EXTANT SEED PLANTS

Plant woody, evergreen; nicotinic acid metabolised to trigonelline; primary cell walls rich in xyloglucans and/or glucomannans, 25-30% pectin [Type I walls]; lignins rich in guaiacyl units; true roots present, xylem exarch, branching endogenous; arbuscular mycorrhizae +; shoot apical meristem complex; stem with ectophloic eustele, endodermis 0, xylem endarch, branching exogenous; vascular tissue in t.s. discontinuous by interfascicular regions; vascular cambium + [xylem ("wood") differentiating internally, phloem externally]; wood homoxylous, tracheids +; tracheid/tracheid pits circular, bordered; sieve tube/cell plastids with starch grains; phloem fibers +; stem cork cambium superficial, root cork cambium deep seated; nodes ?; stomata ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral, veins -5(-8) mm/mm²; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, grains mono[ana]sulcate, exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development first endo- then exosporic, tube developing from distal end of grain, to ca 2 mm from receptive surface to egg, gametes two, with cell walls, with many flagellae; female gametophyte endosporic, initially syncytial, walls then surrounding individual nuclei; seeds "large", first cell wall of zygote transverse, embryo straight, endoscopic [suspensor +], short-minute, with morphological dormancy, white, cotyledons 2; plastid transmission maternal; two copies of LEAFY gene, PHY gene duplication, mitochondrial nad1 intron 2 and coxIIi3 intron present.

MAGNOLIOPHYTA

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

Possible apomorphies are in bold. Note that the actual level to which many of these features, particularly the more cryptic ones, should be assigned is unclear, because some taxa basal to the [magnoliid + monocot + eudicot] group have been surprisingly little studied. Furthermore, details of relationships among gymnosperms will affect the level at which some of these characters are pegged.

NYMPHAEALES [AUSTROBAILEYALES [[CHLORANTHALES + MAGNOLIIDS] [MONOCOTS [CERATOPHYLLALES + EUDICOTS]]]]: vessels +, elements with scalariform perforation plates; nucleus of egg cell sister to one of the polar nuclei; ?genome duplication; "DEAER" motif in AP3 and PI genes lost, gaps in these genes.

[[SABIACEAE + PROTEALES] [TROCHODENDRALES [BUXALES + CORE EUDICOTS]]]: (axial/receptacular nectary +).

PROTEALES Dumortier  Main Tree, Synapomorphies.

Epidermal waxes with tubules [2/3], nonacosan-10-ol the main wax; nodes?; leaf teeth?; stipules surrounding stem [2/3]; 1-2 pendulous ovules/carpel [?really an apomorphy], stigma dry; seed coat?; endosperm development?, slight or 0, embryo long. - 3 families, 82 genera, 1610 species.

Thorne (2007) includes the order, variously broken up, along with Sabiales and Buxales, in his hetereogeneous Ranunculidae.

Both Nelumbonaceae and Platanaceae are known as fossils from the Albian (the dates are ca 106 and ca 110 million years before present, respectively; for the former records, see Upchurch & Wolfe 2005), and Anderson et al. (2005, using both molecular and fossil data) date stem group Platanales from 121-119 million years before present, divergence beginning 121-115 million years before present. From the molecular point of view, at least, both Platanus and Nelumbo can perhaps be thought of as living fossils (Sanderson & Doyle 2001).

Chase et al. (1993) and Drinnan et al. (1995) found Platanaceae and Nelumbonaceae to be sister taxa, yet Barthlott et al. (1996) noted that the cuticle waxes of Platanaceae and Nelumbonaceae were very different. Indeed, although the order is small, it seems uncomfortably heterogeneous; it has moderate support in molecular analyses. Hayes et al. (2000) emphasise that there are only two sepals in Nelumbo, and possibly the whole order can be characterised as having dimerous flowers (see Doyle & Endress 2000 for Proteaceae).

Nelumbonaceae used to be associated with Nymphaeaceae, the two having superficially similar flowers and vegetative body (both are aquatics). Takhtajan (1997) removed Nelumbonaceae from the vicinity of Nymphaeales, but considered it to be a very isolated group and placed it alone in his subclass Nelumbonidae.

For variation in microsporogenesis and pollen morphology, see Furness and Rudall (2004).

