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; shoot apical meristem complex; arbuscular mycorrhizae +; stem with ectophloic eustele, endodermis 0, xylem endarch; 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 ?; leaf vascular bundles collateral; leaves spiral, simple, axillary buds?, prophylls [including bracteoles] two, lateral; plant heterosporous, sporangia eusporangiate, on sporophylls, sporophylls aggregated in indeterminate cones/strobili; true pollen [microspores] +, mono[ana]sulcate, pollen exine and intine homogeneous, ovules unitegmic, crassinucellate, megaspore tetrad tetrahedral, only one megaspore develops, megasporangium indehiscent; male gametophyte development endo/exosporic, gametes two, with cell walls; 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, 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, numbers unstable, P not differentiated, outer members not enclosing the rest of the bud, A many, development centripetal, 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, pollen subspherical, binucleate at dispersal, trinucleate eventually, tectum continuous, endexine compact, lamellate only in the apertural regions, pollen tube elongated, with callose plugs, penetrating between cells, growth rate moderate, siphonogamy occuring, nectary 0, G free, several, ascidiate, with postgenital occlusion by secretion, few [?1] ovules/carpel, ovules marginal, anatropous, bitegmic, micropyle endostomal, integuments 2-3 cells thick, megasporocyte single, megaspore lacking sporopollenin and cuticle, chalazal, female gametophyte ?type, stylulus short, 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; pollen tectate-columellate, tectum reticulate [perforated]; 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.

PROTEALES [TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]]: ?

TROCHODENDRALES [BUXALES [GUNNERALES + CORE EUDICOTS]]: benzylisoquinoline alkaloids 0; euAP3 + TM6 genes [duplication of paleoAP3 gene: B class], mitochondrial rps2 gene lost.

BUXALES [GUNNERALES + CORE EUDICOTS]: ?

GUNNERALES + CORE EUDICOTS: Ellagic and gallic acids common, cyanogenesis via phenylalanine, isoleucine or valine pathways; micropyle?; PI-dB motif +, small deletion in the 18S ribosomal DNA common.

CORE EUDICOTS: Root apical meristem closed; flowers rather stereotyped: 5-merous, parts whorled, K and C distinct, K with 3 traces, A = 2x K, internal to the C whorl, (numerous, but then often fasciculate and/or centrifugal), pollen tricolporate, (nectary disc +), [G 5], [3] also common, compitum +, placentation axile, stigma not decurrent; endosperm nuclear; fruit dry, dehiscent, loculicidal [when a capsule]; euAP1 + euFUL + AGL79 genes [duplication of AP1/FUL or FUL-like gene], PLE + euAG [duplication of AG-like gene: C class], SEP1 + FBP6 genes [duplication of AGL2/3/4 gene].

SAXIFRAGALES [VITALES + ROSIDS]: Stipules +.

VITALES + ROSIDS: Anthers articulated [± dorsifixed, transition to filament narrow, connective thin].

ROSIDS: embryo long; genome duplication; chloroplast infA gene defunct, mitochondrial coxII.i3 intron 0.

ROSID I: Endosperm scanty.

CUCURBITALES + FAGALES [FABALES + ROSALES]: (N-fixing by root-dwelling associates [usu. the actinomycete Frankia]); tension wood +; stipules cauline; seed exotestal; embryo large.

Fabales + Rosales: ?

ROSALES Perleb  Main Tree, Synapomorphies.

(Frankia infection via intercellular penetration); (isoflavonoids, dihydroflavonols +); roots diarch [lateral roots 4-ranked]; prismatic crystals in ray cells [not Barbeyaceae, Elaeagnaceae]; (sieve element with non-dispersive protein bodies; sieve element plastids lacking starch [Rhamnaceae, Dirachmaceae?]); mucilage cells +; leaf margins with teeth; inflorescence cymose; hypanthium +, nectariferous, K valvate, C clawed, 1 apotropous ovule/carpel, micropyle endostomal, styles +, stigma dry; K and/or hypanthium persistent in fruit; (polyembryony +). - 9 families, 261 genera, 7725 species.

Stem group Rosales date to 89-88 million years before present, divergence of the crown group begins ca 76 million years before present (Wikström et al. 2001). Rosales contain ca 1.9% of eudicot diversity (Magallön et al. 1999); fossils are known from the Middle Eocene, ca 44 million years before present. Quite a diversity of butterfly larvae - especially caterpillars of "basal" groups and Lycaeninae - feed here (Fiedler 1995; Janz & Nylin 1998). Ronse De Craene (2003) suggests that loss of petals may characterise Rosales, with apparent "petals" occupying the position of stamens and their evolution allowing e.g. Rosaceae to diversify; comparing the vasculature of petals and stamens may bear on this morphological hypothesis, and whether or not it has anything to do with diversification is a separate issue. Indeed, if Rosales are sister to Fabales, they would not seem to be a notably diverse group in terms of species numbers, the more so since almost 4,000 species of Rosales are in the Ulmaceae-Urticaceae group, which lack petals.

Roots are commonly diarch in Rosaceae, but are also tetrarch, etc.; sampling elsewhere is poor, although less so in Ulmaceae and relatives, and diarch roots seem to be found throughout the order. At least Rosaceae, Rhamnaceae, Elaeagnaceae and Ulmaceae can be ectomycorrhizal (see Malloch et al. 1980; Smith and Read 1997). Tracheary members in Rosaceae commonly have pseudotori (thicekenings in pit membranes associated with plasmodesmata), while true tori occur in Rosaceae and elsewhere in the order (Jansen et al. 2007). Sieve tube plastids lacking both starch and protein inclusions are rare outside Rosales, although they occur in some parasites as well as Crassulaceae and Malpighiaceae (Behnke 1991a). For wood anatomy, esp. of Elaeagnaceae, see Jansen et al. (2000b) and Baas et al. (2001: fiber pits not bordered). A granular layer below the tectum may be a synapomorphy for the clade. Kubitzki (2004) provides a summary of the order.

In the past, Urticales (Urticaceae, Moraceae, etc.) were kept well separate from Rosaceae, largely because of the very reduced and usually wind-pollinated flowers of the former group, and the other families now included in Rosales were usually placed elsewhere yet again. Relationships within the order are yet unclear, although Rosaceae may be sister to the rest of the order (strong support: Savolainen et al. 2000a), and Ulmaceae and relatives (the old Urticales) and Rhamnaceae and relatives may form two more clades (also Thulin et al. 1998; Savolainen et al. 2000b; Richardson et al. 2000a; Sytsma et al. 2002 (position of Rosaceae, etc. uncertain): see tree below.

There is much useful information in Thulin et al. (1999).

Includes Barbeyaceae, Cannabaceae, Dirachmaceae, Elaeagnaceae, Moraceae, Rhamnaceae, Rosaceae, Ulmaceae, Urticaceae.

