.g. Downie et al. (2000a, b, 2001, 2002), Hardway et al. (2004), Plunkett and Downie (2000 - variation in size of chloroplast inverted repeat characterises a large clade in Apioideae), Spalik and Downie (2001a, b), Sun and Downie (2004), Sun et al. (2004: Cymopterus and Lomatium about as polyphletic as you can get), Kurzyna-Mlynik et al. (2008: Ferula, somewhat paraphyletic, and relatives), Downie et al. (2008: Oenantheae), Zhou et al. (2008: China), Ajani et al. (2008: Iran), Winter et al. (2008: Africa), Sun et al. (2008: Ligusticum in China), Degtjareva et al. (2009: Bunium polyphyletic, monocotyledonous species separate), Spalik et al. (2009: Sium area), Magee et al. (2009: especially Cape genera).

Classification. The subfamilial classification of Plunkett et al. (2004c) is followed here, but additions will be needed given the positions taken by ex Hydrocotyloideae in the tree recovered by Nicolas and Plunkett (2009). Generic and tribal limits in Apioideae are something of a disaster area. The traditional tribal and generic classification was based primarily on fruit morphology and is problematic; convergence of fruit architecture as adaptations to modes of fruit dispersal has resulted in many non-monophyletic groupings. Recent studies using molecular techniques are demonstrating the problems with the traditional classifications and are beginning to resolve generic and tribal affinities. For instance, 13/18 genera for which two or more sequences were included in in a study by Downie et al. (2000b) were found not to be monophyletic. The problem is further compounded by the disproportionately large number of mono- or di-typic genera (see also Spalik et al. 2001; Valiejo-Roman et al. 2006; Spalik & Downie 2007). Indeed, just about all the papers dealing with phylogenetic relationships in Apioideae (see above) have implications for generic limits there.