Includes Nelumbonaceae, Platanaceae, Proteaceae.

Synonymy: Nelumbonales Willkommen & Lange, Platanales J. H. Schaffner - Proteanae Takhtajan, Nelumbonanae Reveal - Nelumbonidae Takhtajan - Nelumbonopsida Endlicher, Proteopsida Bartling

NELUMBONACEAE Berchtold & J. Presl, nom. cons.   Back to Proteales

Aquatic herbs; aporphine alkaloids +; radicle aborts; cork?; vascular bundles scattered, lacking fibrous sheath; tubular P-protein and rod-shaped bodies +; nodes ?; articulated laticifers +; cuticle waxes as clustered tubules; prophyll adaxial; leaves in groups of three along the stem, vertically two-ranked, sheathing cataphyll on one side then cataphyll and expanded leaf on the other side; leaf peltate, involute, main veins dichotomous, proceeding to margin, stipule sheathing, open; flowers ?axillary, large, with cortical vascular system; K 2, C 10-30, spiral, A many, from a ring meristem, at least outer extrorse, connective with a terminal appendage, receptacle massive, with emergent druses, G (2-)10-30, carpels ascidiate, immersed in receptacle, occluded by secretion, pollen canal long-papillate, one pendulous ovule/carpel, outer integument ca 30 cells and inner integument 8-10 cells thick, nucellar cap and funicular obturator +, antipodals multiplying, multinucleate, stylodium 0, stigma expanded, wet; fruit a nutlet, with an apical pore; seed ?pachychalazal, testa undistinguished; embryo green, large, with a tubular but basically double cotyledon, several leaf primordia, radicle aborting, roots adventitious; n = 8.

1[list]/1-2. Temperate, E. North America and E. Asia (Map: from Fl. N. Am. III 1997; Fu & Hong 2000; Sculthorpe 1987; Wu 1983 [the last two include all Malesia and N. Australia, but not there in NW Australia, at least, in FloraBase 2006, the former also includes the Antilles and NW South America...]). [Photo - Nelumbo Flower © J. Manhart, Collection.]

• Nelumbonaceae are water plants that are easily recognised by their peltate leaves with dichotomous main venation that are held above the water surface like parasols, and their flowers which are like those of water lilies but have free carpels immersed in a large, obconical receptacle.

Vogel (2004a) provides a fascinating account of air circulation in Nelumbo. The flowers are thermogenic, with breakdown of starch in the expanded receptacle (Vogel & Hadacek 2004; Watling et al. 2006). Stem group Nelumbonaceae have been dated from 121-115 million years before the present (Anderson et al. 2005), while fossils of Nelumbonaceae - as Nelumbites, the leaves with rather different venation but the flowers with the distinctive expanded floral receptacle of extant Nelumbo - are reported from the early Cretaceous from the mid to late Albian (Upchurch & Wolfe 2005).

Understanding how Nelumbo grows is difficult. The cataphylls more or less surround the stem and presumably represent the stipular portion of the leaf. Axillary branches show the same arrangement of leaves as described above, but with the addition of the prophyll which is on the same side of the branch as the first cataphyll. Flower buds develop in the axis of the second cataphyll, axillary branches in the axil of the expanded leaf, however, other interpretations are also possible. The sheathing stipule associated with the foliage leaf is open on the side of the stem opposite to the leaf insertion.

Vessels arise first in the roots, but are also found in the rhizome, and the trend of their specialisation is similar; this is the monocot pattern. Details of the root cortex of Nelumbonaceae differ considerably from those in Nymphaeales (Seago 2002). Although the vascular bundles are scattered in the stem, there is an endodermis present. The two sepals are inserted in the vertical plane. Stamens develop from an androecial ring, and they and the carpels may be irregularly whorled (Hayes et al. 2000). The pollen tectum is reticulate. The sharp-pointed and often six-rayed epidermal druses on the surface of the receptacle may protect it against herbivores (Vogel 2004b).

Cronquist (1981) describes the stamens as being introrse-latrose; Endress (1995) as extrorse, Takhtajan (1997) as extrorse (the outer members) and introrse (the others). There is also disagreement over endosperm development, which has been variously described as nuclear, cellular, or helobial; pollen morphology (Kreunen & Osborne 1999); and growth pattern (cf. Eichler 1878; Wignand & Dennert 1888; Miki 1926; Esau & Kosakai 1975).