Synonymy: Barbeyales Takhtajan & Reveal, Elaeagnales Bromhead, Ficales Dumortier, Frangulales Wirtgen, Rhamnales Dumortier, Sanguisorbales Dumortier, Ulmales Lindley, Urticales Dumortier - Barbeyanae Reveal & Doweld, Rhamnanae Reveal (Rhamnales + Elaeagnales), Rosanae Takhtajan, Urticanae Reveal - Rosidae Takhtajan - Frangulopsida Endlicher, Rhamnopsida Brongniart, Rosopsida Batsch, Urticopsida Bartling

ROSACEAE Jussieu, nom. cons.   Back to Rosales

Triterpenes +, alkaloids 0; cork deep seated; (vessel elements with scalariform perforations); (true) and fiber tracheids +; sieve tubes with non-dispersive protein bodies; leaves spiral (opposite), usu. conduplicate, (2ndary veins palmate), stipules also often petiolar (0); inflorescences racemose; (C 0), A (1-)15-many [ca 20 common - 10 + 5 + 5, centripetal, in groups], (latrorse; pollen porate), G 1-5, free, archesporium multicellular, ovules epitropous, nucellar cap +, stigmas punctate to expanded or down style; fruit aggregate of achenes; exotestal cells periclinally elongated, radial walls thickened, or palisade or tabular, walls with spiral or reticulate thickenings, outer wall often becoming mucilaginous, (mesotesta sclerotic), endotegmic cells slightly thickened, or seed coat undistinguished; x = 7, 9; duplication of GBSSI [granule bound starch synthase I] gene.

90[list]/2520. World-wide, but esp. N. hemisphere (Map: from Vester 1940; Hultén 1971). [Photos - [Collection, Collection.]

1. Rosoideae Arnott

Herbs to shrubs; 2-pyrone-4,6dicarboxylic acid, ellagic acid +; rays often narrow; cuticle waxes as narrow ribbons and triangular rodlets; leaves compound; (epicalyx +), carpels usu. many, ovule unitegmic, (atropous); fruits achene or drupelet; x = 7; plant with phragmidiaceous rusts.

Especially temperate (to Arctic) areas.

1A. Filipendula - Plant herbaceous; receptacle enlarged, 2 ovules/carpel. - 1/10. Eurasia.

Synonymy: Ulmariaceae Gray

Rosodeae T. Eriksson, Smedmark, & M. S. Kerr (= all other Rosoideae)

1B. Rubus - Prickly scrambling shrub; receptacle enlarged; fruit an aggregate of drupelets. - 1/± 250. ± Worldwide, esp. N. temperate.

Synonymy: Chamaemoraceae Lilja

1C. Colurieae Rydberg

?

3/42: Geum (40: Kajewski 1957 for classic cytological work; Smedmark & Eriksson 2006 for development of the stylar hook). Temperate, inc. montane tropics, Chile.

[Rosa + Potentilleae] + Sanguisorbeae: ?

Rosa + Potentilleae: ?

1D. Rosa - Prickly arching shrub; 2 collateral ovules/carpel; hypanthium fleshy, urn-shaped. - 1/100-150: see Bruneau et al. (2007), Wissemann and Cox (2007) and Koopman et al. (2008) for phylogenies, relationships not easy to disentangle. N. temperate; 1/3^rd spp. in Europe.

1E. Potentilleae Sweet

(Epicalyx +), receptacle enlarged.

Within Potentilleae, Potentilla is sister to the rest, Fragariinae (see Eriksson et al. 2003). Potentilla: Style often lateral/gynobasic. Ca 500 spp. N. temperate to Arctic (montane tropics to S. temperate). Fragariinae Torrey & A. Gray: (Leaves simple); (G 1); phragmidiaceous rusts 0 (Fragaria +). 10/300: Alchemilla (270). N. temperate, esp. Europe, tropical mountains (S. temperate). This group includes some ex-Potentilla, most of which have at one time or another been segregated from that genus; I am not sure how many species are involved.

Synonymy: Potentillaceae Wilbrand, Tormentillaceae Martynov

1F. Sanguisorbeae Candolle

G 1-5; phragmidiaceous rusts 0.

Within Sanguisorbeae are two subtribes. Agrimoniinae J. Presl - 5/20: Agrimonia (15). N. Temperate, Africa. Sanguisorbineae Torrey & A. Gray - 7/360: Cliffortia (115), Acaena (100). ± Worldwide, few Indo-Malesia, tropical America.

Synonymy: Agrimoniaceae Gray, Fragariaceae Nestler, Poteriaceae Rafinesque, Sanguisorbaceae Durande

Dryadoideae + Spiraeoideae: sugar alcohol sorbitol as transport carbohydrate, cyanogenic glycosides +.

2. Dryadoideae Juel

Association with N-fixing Frankia; G 1-many, ovules straight [atropous]; fruits achenes with hairy styles.

4/19: Cercocarpus (8). W. North America, circumboreal (Dryas).

Synonymy: Cercocarpaceae J. Agardh, Dryadaceae Gray

3. Spiraeoideae C. Agardh

Plant woody; flavones +, ellagic acid 0; cuticle waxes as tubules or platelets; G <5, opposite C, 2< ovules/carpel, papillate funicular obturator +, stigma usu. wet; fruit a follicle.

3A. Lyonothamnus - Cyanogenic glycosides 0; leaves opposite, compound, stipules deciduous; G seminferior; 4-6 apical, ovules/carpel. - 1/1: Lyonothamnus floribundus. California Islands, off S. California.

3B. Niellieae Maximowicz

Cyanogenic glycosides?; ovule single, apical, apotropous (-5, pleurotropous); fruitlets hard, shiny.

2/24: Niellia (14). E. and W. North America.

Synonymy: Neilliaceae Miquel

3C. Amygdaleae Jussieu

Plant ectomycorrhizal; cork superficial; true tracheids 0; leaves conduplicate, nectaries on petiole or abaxial lamina; G 1, obturator from ovary wall; fruit a drupelet; n = 8.

1/200. Temperate and tropical montane.

For a phylogeny, see Lee and Wen (2001); the distribution and nature of calcium oxalate crystals correlate quite well with this (see Lersten & Horner 2000).

Synonymy: Amygdalaceae Marquand, Prunaceae Berchtold & J. S. Presl

Kerriodae D. Potter, S. H. Oh, & K. R. Robertson [= Osmaronieae + Kerrieae]: phragmidiaceous rusts 0.

3D. Osmaronieae Rydberg

Cork superficial; pith chambered; stipules deciduous; ovules mid-position, obturator from ovary wall, styles lateral; fruit a drupe, or septicidal, the carpels also opening adaxially [Exochorda]; n = 8.

3/9: Exochorda (4), Prinsepia (4). Central to East Asia, W. North America.

3E. Kerrieae Focke

Wart-like projections on lamina; G 1-5, ?obturator; fruit an aggregate, nut-like units, (achenes: Neviusia).

