Extra-gynoecial pollen-tube growth in apocarpous angiosperms is phylogenetically widespread and probably adaptive

? Fusion of floral carpels (syncarpy) in angiosperms is thought to have allowed for significant improvements in offspring quantity and quality in syncarpous species over gymnosperms and apocarpous (free-carpelled) angiosperms. Given the disadvantages of apocarpy, it remains an evolutionary puzzle why many angiosperm lineages with free carpels (apocarpy) have been so successful and why some lineages show reversals to apocarpy. ? To investigate whether some advantages of syncarpy may accrue in other ways to apocarpous species, we reviewed previous studies of pollen-tube growth in apocarpous species and also documented pollen-tube growth in nine additional apocarpous species in six families. ? Anatomical studies of a scattering of apocarpous paleodicots, monocots, and eudicots show that, after transiting the style, 'extra' pollen tubes exit fully fertilized carpels and grow to other carpels with unfertilized ovules. In many species this occurs via openings in the simple carpels, as we report here for Sagittaria potamogetifolia, Sagittaria pygmaea, Sedum lineare, and Schisandra sphenanthera. ? The finding that extra-gynoecial pollen-tube growth is widespread in apocarpous species eliminates the possibility of a major fitness cost of apocarpy relative to syncarpy and may help to explain the persistence of, and multiple reversals to, apocarpy in the evolutionary history of angiosperms.     

Convergent elaboration of apocarpous gynoecia in higher advanced dicotyledons (Sapindales, Malvales, Gentianales)

The apocarpous gynoecia of three separate groups of higher advanced dicotyledons show postgenital fusion of their apical parts. In this fused region the pollen tube transmitting tissue of the carpels is united into a compitum, which provides advantages of a syncarpous to the apocarpous gynoecium. It is supposed that in at least some of these groups the general evolutionary trend of the angiosperms from apocarpy towards syncarpy is reversed.     

番荔枝科研究35.Guatteria类群和有关属的系统发育

Guatteria类群由4个新热带的属组成,即Guatteria,Guatteriopsis,Guatteriella和Heteropetalum。不同的作者基于不同的证据得出的它在番荔枝中的地位各不相同。基于宏观和微观的形态特征,对该类群进行了表型和分支分析。分支分析表明,所研究属的系统发育分支方式仅由极少数共同衍征支持,同型现象非常明显,所获得的唯一的最简约分支图可分为两个基本部分,即一个(假)合生心皮分支和一个离生心皮grade。在表征聚类图和主成分分析的三维构象图中同样可以区分出离生心皮和(假)合生心皮两个表征群,表征分析表明Guatteria类群处在其它离生心皮类和(假)合生心皮类的中间位置。然而分支分析表明Guatteria类群与番荔枝科中最进化的(假)合生心皮类有姊妹群关系。Guatteria类群是离生心皮类中最进化的一类。番荔枝科中离生心皮类和(假)合生心皮类在漫长的进化过程中经历了强烈的形态分化而显示出极大的形态差异,然而在系统发育上它们可以通过Guatteria类群作为纽带而联系起来。     

Multicarpellate gynoecia in angiosperms: occurrence,development, organization and architectural constraints

Most angiosperms have gynoecia with two to five carpels. However, more than five carpels (here termed ‘multicarpellate condition’) are present in some representatives of all larger subclades of angiosperms. In such multicarpellate gynoecia, the carpels are in either one or more than one whorl (or series). I focus especially on gynoecia in which the carpels are in a single whorl (or series). In such multicarpellate syncarpous gynoecia, the closure in the centre of the gynoecium is imprecise as a result of slightly irregular development of the carpel flanks. Irregular bumps appear to stuff the remaining holes. In multicarpellate gynoecia, the centre of the remaining floral apex is not involved in carpel morphogenesis, so that this unspent part of the floral apex remains morphologically undifferentiated. It usually becomes enclosed within the gynoecium, but, in some cases, remains exposed and may or may not form simple excrescences. The area within the remaining floral apex is histologically characterized by a parenchyma of simple longitudinal cell rows. In highly multicarpellate gynoecia with the carpels in a whorl, the whorl tends to be deformed into an H‐shaped or star‐shaped structure by differential growth of the floral sectors, so that carpels become aligned in parallel rows, in which they face each other with the ventral sides. In this way, a fractionated compitum may still be functional. Multicarpellate gynoecia (with the carpels in one whorl or series) occur in at least one species in 37 of the 63 angiosperm orders. In contrast, non‐multicarpellate gynoecia are present in at least one species of all 63 orders. The basal condition in angiosperms is more likely non‐multicarpellate. Multicarpellate gynoecia are restricted to flowers that are not highly synorganized. In groups with synorganized androecium and gynoecium and in groups with elaborate monosymmetric flowers, multicarpellate gynoecia are lacking. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174 , 1–43.     