Both the morphology of the cuticle waxes and plant chemistry suggest a relationship with Ranunculales, but there the waxes are nonacosan-10-ol rather than 4-10- or 5-10-diol (Barthlott et al. 1996, the difference not emphasised by Barthlott et al. 2003).

Some general information is taken from Williamson and Schneider (1993) and Hayes et al. (2000), for chemistry, see Hegnauer (1969, 1990 - under Nymphaeaceae), for the receptacular druses, see Vogel (2004b).

Platanaceae + Proteaceae: woody; non-hydrolysable tannins, myricetin +, benzylisoquinoline alkaloids 0; (pits vestured); wood with broad rays [8+-seriate]; stomata laterocytic; flowers 4-merous [see fossil Platanaceae], stamens equal and opposite perianth members, carpels with 5 vascular bundles, hairy, postgenital fusion complete, ovules straight [atropous], style long; endosperm nuclear.

Synonymisation of Platanaceae under Proteaceae is optional in A.P.G. II, however, there is little to recommend it.

That Platanaceae and Proteaceae are sister taxa may explain why there are so many leaf fossils from the southern hemisphere that are "platanoid" in their general aspect (K. Johnason, in Drinnan et al. 1994; Hoot et al. 1999). For stomatal morphology, see Carpenter et al. (2005).

The wood anatomy of Proteaceae and Platanaceae is very different, although the former have concave vessel-parenchyma festoons and the latter concave growth ring boundaries in common, in addition to their broad rays. These differences may be connected with the different climatic conditions under which the two groups grow (Baas et al. 2003).

PLATANACEAE T. Lestibudois, nom. cons.   Back to Proteales

Cork in outer cortex; nodes multilacunar; petiole bundle annular, wing bundles +; hairs candelabriform; growth sympodial; leaves two-ranked (spiral), plicate, teeth glandular, with a cavity, higher order veins approach but do not enter (margin entire), 2 strong 2ndary veins near base (pinnate; also seedlings), petiole enclosing the axillary bud (not), stipule tubular, closed (adaxial-sheathing, open); plant monoecious; inflorescences capitate; flowers with odd member of outer whorl abaxial, P connate or not, often lacking vasculature; staminate flowers: P ca 3, tiny, free, anthers valvate, connective peltate, pollen semitectate-reticulate, 16-22 µm long, (pistillodes +); carpellate flowers: P 3-4, G (3-)5-8(-9), 1(-2) pendulous ovules/carpel, inner integument ca 5 cells thick, stigma decurrent in two crests, ± dry; fruit an achene, with tuft of basal hairs; testa with hypodermal layer of thickened cells; seed reserves hemicellulosic; n = 16-21.

1[list]/10. North Temperate (Map: from Fl. N. Am. III 1997; Jalas et al. 1999 [Europe]; Feng et al. 2005). [Photo - Leaves & Stipules, Collection.]

• Platanaceae are a distinctive family. The bark commonly exfoliates with characteristic plates, the leaves have leaf-like stipules completely surrounding the stem, the petiole base encloses the axillary bud, and the blades have subpalmate venation. However, Platanus kerrii is rather different vegetatively from the other species, having stipules that are more or less scarious, an axillary bud that is not enclosed by the petiole base, and pinnate venation. In all species, the inflorescences are capitate and made up of numerous small flowers: the fruits are small achenes with tufts of basal hairs.