4/4. East Asia, W. North America, Alabama.

Synonymy: Coleogynaceae J. Agardh, Rhodotypaceae J. Agardh

3F. Sorbarieae Rydberg

Leaves compound (simple: Adenostoma); (G 1, Adenostoma), ovules apical; (fruit an achene: Adenostoma); phragmidiaceous rusts 0.

4/8: Spiraeanthus (4). Central to East Asia, W. North America

3G. Spiraeeae Candolle

Vestured pits +; nodes 1:1 [?all]; stipules 0; 6-8 unitegmic ovules/carpel; (fruit an achene - Holodiscus).

8/106: Spiraea (80-100). N. temperate, to Columbia, (S. and) E. Africa, West Malesia.

Synonymy: Spiraeaceae Bertuch

Pyrodeae C. S. Campbell, R. C. Evans, D. R. Morgan, & T. A. Dickinson

Plant ectomycorrhizal; flavone C-glycosides +; cork superficial [?Gillenia]; rays often narrow; colleters + [probably elsewhere]; G ± connate, adnate to base of hypanthium, opposite K or odd member abaxial, gynoecial ring primordium +, ovules basal, apotropous, (micropyle bistomal); exotesta ± thickened, often mucilaginous, mesotesta thick, sclerotic; Gymnosporangium rust common.

3H. Gillenia - Leaves compound. - 1/2. E. North America.

3I. Pyreae Baillon

N = 17; four copies of GBSSI [granule bound starch synthase I].

33/ca 1000.

Kageneckia + Lindleya

(Plant dioecious); 4-many pleurotropous ovules/carpel; Gymnosporangium rust 0.

2/5. Mexico, Peru, Chile. [Kageneckia Flower, Fruit.]

Vauquelinia - Tannin-containing cells pervasive; fruit septicidal, carpels opening adaxially (and partially abaxially as well). - 1/3. S.W. North America.

Pyrinae Dumortier

Stipules deciduous; G at leaf half inferior; hypanthium fleshy in fruit, (endocarp +).

30/1000: Sorbus (260: generic limits are difficult, with divisions for "convenience" perhaps reflecting the European origin of taxonomy), Crataegus (260, inc. Mespilus: 17 sp. in 1896, 30 years later over 1000 spp. - triploid apomictic hybrids), Cotoneaster (260: forms grafts with Crataegus!), Pyrus (75), Malus (55). [Photo - Flower]

Synonymy: Cydoniaceae Schnizlein, Lindleyaceae J. Agardh, Malaceae Small, nom. cons., Mespilaceae Schultz-Schultzenstein, Pyraceae Vest, Sorbaceae Brenner

• Rosaceae are a heterogeneous family, but they may be recognised by their often compound, stipulate and serrate leaves that are never(?) 2-ranked and are only rarely opposite. Their flowers have a valvate calyx, always free and often clearly clawed petals, usually many stamens, a well-developed nectary on the hypanthium or at the base of the stamens, and free carpels. There are often achenes or drupelets, but the whole fruit is fleshy in a variety of ways; follicles are also quite common. Cyanogenesis is common (crush the leaves of Prunus, and smell), but there is more than one pathway involved.

Turonian fossils from some 90 million years before present are assignable to this family (Crepet et al. 2004 for references); other estimates tend to give younger ages (stem group ca 76 million years before present, crown group divergence [Rosoideae not included] 47-46 million years before present - Wikström et al. 2001). The inferior-ovaried clade of Pyreae seems to represent a rapid but ancient radiation (Campbell et al. 2007). For the relationship between polyploidy and diversification in Rosaceae - perhaps direct - see Vamosi and Dickinson (2006). Apomixis is quite common, as in Alchemilla (Rosoideae) and Amelanchia, Cotoneaster and Crataegus (Spiraeaoideae-Pyrodeae). In the latter genus, there were some 17 species recognised in North America in 1896, and 30 years later there were over 1000 species - C. S. Sargent described many of these. Hybridisation occurs there, and the hybrids are triploid and apomictic; in general, apomixis seems to have preceded hybridisation (Dickinson et al. 2007).

Although Rosoideae and a number of clades within it, Spiraeaoideae, Spiraeoideae minus Lyonothamnus, Pyrodeae + Sorbarieae and Pyrodeae are all well-supported clades, little can yet be said of larger patterns of relationship in the rest of the family (e.g. Morgan et al. 1994; Potter et al. 2002; Potter 2003; Potter et al. 2007). The position of Dryadoideae is uncertain, other than being a rather "basal" branch in the tree (Potter et al. 2002: Evans et al. 2002), hence perhaps the lack of obturators. Potter (2003) found that Dryadoideae were fairly well supported as sister to remaining Rosaceae in a analysis using several genes, but their position was still not secure in Potter et al. (2007), although a sister group relationships with Spiraeaoideae is indeed perhaps most likely. See Eriksson et al. (2003) for a phylogeny of Rosoideae; Alchelmilla, Fragaria, and other genera form a well-supported clade outside Potentilla. Filipendula is sister to other Rosoideae. "Intergeneric" hybridisation seems to occur (Smedmark et al. 2003). Aldasoro et al. (2005) suggest morphological and biogeographic relationships in the inferior-ovaried Spiraeaoideae-Pyreae. Exochorda forms a small clade along with Oemleria and Prinsepia (Evans & Dickinson 1999a for information); they have been placed near Prunus (Potter et al. 2002, see also Lee & Wen 2001) to which they do show some morphological similarity. Amygdaleae are circumscribed narrowly here (one genus!), following Potter et al. (2002, 2006). In the recent past Maddenia (dioecious, K 10, C 0) has also been placed near Prunus. Generic limits in Pyreae are difficult, there being little molecular divergence between many of them (but considerable divergence within them (Dickinson et al. 2007; Lo et al. 2007, esp. Crataegus s.l.).

Fruit types are certainly not as good indicators of relationships as was for a long time thought, but chemistry, chromosomes, and fungi all support the molecular realignments (see esp. Morgan et al. 1994), as does developmental work by Evans and Dickinson (1999a, b, 2002). Thus the old Spiraeoideae include a considerable amount of variation and are strongly paraphyletic (they include the old Prunoideae/Amygdaloideae and Maloideae), although in the past they had been considered a very natural group (e.g. Kalkman 1988); however, tribes in the Spiraeaoideae may represent clades (see esp. Evans et al. 2002; Potter et al. 2006). As is common, optimisation of characters on the tree presents problems. Potter et al. (2007) used DELTRAN, and as a result being host to Gymnosporangium rusts is not an apomorphy of their Pyrodeae; using ACCTRAN (as here) it is. Along the same lines, they reasonably divided up the presence of sorbitol into two states; it might be present in only small amounts (Dryadoideae), or it was more abundant (Spiraeaoideae).