Platanaceae are known fossil from the Lower Cretaceous, 98-113 million years before present (Platanocarpus - Crane et al. 1993). Anderson et al. (2005) date stem group Platanaceae to 119-110 million years before present. The morphology of these fossil plants differs in several respects from that of their extant relatives. Thus inflorescences in Upper Cretaceous plants may have sessile or pedunculate heads, in staminate flowers P 4, basally connate, stamens equal and opposite perianth members and arising from a short ring of tissue, alternating with ?staminodes, perhaps of an inner whorl, or two 4- or 5-membered whorls of perianth present, pistillode consistently present; in carpellate flowers often 4-5-merous, P in 2 whorls, connate, outer more or less completely so, or free, G 8, 2 opposite each member of inner perianth, ovules perhaps anatropous, style 0, no achenial hairs, etc. Fossils assigned to Platanus may have trifoliolate leaves (Kvacek et al. 2001), while other fossils have somewhat smaller pollen that that of extant taxa - are they wind-pollinated? - and tricolporate pollen has even been found in situ in fossils assigned to Platanaceae (e.g. Manchester 1986; Crane et al. 1993; Pedersen et al. 1994; Friis et al. 1988; Magallón-Puebla et al. 1997: Mindell et al. 2006: Crepet et al. 2004 for other references). Fossils with the distinctive petiole bases of subgenus Platanus are abundant in the Palaeocene some 60 million years before present (Feng et al. 2005: note that subgenus Castaneophyllum [P. kerrii] lacks them). Finally, there is some evidence from stomatal size of fossils that polyploidization occured within this clade (Masterson 2004).

For a phylogeny of Platanus, see Grimm and Denk (2008). There is some variation in stomatal morphology (Carpenter et al. (2005). Developmental studies suggest that flowers of Platanus are basically 4-merous (A. Douglas in Hoot et al. 1999).

Hennig et al. (1994) describe the cuticle wax as lacking crystalloids, Fehrenbach and Barthlott (1988) as having rodlets and platelets. Smets (1986) mentions the presence of nectaries; Melikian (1973) and Takhtajan (1991) describe testa anatomy; Floyd et al. (1999) describe the embryology; for chemistry, see Hegnauer (1969, 1990). Endress (1971) describes the flower as having the odd perianth member abaxial; he also describes the 6 carpels as being opposite sepals + C. Some information is taken from Kubitzki (1993b).

Included in Hamamelidales by Takhtajan (1997).

PROTEACEAE Jussieu, nom. cons.   Back to Proteales

Trees or (acaulescent) shrubs; lateral roots of limited growth, forming clusters [proteoid roots], plant rarely mycorrhizal; cyanogenic glycosides +; vessel elements with simple perforation plates (scalariform, bars few); true tracheids and libriform fibers +; phloem stratified or not, rays broad; (nodes 1:1); sclereids common; hairs with 2 short cells, one in epidermis, apical cell elongated, bifid or not; leaves spiral (opposite; odd-pinnately (palmately) compound or lobed), usu. conduplicate, often thick, margins spiny toothed to entire, base of petiole often swollen, stipules 0; inflorescence various; flowers 4-merous, P valvate, pollen triangular in polar view, oblate, porate, pores broadly operculate, arranged according to Garside's Rule [three pores at four points in the tetrad], (colpate), nectary receptacular, G 1, vascular bundles forming a ring in the chalazal region, stigma terminal or lateral, often slit-like, secretory; endotesta palisade, crystalliferous, (exotegmen fibrous); cotyledons large, suspensor 0.

80[list]/1600 - five subfamilies below. Largely southern hemisphere, esp. Australia and S. Africa (Map: from Johnson & Briggs 1975; Weston 2006; Prance et al. 2007).

1. Bellendenoideae P. H. Weston

Al accumulation +; bracts 0; 2 ovules/carpel; fruit dry, indehiscent, 2-winged; endosperm at most slight; n = 5, chromosomes ca 6.7 µm long (mean).

1/1: Bellendena montana. Australia (Tasmania).

Cotyledons of Bellendena are not cordate are they often are elsewhere in the family.

Persoonioideae [Grevilleoideae + Symphionematoideae + Proteoideae]: stomata brachyparacytic; P connate, A adnate to P, more or less sessile, (connective appendage +), usu. 4 nectary lobes +; endosperm +.

2. Persoonioideae L. A. S. Johnson & B. Briggs

Al accumulation infrequent [e.g. Placospermum]; proteoid roots 0; 1-2(+) ovules carpel; fruit a drupe (follicle - Placospermum); cotyledons obreniform; n = 7, chromosomes 9.1-14.4 µm long (mean).

5/110: Persoonia (100). Mostly Australia, also New Caledonia and New Zealand.

A small, almost spine-like process occurs just abaxial to the apex of the perianth members (see Kaplan 1973) in this subfamily, but it also occurs elsewhere in the family.

Grevilleoideae + Symphionematoideae + Proteoideae: flowers vertically or obliquely monosymmetric [P split to base on one side, or 3 P connate, 1 free], (secondary pollen presentation, the apex of the style bearing the pollen), (ovules anatropous); x = 14, chromosomes 0.5-5 µm long (mean).

3. Grevilleoideae Engler

Plants Al accumulators; sieve elements with rosette-like non-dispersive protein bodies; paired flowers subtended by a common bract very common; pollen with abundant endexine in the apertural region, (1-)2+ ovules/carpel; fruit a drupe or follicle, the latter with winged seeds; (seeds pachychalazal); endosperm with chalazal ± nuclear haustorium; cotyledons basally auriculate; n = (10-)14(-15).

45/855: Grevillea (515, inc. Hakea, Finschia), Helicia (100), Banksia (175: inc. Dryandra, see Mast et al. 2005). Australia and the S.E. Pacific to Southeast Asia, S. India and Sri Lanka, South America, South Africa (Brabejum) and Madagascar (Madagascaria). [Photos - Grevillea Flower, Embothrium Flower, Fruit, Habit.]

Carnarvonia and Sphalmium are both morphologically very distinctive (and are segregated as Carnarvonioideae L. A. S. Johnson & B. Briggs and Sphalmioideae L. A. S. Johnson & B. Briggs in The Flora of Australia), but they are included in Grevilleoideae here. The two genera may be immediately related, and although definitely in Grevilleoideae, relationships within that clade are unclear.

Foliar anatomy is notably variable within this clade. For flower pairs, which represent reduced inflorescence branches, see Douglas and Tucker (1996a), for the variable floral orientation, see Douglas and Tucker (1996b).

Symphionematoideae + Proteoideae: fruit indehiscent.

4. Symphionematoideae P. H. Weston & N. P. Barker

Proteoid roots 0; nectaries 0, 1-2 ovules/carpel; fruit dry; n = also 10.

2/3. S.E. Australia, inc. Tasmania.

5. Proteoideae Eaton

Al accumulation infrequent; sieve elements with non-dispersive protein bodies; flowers sessile, (hypanthium +), (A monothecal; 1-3); 1(2) ovules/carpel; fruit often single-seeded, drupe or nut; n = (10-)11-13(-14).

25/640: Protea (115), Leucadendron (80), Conospermum (55), Petrophile (55), Synaphea (55), Serruria (50). Africa S. of the Sahara, esp. the Cape region, Australia.

The inflorescences of some species of Conospermum in particular look rather like those of Anigozanthus...

For relationships, see Barker et al. (2002); the Australian Isopogon and Adenanthos are sister to a clade that represents most of the subfamily, but not including Protea and Faurea (support strong for this set of relationships); unfortunately Eidothea, a distinctive genus and is segregated as Eidotheoideae in The Flora of Australia, was not included. However, the biogeography of the subfamily is clearly interesting.

• Proteaceae are woody plants that may be recognised by the broad rays in the wood, the surface of which is often furrowed, the often rather scleromorphic and coriaceous leaf blades with rather distant (or no) teeth and prominent reticulum, the swollen leaf base and the sometimes rather short petiole. The 4-merous flowers are often aggregated into conspicuous inflorescences; the perianth may be monosymmetric and curved and the stamens are opposite the perianth members; the single carpel often has a long style.

Hill et al. (1995) and Weston (2006) summarise the fossil record of the family. Anderson et al. (2005, see also Barker et al. 2007b) date stem group Proteaceae at 119-110 million years before present, crown group members at 96-85 million years before present. Leng et al. (2005) discuss small but mature capsular fruits from late Cretaceous (late Santonian/early Campanian) Sweden which have several attributes of Proteaceae, e.g. the flowers are paired, the stigma is somewhat abaxial on the fruit, however, there are also differences, including the fact that there are only three vascular bundles per carpel and there seems to be little in the way of a perianth; one species has the most remarkable papillate seeds. There is a great diversity of proteaceous pollen from the late Cretaceous (Campanian-Maastrichtian) in S.E. Australia (Dettmann & Jarzen 1991). Although some transoceanic disjunctions in the family such as that of the sister taxa Cardwellia in Australia and Gevuina in South America, are possibly caused by vicariance/drift events, others, like Brabejum in Africa which is sister to Panopsis in South America, involve genera whose divergence is later than the geological events that possibly caused them (Barker et al. 2007b). Several lines of molecular evidence suggest that there may have been a rapid diversification within Grevilleoideae (Hoot & Douglas 1998). The diversification of Protea, notably speciose in southern Africa, has been studied by Barraclough and Reeves (2005), although they find it difficult to pin down the timing of this.