Savile (1979b) discusses the distribution of phragmidiaceous rusts within Rosaceae-Rosoideae; they occcur on no other Rosaceae, and only rarely on plants from other families. The telial stage of Gymnosporangium rusts is common on some Cupressaceae, the aecial stage is found on Rosaceae-Pyrodeae. Rosaceae rarely produce phytoalexins (Harborne 1999).

A polyderm is common, although perhaps not occuring in Pyreae (Mylius 1913). 1:1 nodes occur in Spiraea, a genus that also lacks stipules, although normally Rosaceae have stipulate leaves and 3:3 nodes. This correlation between stipule presence/absence and nodal vasculature is fairly general in eudicots, and so it is interesting that it is evident within Rosaceae, as was early noted by Sinnott and Bailey (1914). There are extensive data on cuticle waxes in the family (Fehrenbach & Barthlott 1988), but they are recorded only as summaries in the context of conventional subfamilies; Barthlott (pers. comm.) kindly provided a more detailed breakdown. The epicalyx seems to represent stipules associated with the calyx members. There are often five traces to each carpel. Rhodotypos has a protruding nucellus (cf. Rhamnaceae). Chamaebatia (Dryadoideae): G 1, ovule single, basal, no obturator (Evans & Dickinson 2002a). The lignified exotesta can be found even in the drupe of Prunus.

Species of different genera of Rosaceae, one N-fixing (Cowania - Dryadoideae) and the other (Fallugia - Rosoideae-Colurieae) not, can form successful grafts, but when the non-N-fixing genus is the stock it will still not fix nitrogen (Kyle et al. 1986). Even in taxa with inferior ovaries, there is great variation in whether or not the carpels are connate, or what parts are connate, and in whether or not the carpels are adnate to the hypanthium. Thus Cotoneaster, which will form grafts with Crataegus, has an inferior ovary yet more or less separate carpels, cf. also Pyracantha. Indeed, the odd genus Dichotomanthes, also included in Pyreae, has a single carpel that is superior in position (Rohrer et al. 1994); its distinctive gynoecial morphology must represent a reversal.

Although Rosaceae as described above are holding together very well despite their morphological heterogeneity, there have been departures. Chrysobalanaceae, often associated with Rosaceae in the past, are part of a distinct clade within Malpighiales, Quillaja rather unexpectedly is an isolated monotypic clade within Fabales, while recently (Oh & Potter 2006) Guamatela has been found to be a correspondingly isolated clade in Crossosomatales.

The diploid Gillenia is sister to the Pyreae (Potter et al. 2002; Evans & Dickinson 2002). It has long been suspected that Pyreae are of wide hybrid origin, as their chromosome number might suggest (9 [Rosoideae] x 7 [Spiraeaoideae] = 16 [some Maloideae]), see Evans et al. (1998), however, Evans and Campbell (2002) suggest that this is unlikely. Polyploidisation with subsequent aneuploidy (9 + 9 = 18, 18 - 1 = 17) of Gillenia (herbaceous, with compound leaves!) or something similar is more likely. Note that Gillenia is host to the same rusts that are found on other Pyrodeae, but it has only two copies of GBSSI, as is the condition in the rest of the family.

Some general information is taken from Robertson (1974) and Kalkman (2004), Judd et al. (2002), and especially Potter et al. (2007), while there is information on carpel orientation and general morphology in Focke (1888), Sterling (1969 and references), Kania (1973) and Weberling (1989), androecial diversity is discussed in Lindenhofer and Weber (2000 and references), rust hosts in Savile (1979), cork initiation and bark anatomy in Lotova and Timonin (e.g. 1998, 1999, 2002) and also Weiss (1890), general chemistry in Hegnauer (1973, 1990), 2-pyrone-4,6dicarboxylic acid distribution in Wilkes and Glasl (2001), tannins in Okuda et al. (1992), exotesta in Frohne and Jensen (1992), wood anatomy in Zhang (1992), and floral development in Evans and Dickinson (1999a, 1999b, 2002); for information on Vauquelinia, see Hess and Henrickson (1987).

[Barbeyaceae + Dirachmaceae + Rhamnaceae + Elaeagnaceae] [Ulmaceae [Cannabaceae [Moraceae + Urticaceae]]]: trans-spliced intron in nad1 gene [cis-spicing elsewhere].

Diversification in this clade (Rhamnaceae sister to the rest) begins 64-62 million years before present (Wikström et al. 2001).

For nad1 intron splicing, see Qiu et al. (1998). For polyembryony, at least sporadic in the clade, see G. Dahlgren (1991).

Barbeyaceae + Dirachmaceae + Rhamnaceae + Elaeagnaceae: petiole bundle arcuate.

This grouping is suggested by Campbell (pers. comm.) and Sytsma et al. (2002: support weak). Rhamnaceae, Barbeyaceae and Dirachmaceae may form a clade (Richardson et al. 2000a). Dense, curly hairs on the abaxial surface of the leaf blade could be a synapomorphy for this group (Sytsma et al. 2002); Qiu et al. (1998) put this feature at the next higher node. A granular layer below the tectum is found in both Rhamnaceae and Dirachmaceae - elsewhere?

BARBEYACEAE Rendle, nom. cons.   Back to Rosales

Trees; ellagic acid +; libriform fibers +; nodes 1:1; mucilage cells?; stomata paracytic; hairs unicellular, spirally twisted, leaves opposite, supervolute-curved, margins entire, stipules 0; plant dioecious, inflorescence fasciculate, bracts and bracteoles 0; hypanthium and nectary 0, P 3-4, A (6-)9-12, connective produced, tectum granulate, G 1-2(-3), ± separate, ovule subapical, epitropous, ?unitegmic, style branches and stigmas long, ?type; fruit a nutlet, P accrescent; seed coat undistinguished, exotesta perforated, endotegmen tanniniferous; n = ?

1[list]/1: Barbeya oleoides. N.E. Africa, Arabia (Map: from Aubréville 1974).

• Barbeyaceae may be recognised by their opposite, entire, exstipulate leaves with dense white indumentum on the undersurface and their shortly pedunculate, axillary, cymose inflorescences. The flowers are small, wind-pollinated and with a uniseriate perianth and the nutlets are enveloped by the accrescent perianth.

Are the petals clawed? The sieve tubes have compound perforations, unlike Ulmaceae and its immediate relatives and other Rosales. The monotypic Barbeyales were placed in Hamamelididae-Barbeyanae by Takhtajan (1997).

Additional information is taken from Dickison and Sweitzer (1970: morphology), Tobe and Takahashi (1990: hairs and pollen), Friis (1993: general), and Bouman and Boesewinkel (1997: ovule and seed); Hegnauer (1990) has a little information on chemistry.

Dirachmaceae + Rhamnaceae + Elaeagnaceae: A = and opposite C/alternate with P, capsule septicidal; coat multiplicative, exotesta palisade, thick-walled; cotyledons large.