Given the size of the family, caterpillars of Lycaenidae butterflies seem to eat its members quite frequently (see Fiedler 1991).

Pollination in the family has been studied in some detail, and in both Australia and southern Africa non-flying mammals (rodents, marsupials) are among the pollinators (Collins & Rebelo 1987). Secondary pollen presentation by regions at the apex of the style is common, and the pollen may even cover the stigmatic area (Ladd et al. 1996), but selfing is uncommon; Proteaceae show very great variation in these pollen presenting areas (Ladd 1994). Serotiny, the follicles opening only after a fire, is scattered in the family.

Proteoid roots are clusters of roots of determinate growth that have densely set root hairs; they exude organic acids into the soil and mobilize phosphate, and perhaps other nutrients that are at a premium in the phosphorous-poor soils on which members of the family are often found (Weston 2006). For the evolution of scleromorphic leaf anatomy, see Jordan et al. (2005, 2008); some of the structures involved are implicated in photoprotection and are associated with some combination of open, oligotrophic, cold and dry conditions. In general, Proteaceae are most diverse in rather dry climates in Australia and southern Africa; serotiny and lignotubers have evolved several times.

In Australia, the fungal pathogen Phytophthora cinnamomi is proving especially destructive to members of this family in the Mediterranean climates of the southwest.

For phylogeny, see Hoot and Douglas (1998) and Weston and Barker (2006). Although the subfamilies recognised here seem to be fairly solidly supported, relationships between them are less clear. The summary tree in Weston and Barker (2006) and Weston (2006) suggests that Bellendenoideae and Persoonioideae are sister taxa.

Sieve tubes have sieve areas for most of their length. The roots have 4-7 protoxylem poles. Nodes in Panopsis appear to be pentalacunar. Cotyledonary nodes commonly have split laterals (Naubauer 1991), however, the distribution of this character is unclear. The lenticels are often horizontally elongated (Keller 1996). There is no evidence that the uniseriate perianth is derived from a biseriate structure, and the individual members - of Macadamia, at least - have three traces; for the family, 1-5 bundles supplying each tepal are reported (Weston 2006). The nectary has very variable vasculature and is best considered an enation (Douglas & Tucker 1996c). The position of the embryo sac in the ovule varies considerably (Venkata Rao 1971). The stigma may be papillate, or it is more or less enclosed, with exudate (Matthews et al. 1999); due to the early growth of the carpel, it may be in a more or less abaxial position on the carpel/style. Testa and tegmen variation is considerable, parly because the fruits are sometimes indehiscent, and both may sometimes be multiplicative (Venkata Rao 1971; Corner 1976); however, the ovary wall and integuments may be adnate (so the fruit is a caryopsis??!!) and there has been much misinterpretation of fruit/seed anatomy (Manning & Brits 1993: their interpretation is followed here). That 'paleo-polyploidy' has been involved in the evolution of chromosome number in the family is questionable (Stace et al. 1998).

The testa anatomy is similar to that in Papaveraceae, Chloranthaceae, and Aristolochiaceae...

For Al-accumulation, see Webb (1954), for proteoid roots, see Purnell (1960) and Dinkelaker et al. (1995), for general chemistry, see Hegnauer (1969, 1990), for polyol distribution, see Bieleski and Briggs (2005), for pollen development, see Blackmore and Barnes (1995: Garside's Rule), for general information, see Johnson & Briggs (1963, 1975: including chromosome lengths) and Venkata Rao (1971), for nodes, Catling and Gates (1998), for a survey of seed coat anatomy, Takhtajan (2000), for pollen, see Sauquet et al. (2006) and Sauquet and Cantrill (2007), and for general information and a new classification the outlines of which are followed here, see Weston and Barker (2006) and especially Weston (2006).

Synonymy: Lepidocarpaceae Schultz Schultestein