DIRACHMACEAE Hutchinson   Back to Rosales

Shrub; stalked glands +/0; chemistry?; cork ?; phloem stratified; nodes ?lacunar; leaves spiral, stipules subulate, persistent; flowers single, terminal, 5-8-merous; epicalyx of 4-8 lobes, C contorted, nectaries on base or on subbasal appendages, lacking stomata, A extrorse, anthers long, opening from apex, G [8], lobed, opposite the K, style +, stigma clavate or punctate, ?type; fruit beaked, segments opening adaxially, wooly inside, with columella, K deciduous above the hypanthium; seeds laterally flattened, median integumentary antiraphe bundle +; endosperm?, embryo color?; n = ?

1/2. Socotra, Somalia (Map: from Link 1991b).

• Dirachmaceae are shrubs that may be recognised by their small, strongly-toothed leaves which have subulate stipules; the latter persist along the stem. The flowers have an epicalyx and are relatively large, and the stamens are opposite the petals and have extrorse anthers that clearly open from the top downwards. The capsules are densely wooly inside.

The single flowers may represent a reduced, cymose inflorescence. A "hypanthium" is described as developing between the sepals and petals; there is also an ordinary hypanthium. Petal initiation is later than that of the stamens, and until quite late in development the petals are much shorter than the stamens. There is a structure described as a small, funicular aril, perhaps similar to that found in some Rhamnaceae (Ronse De Craene & Miller 2004).

The exotestal seeds with straight embryos suggest that Dirachma is not close to Geraniaceae (Geraniales), with which Dirachma had been linked (Boesewinkel 1985), and a position here seems best.

For information, see Link (1991b, cf. 1994), Baas et al. (2001: wood anatomy is particularly similar to that of Rhamnaceae), Bayer (2004) and Ronse De Craene and Miller (2004: floral development).

RHAMNACEAE Jussieu, nom. cons.   Back to Rosales

Woody (lianes; herbs; tendrillate; leaves much reduced and whole plant thorny); chelidonic acid +; saponins, biflavonyls, benzylisoquinoline alkaloids, (roots with N-fixing Frankia) +, myricetin, ellagic acid 0; (vessel elements with scalariform perforations); libriform fibers +; lysigenous mucilage cavities +; leaves opposite or spiral, conduplicate(-plicate) or involute, (margins entire; 2ndary veins palmate), stipules also petiolar [Colletia] (0), colleters +; (plant dioecious); flowers small, 4-5(-6)-merous; hypanthium +, to long and tubular, K (connate), longitudinally ridged adaxially, C cucullate (0), enfolding A, (nectary as disc; on ovary), G [2-3(-5)] to inferior, opposite K or odd member adaxial, ovules (2; median) epitropous or apotropous, archesporium often multicellular, nucellar cap +, nucellus ± protruding, hypostase +, style + or styles separate; fruit a drupe or also partly loculicidal capsule, (samara; schizocarp), K often deciduous; seeds often laterally flattened, (arillate), median integumentary antiraphe bundle +, (mesotesta with a few sclerotic cells), endotegmen of cuboid cells, with scalariform thickenings (slightly lignified); endosperm +/0, (starchy), polyembryony common, embryo green; n = (6, 8-)12 (13).

52[list]/925: Phylica (150), Rhamnus (125), Zizyphus (100-170, paraphyletic, see Islam & Simmons 2006), Ceanothus (55), Gouania (50). World-wide, especially tropics and warm temperate regions (Map: see van Steenis & van Balgooy 1966; Meusel et al. 1978). [Photo - Flower] [Photo - Dry fruit] [Photo - Fleshy fruit]

• Rhamnaceae are recognisable by their toothed, stipulate leaves that often have strong, parallel secondary veins and scalariform tertiary venation. Their flowers have stamens opposite the often clawed petals, a hypanthium with a nectary inside, and a valvate calyx with sepals that are ridged down the middle on their inner surfaces. The capsules are rather similar to those of Euphorbiaceae, the pericarp often separating into two layers and the endocarp twisting as dehiscence occurs. However, since the seeds are basal, there is usually no columella, while towards the base of the fruit there is often a conspicuous ring marking the place where the hypanthium was attached. In taxa such as Gouania with largely inferior ovaries the calyx, etc., is persistent. In lianes the shoots often develop somewhat laterally in the leaf axils and may have a bud at the very base.

Fossils from the Cretaceous-Cenomanian, some 94 million years before present, have been identified as members of this family (Crepet et al. 2004 for references; Calvillo-Canadell & Cevallos-Ferriz 2007 for Mexican fossils from the late Campanian onwards). However, Wikström et al. (2001), followed by Richardson et al. (2004), date stem Rhamnaceae to some 64-62 million years before present. Richardson et al. (2004, see also Richardson et al. 2001a) discuss the diversification of the family in detail, noting i.a. the rapid diversification of the speciose Phylica within the last ca 8 my.

Ceanothus has N-fixing actinomycetes, as do many Colletieae; together they form a monophyletic group (Richardson et al. 2000b). Ectomycorrhizae have been reported from Rhamnus and Pomaderris (Malloch et al. 1980). Quite a few species are xeromorphic. New World species of Gouania have glands at the base of the lamina; Karwinskia has pellucid dots in the leaves.

There are three main clades in the family, the rhamnoids, which include Maesops and Ventilago (three tribes), the ziziphoids (five tribes), which include most of the rest of the family (for the Pomaderreae, one of these tribes, see Kellermann et al. 2005 and Kellermann & Udovicic 2008), and the ampeloziziphoids (three tribes: three genera: four species).

General information is taken from Brizicky (1964) and Medan and Schirarend (2004); Vikhireva (1952: not read) described fruit anatomy, Hegnauer (1973, 1990) summarised chemistry, Richardson et al. (2000a, b) present a phylogeny and a classification based on it, Medan (1988) discussed gynoecial development, Medan and Aagesen (1995) comparative floral and fruit morphology, and Richardson et al. (2004) historical biogeography.

Synonymy: Frangulaceae de Candolle, Gouaniaceae Rafinesque, Phylicaceae J. Agardh, Ziziphaceae Adanson

ELAEAGNACEAE Jussieu, nom. cons.   Back to Rosales

Trees or shrubs; roots with N-fixing Frankia; dihydroflavonols?, 0-methyl flavonoids, ellagic acid +, myricetin 0; hairs lepidote or stellate; cambium storied; phloem stratified; pits vestured; true and fiber tracheids +; fiber pits bordered; wood with broad rays; sieve tubes with non-dispersive protein bodies; nodes 1:1; petiole bundles arcuate or annular; mucilage cells?; leaves spiral or opposite, conduplicate-flat, entire, stipules 0; (plant dioecious); inflorescence a raceme, or flowers axillary, (2-)4(-6)-merous, hypanthium long, C 0, A also 2 x P, borne in throat of tube, pollen 3-nucleate, G 1, ovule micropyle?, with funicular obturator, archesporium multicellular, style long, stigma decurrent or capitate; hypanthium accrescent and fleshy in fruit [an anthocarp!]; pericarp thin [Hippophae]; testa very thick, exotesta with sinuous anticlinal walls at least in part (not palisade), mesotesta ± thick-walled; endosperm with chalazal haustorium, (starchy); n = 6, 10, 11, 13, 14.

3[list]/45: Elaeagnus (20-45). North Temperate, warm tropical; Malesia and Australia - also quite widely cultivated and/or escaped (map: from Meusel et al. 1978; Hultén & Fries 1986). [Photos - Collection] [Photo - Shepherdia Fruit © R. Kowal]

• Elaeagnaceae are often thorny and mostly deciduous shrubs that are recognisable by their exstipulate leaves with entire margins; the whole plant is densely covered with scaly-stellate indumentum, which often gives it a greyish or silvery appearance. The hypanthium is relatively long and there is no corolla. The dry fruit proper is surrounded by the fleshy hypanthium (cf. some Nyctaginaceae), and so the result is very like a berry or drupe.

All genera are associated with N-fixing Frankia.

The androecium is obdiplostemonous according to Huber (1963). Seed anatomy is rather like that of Rhamnaceae (Corner 1976); Harrison and Beveridge (2002) have clarified fruit and seed anatomy of Hippophae.

Elaeagnaceae have been difficult to place. They were included in Proteales by Cronquist (1981) because of superficial floral similarities, and in Elaeagnales - Rhamnanae, next to Proteanae, in Rosidae, by Takhtajan (1997).

For rust host preferences, see Savile (1979), for general information, Bartish and Swenson (2004).

Synonymy: Hippophaeaceae G. Meyer

Ulmaceae [Cannabaceae [Moraceae + Urticaceae]]: flavonols and their glycosides, myricetin [some Ulmaceae, Cannabaceae] +, ellagic acid 0; plant with ± watery exudate; hairs unicellular and multicellular-glandular; cambium ± storied; libriform fibers +; phloem stratified; sieve tubes with non-dispersive protein bodies (some Cannabaceae - 0); cystoliths [globose; usu. CaCO₃] and epidermal and hair cell wall silicification and calcification common; leaf with 2ndary veins proceeding straight to non-glandular teeth and higher-order veins convergent on those teeth [urticoid], at least one prominent prophyllar bud; stipules cauline; flowers small, hypanthium?, C 0, A = and opposite P, pollen porate, granular layer below tectum +, nectary 0, G [2], abaxial only fertile, ovule epitropous, apical, stigmas sessile, spreading, receptive area extending down adaxial surface and ± confluent; fruit a drupe; endosperm scanty; polyembryony common, testa perforated [rare in Ulmaceae]; x = 14, centromeres both median and subterminal.

This clade may be some 67-65 million years old, Ulmaceae diverging 57-55 million years before present, the rest ca 48-42 million years before present (Wikström et al. 2001). Some nymphalid butterfly groups have larvae on members of these families (see also under Urticaceae) - but also on the immediately unrelated Euphorbiaceae (Malpighiales: see Ehrlich & Raven 1964). Similarly, caterpillars of Acraea are found quite commonly on Urticaceae (including Cecropia), but also on Moraceae, etc.; this particular genus is also particularly common on Passifloraceae and their relatives.

Raffinose and stachyose are common oligosaccharides in phloem exudate in Ulmaceae, Moraceae and Cannabaceae sampled (Zimmermann & Ziegler 1975). The group has homogeneous wood anatomy: Rays are relatively broad, pits are simple, intervessel pitting is alternate, fibers are septate, and parenchyma is paratracheal (Baas et al. 2000). Furthermore, at least some members (Celtis, Ulmus) have a torus-bearing, pit membrane (Coleman et al. 2004) that is only weakly lignified. Two-ranked leaves may be an additional synapomorphy for the group (or pegged at a still higher level), as well as urticoid teeth. Because of the well-developed prophyllar bud(s), the inflorescences are often paired, with a bud between them, and/or the branches may have a bud on one or both sides at the base; Ulmus does not show this arrangement. The "stipular buds" of Cannabis (Miller 1970 and references) are really prophyllar buds. It is not clear which taxa have a hypanthium; at least some species of Ulmus and Pilea do, but other species of Ulmus, Zelkova and Trema show no obvious signs of one (see also Bechtel 1921). Staedler (1923) discusses the absence of an anther epidermis in the group (but not in Ficus; situation in other Rosales?); there is no obvious link with dehiscence mechanism. Starchy pollen is common, but apparently not in Urticaceae. Bechtel (1921) and Eckardt (1937) described gynoecial morphology in considerable detail. The copious information on the four families awaits synthesis, although this process has been begun by Sytsma et al. (2002); this paper should be consulted for details of character evolution. Sytsma et al. (2002) note that inflexed stamens and their dehiscence, fruit type, and laticifers need further detailed study within this clade; but hypanthium presence and other characters can be added to this list!

The phylogenies suggested by Sytsma et al. (2000) and Song et al. (2001) place Cannabaceae within Celtidaceae (see also e.g. Ueda et al. 1997b; note that Cannabaceae is the earliest name for the combined group) and Cecropiaceae within Urticaceae, and this set of relationships has been strongly supported by a recent, more comprehensive analysis (Sytsma 2002). The group as a whole is very well characterised, and it still may make sense to expand Urticaceae, as, for instance, Corner (1952) did when he placed Moraceae in Urticaceae.

For further information, see Satake (1931: spodograms), Sweitzer (1971: anatomy), Giannasi (1978, 1986: chemistry), Behnke and Barthlott (1983: hairs), Takaso and Tobe (1990: testa), Omoron and Terabayashi (1991: phylogeny), Terabayashi (1991: vernation), Hennig et al. (1994: cuticle waxes), Judd et al. (1994: morphological phylogeny), Tobe and Takaso (1996: hairs), and Zavada and Kim (1996: phylogeny).

ULMACEAE Mirbel, nom. cons.   Back to Rosales

Trees; lignans, sesquiterpene lactones +; (wood fluoresces); unicellular hairs smooth; sieve tube plastids often with protein crystalloids; cystoliths usu. pegless; leaves 2-ranked, laterally (vertically) conduplicate-plicate, 2ndary veins going into teeth, stipules extrapetiolar; flowers perfect and mixed; P spiral (connate), pollen 4-7-porate, exine rugulose, (micropyle bistomal), at least one stigma with 3(-5) vascular bundles; fruit also a samara; seeds flattened, coat undistinguished, exotestal cells elongated, unthickened; (embryo curved - Zelkova); often terminal/subterminal diffuse-complex centromeres; 69bp ndhF deletion.

6[list]/35: Ulmus (20-30, species limits uncertain). Mostly N. temperate, esp. Asian, but scattered elsewhere except Australia and the Pacific (Map: from Soepadmo 1977; Hultén & Fries 1986; Fl. N. Am. III 1997, incomplete). [Photos - Collection]

• Ulmaceae are usually trees and may be recognised by their usually 2-ranked, strongly serrate, stipulate leaves with asymmetrical bases; the pinnate secondary veins proceed to the apex of the teeth (not in Ampelocera). At least some of the small flowers are perfect and the fruits are flattened.

Ulmus lacks well-developed prophyllar buds and has one of the two stipules intrapetiolar, they are both intrapetiolar in seedlings of some species, and the leaves may also be opposite, as in seedlings. Hemiptelea has pegged cystoliths. The breeding system in the family is variable, but at least some flowers are perfect. Nawaschin (1895) suggested that chalazogamy occured in Ulmus. Holoptelea has a thick-walled exotesta.

The poorly-known Ampelocera was included here by Ueda et al. (1997b); although its hairs are smooth, its leaves have ascending veins (see also Wiegrefe et al. 1998).

For chemistry, see Hegnauer (1973, 1990), for testa anatomy, see Takaso and Tobe (1990), for general information, see Todzia (1993).

Cannabaceae [Moraceae + Urticaceae]: C-glycoflavones also +; (sieve tube plastids with starch grains); unicellular hairs usu. micropapillate; 2ndary veins palmate; stipules cauline-intrapetiolar; flowers imperfect; embryo curved.

CANNABACEAE Martynov, nom. cons.   Back to Rosales

Trees or ± herbaceous, erect or twining; true tracheids +; cystoliths usu. with pegs [distribution?]; leaves (spiral; opposite), (laterally) conduplicate-plicate (conduplicate; supervolute; strongly palmately lobed or compound, veins proceeding to the apex of lobes - Cannabis, Humulus), 2ndary veins ascending, stipules connate or not; pollen with 2-3(-5) pores, exine scabrate to verrucate, micropyle bistomal, stigmas with single vascular bundle; (fruit an achene); seeds globose, exotestal cells tangentially elongated, with arms, unthickened; endosperm +, embryo also coiled; (n = 8-11, 13, 15), centromeres medial/submedial, simple.

11[list]/170: Celtis (ca 100). Worldwide, but not Arctic, distribution of Humulus lupulus in Aa sia is unclear (Map: from Wickens 1976; Soepadmo 1977; Hultén & Fries 1986; George 1989; Fl. N. Am. III 1997). [Photos - Collection] [Photo - Celtis Flower]

• Cannabaceae may be recognised by their 2-ranked, serrate leaves with ascending veins that do not proceed straight into the teeth, more or less intrapetiolar stipules, and prominent prophyllar buds. The fruit is a rounded drupe. However, Humulus and Cannabis have opposite and spiral leaves respectively, secondary veins running into the teeth, and Humulus lacks buds at the base of the staminate inflorescence...

The "distinctive" camptodromous (to semicraspedodromus) venation of Celtidaceae s. str. is disturbed both by the inclusion of Cannabis, etc., in this clade, but also by the occurence of strictly craspedodromous venation in Palaeocene Celtis (Manchester et al. 2002).

Parasponia is the only non-legume nitrogen fixer that is associated with other than actinomycetes, its rhizobia remain in infection threads.

Whether the laticifers of Cannabis etc., are really similar to those of Urticaceae and Moraceae must be confirmed; there is no milky exudate and they occur throughout the plant. Only the "basal" Aphananthe and Gironniera have flavonols. Lozanella, with its opposite leaves and boxy venation, looks rather like Urticaceae, but it has a bilobed stigma. The anticlinal walls of the testa of Humulus are sinuous and its embryo is green. n = 10 is common in Cannabaceae. Cannabis and Humulus have an X-autosome balance system determining the 'sex' of the plant.

Pteroceltis, Humulus, and Cannabis are close, and they and some other members of this clade have sieve tube plastids with starch grains (Behnke 1989). Lozanella is sister to Aphananthe or sister to the rest of the family (Wiegrefe et al. 1998; Soltis et al. 2002).

For general information, see Grudzinskaya (1967), Mohan Ram and Nath (1964), Todzia (1993: as Ulmaceae), and Kubitzki (1993b: as Cannabaceae), for chemistry, see Hegnauer (1973, 1990, as Ulmaceae; also 1964, 1989).

Synonymy: Celtidaceae Link, Lupulaceae Link

Moraceae + Urticaceae: latex system +; (2ndary veins pinnate); stamens incurved in bud; polyembryony 0.

There is a group of genera of Moraceae with explosive pollen dispersal, and it now appears that inflexed stamens are a synapomorphy for Moraceae + Urticaceae (Datwyler & Weiblen 2004). The moraceous genera with such stamens are in the paraphyletic Moreae that is part of a basal polychotomy within Moraceae. Indeed, the straightening stamens and reflexing tepals of Morus alba show the fastest movement of any plant parts known, over half the speed of sound (Taylor et al. 2006)!

Scattered in the group are taxa in which the tepals are persistent (e.g. Pilea) or accrescent (e.g. Morus, i.e. the fruits are anthocarps.

MORACEAE Link, nom. cons.   Back to Rosales

Largely woody; (isoflavonoids +); (cork in outer cortex); laticifers throughout the plant, latex milky; (stomata aniso- and cyclocytic); leaves spiral (opposite), ptyxis variable, stipule also ensheathing stem [open in leaf axil - Ficus], (0 - Fatoua); dicoecious [plesiomorphous], inflorescence congested-spicate (axis expanded); P (0-)5(-10), connate basally; (stamens straight), (G inferior), (ovule subapical; campylotropous), styles 1 or 2, often unequal; fruits a drupe or achene, receptacle often accrescent; seed coat undistinguished (several thickened layers - Prainea); (endosperm +); (n = 12 upwards, esp. 13, 14, variation great in Dorstenia), both terminal and median centromeres.

38[list]/1100: Ficus (750: infl. axis concave), Dorstenia (105: infl. axis spreading, fruit a dehiscent drupe), Artocarpus (50: infl. elongated, bread and jack fruits - up to 50 kg), Antiaropsis (infl. axis concave at first, but spreading ["dehiscing"] when ripe). Mostly tropical to warm temperate (Map: from Jalas & Suominen 1976; George 1989; Fl. N. Am. III 1997). [Photo - Inflorescence, Fruit, Fruit, Fruit]

• Moraceae are laticiferous plants with stipulate leaves and often boxy fine venation; the flowers are small and densely aggregated; the inflorescence axis is often large, becoming much accrescent and ± fleshy in fruit.

Berg (2005) suggests that diversification in Moraceae occured on a still physically coherent tropical supercontinent. Zerega et al. (2005) advance a more complex hypothesis to explain the distribution and diversification of the family; they date its diversification to at least 79 million years before present, and the divergence of the clade to at least 89 million years before present. Bombyx mori (the silkworm) caterpillars can eat quite widely within Moraceae, but not on most other members of the Ulmaceae group - although they will grow on Ulmus itself (Fraenkel 1959). Caterpillars of danaine butterflies quite commonly use Moraceae as food plants; both they and their usually preferred Apocynaceae are rich in latex, although Moraceae do not often have cardenolides (Ackery & Vane-Wright 1984).

Ficeae are sister to Castilleae (plus some errant Artocarpeae), and both have urceolate inflorescences and insect pollinators breeding among the flowers (Datwyler et al. 2003; Datwyler & Weiblen 2004). The intimate and remarkable association between figs and their agaonid fig-wasp pollinators, and the parasites of those pollinators, is well known (Lopez-Vaamonde et al. 2001; Jousselin et al. 2003; Jackson 2004a; Rønsted et al. 2005b for references); the beginning of the association/co-divergence dates to 100-60 million years before present. Wasps that parasitise the fig wasps may be of considerable importance in preserving the mutualism betweem agaonid and fig (Dunn et al. 2008; for information on figs and wasps, see also the papers in Symbiosis 45, nos 1-3, 2008). Also involved are wasps that cannot pollinate, and drosophilid flies that in Africa, at least, have a very close association with figs and oviposit either on the stomium or the exit holes made by the male fig wasps (Harry et al. 1996, 1998). Figs of course have a variety of growth forms, from stranglers to lianes to small shrubs to large trees, and also provide a very important source of food for tropical frugivores (Compton 1996 [a whole series of papers]; Shanahan et al. 2001; Harrison 2005).

Laticiferous cells elongate and branch and intrude between other cells, the nuclei divide, but cell walls are not formed.

The paraphyletic Moreae with their incurved stamens include Morus (fleshy perianth + drupe, a syncarp), Maclura (ditto), and Broussonetia (drupe - tapa cloth). Dorstenia, etc., also have drupes (and incurved stamens); the stone is shot out of the turgid mesocarp, the separation following a line of weakness in the tissue. Some species of Dorstenia have small, cauline stipules that do not overlap the petiole.

Some information is taken from Rohwer (1993a); for chemistry, see Hegnauer (1969, 1990); for pollen, see Burn and Mayle (2008); chromosomes, see Oginuma and Tobe (1995); and for phylogeny, see Datwyler et al. (2003) and Datwyler and Weiblen (2004).

Synonymy: Artocarpaceae Dumortier, Dorsteniaceae Chevalier, Ficaceae (Berchtold & J. Presl) Dumortier

URTICACEAE Jussieu, nom. cons.   Back to Rosales

(Sub)herbaceous (shrubs or trees; lianes); dihydroflavonols?, (furanocoumarins) +; cork cortical [Urtica]); (wood fluoresces); laticifers in bark only, latex 0 (milky); petiole bundle(s) annular or arcuate; cystoliths often elongated (0); (stomata aniso- and paracytic); leaves 2-ranked or spiral, (deeply lobed or compound - Cecropia and relatives), base often asymmetrical, stipule also intrapetiolar or sheathing [open on stem opposite leaf] (0 - Soleirolia); (plant dioecious); P (1-)4, 5(-6), valvate, (connate), staminate flowers: filaments explosively straightening, (not explosive - Poikilospermum; straight - Cecropia), endothecium 0, pistillode +; carpellate flower: staminodes +, G pseudomonomerous, ovule basal, ± straight [atropous], style 1, or stigma sessile, penicillate; fruit also often a nut or achene; seed coat perforated, ± crushed, but various testal/tegmic layers persisting; (endosperm +; starchy), embryo straight, (cotyledons thick, radicle short - Pouruma, Myrianthus); n = 7-14 [x = 14 is unlikely to be basal], protein bodies in nuclei.

54[list]/2625: Pilea (500-600: achenes dispersed by straightening of inflexed filaments of staminodes; see Monro 2006 for suggestions as to how to proceed with the phylogenetic analysis of the genus), Elatostema (300: Hadiah et al. 2003), Urtica (80), Cecropia (75), Coussapoa (50). World-wide, but mainly tropical (Map: from Hultén & Fries 1986; George 1989; Fl. N. Am. III 1997). [Photo - Shoot, Flower, Fruit.]

• Urticaceae are variable in habit but have stipulate leaves with boxy venation. The small flowers are borne in branched, clearly cymose inflorescences - carpellate inflorescences may be capitate - and the anthers are often explosively dehiscent. Some genera related to Cecropia are trees with stout stems, deeply lobed or compound leaves, densely spicate inflorescences, and stamens that are not explosive.

It has been suggested that caterpillars of Nymphalini butterflies have a plesiomorphic association with Urticaceae as food plants (Janz et al. 2001); caterpillars in a clade of Nymphalidae-Heliconiinae-Acraeini utilise members of this family, probably switching from host plants in the Passifloraceae area (Silva-Brandão et al. 2008). Cecropia is a fast-growing pioneer tree that is associated with Azteca and some other ants that live in the stems and eat glycogen-rich food bodies (Müllerian bodies) produced by the plant at the abaxial base of the petiole; beetles may eat these food bodies, ant eggs, etc. (Jolivet 1991; Longino 1991; Yu & Davidson 1997). This association may break down, especially on islands and at high altitudes (Janzen 1973); Musanga, e.g. M. cecropioides, from Africa, also lacks ants but is otherwise very similar to Cecropia. (Species of Macaranga (Euphorbiaceae) are ecological analogues of Cecropia in Malesian forests.)

Groups of cells in the vascular tissue may be unlignified and the pericyclic sheath may also be late in lignifying. Boehmeria has a fleshy perianth. For the absence of an endothecium, see Staedtler (1923); this character needs more extensive sampling in the context of recent phylogenies. The gynoecium is basically bicarpellate, but one carpel appears to be highly reduced (Eckardt 1937). Shamrov (2004) shows the inner integument of Leucosyke becoming much elaborated and functioning as an obturator. The seeds of Dendrocnide may lack holes in the exotesta, and the whole seed coat is relatively well developed, while Kravtsova (2006) found ingrowths in cell walls of both the pericarp and seed coat, observations that should be extended.

Urticaceae minus Cecropiaceae are paraphyletic (Sytsma et al. 2000, 2002 - three genes; Monro 2006 - two genes); the latter are polyphyletic and heterogeneous. However, Datwyler & Weiblen (2004 - one gene) and Zerega et al. (2005) find the reverse relationship, and strong support for Poikilospermum as sister to the rest of the family - [Poikilospermum [Cecropiaceae s. str. [rest of Urticaceae]]]. Either way, Cecropiaceae are best included in Urticaceae; their cystoliths may be circular, or they may be absent.

See Bigalke (1933: cystoliths and hairs), Miller (1971: general), Hegnauer (1973, 1990: chemistry), Berg (1978), Kubitzki (1993b: general), Friis (1993: general) and Kravtsova (2003: seed coat anatomy) for additional information.

Synonymy: Cecropiaceae C. C. Berg