The evolution of key functional floral traits in the early divergent angiosperm family Annonaceae

Potential key functional floral traits are assessed in the species‐rich early divergent angiosperm family Annonaceae. Pollinators (generally beetles) are attracted by various cues (particularly visual, olfactory, and thermogenic), with pollinators rewarded by nectar (generally as stigmatic exudate), heat, and protection within the partially enclosed floral chamber. Petals sometimes function as pollinator brood sites, although this could be deceptive. Annonaceae species are self‐compatible, with outcrossing promoted by a combination of protogyny, herkogamy, floral synchrony, and dicliny. Pollination efficiency is enhanced by pollen aggregation, changes in anthesis duration, and pollinator trapping involving a close alignment between petal movements and the circadian rhythms of pollinators. Most Annonaceae flowers are apocarpous, with syncarpy restricted to very few lineages; fertilization is therefore optimized by intercarpellary growth of pollen tubes, either by stigmatic exudate (suprastylar extragynoecial compitum) or possibly the floral receptacle (infrastylar extragynoecial compitum). Although Annonaceae lack a distinct style, the stigmas in several lineages are elongated to form “pseudostyles” that are hypothesized to function as sites for pollen competition. Flowers can be regarded as immature fruits in which the ovules are yet to be fertilized, with floral traits that may have little selective advantage during anthesis theoretically promoting fruit and seed dispersal. The plesiomorphic apocarpous trait may have been perpetuated in Annonaceae flowers as it promotes the independent dispersal of fruit monocarps (derived from separate carpels), thereby maximizing the spatial/temporal distance between seedlings. This might compensate for the lack of genetic diversity among seeds within fruits arising from the limited diversity of pollen donors.     

THE GYNOECIAL DEVELOPMENT AND SYSTEMATIC POSITION OF ALLAMANDA (APOCYNACEAE)

Allamanda exhibits an unusual type of gynoecial development in which the two carpels are free at initiation, but fuse completely during development, resulting in a unilocular ovary with parietal placentation at maturity. Whereas the majority of the Apocynaceae are characterized by an advanced type of gynoecium that is secondarily apocarpous, in Allamanda gynoecial evolution has proceeded one step further to secondary syncarpy. This condition is not known to occur in any other genus in the Apocynaceae and provides further evidence of the isolated position of Allamanda within the family.     

FUNCTIONAL SYNCARPY BY INTERCARPELLARY GROWTH OF POLLEN TUBES IN A PRIMITIVE APOCARPOUS ANGIOSPERM,ILLICIUM FLORIDANUM (ILLICIACEAE)

Fluorescence microscopy and histological studies have been used to show that in Illicium floridanum Ellis (Illiciaceae), a primitive apocarpous angiosperm, functional syncarpy is achieved by intercarpellary growth of pollen tubes. After pollen germinates on the separate stigmatic crests of the carpellary whorl, tubes grow within the carpels obliquely down and inward toward the central floral axis which is modified as a stigmalike “apical residuum.” In a restricted shallow region around the base of the apical residuum, some pollen tubes grow out between the unfused margins of the carpels and circumferentially around the surface of the apical residuum from where they may enter neighboring carpels. Some pollen germination and tube growth also occur on the apical residuum itself. The apical residuum with its associated unfused carpel margins acts as an extragynoecial compitum for pollen tube transfer between carpels, and, as such, is believed to represent a mechanism for increasing the efficiency of seed set. The pollen tube pathway of Illicium appears to be a primitive expression of a line of evolutionary development leading to syncarpous gynoecia through stages possibly exemplified by certain members of the Trochodendraceae (lower Hamamelididae).     

Within-carpel and among-carpel competition during seed development, and selection on carpel number, in the apocarpous perennial herb Helleborus foetidus L. (Ranunculaceae)

Apocarpous flowers share opportunities for post-fertilization ovule selection among more functional levels than syncarpous flowers, because the occurrence of a variable number of unfused carpels adds a new source of variation to the likelihood of successful female reproduction. The extent to which post-fertilization events might differ among these unfused carpels may promote variations in the reproductive strategies of plants. We report a study of the variation, within and among carpels and flowers, in seed production and mass in the apocarpous Helleborus foetidus (Ranunculaceae), in relation to the number of carpels per flower. Differences within and among carpels in female reproductive success were affected by carpel number and pollination environment. When analysing whole flowers as functional units we also found that the magnitude of the differences related to carpel number and pollination treatment actually depended on the “distribution” of pollen types within flowers. Thus, variable within-flower pollination environments, more likely to occur in apocarpous than in syncarpous flowers, may affect the strategies of resource allocation for fruit development at different stages of the reproductive process. Regarding seed production, we found that producing more flowers with four carpels was under directional; however, when mean diaspore mass was considered as a measure of fitness, directional selection was found on producing flowers with two and three carpels (the modal carpel number found in wild populations). We discuss ecological and developmental reasons which could explain the observed pattern, and conclude that selection on an optimum carpel number may be very variable across the species range, as the discussed reasons may impose constraints on eventual evolutionary response, thus contributing to the maintenance of the intra-individual variability in carpel number.     

Gynoecium structure and extra-gynoecial pollen-tube growth in an apocarpous species, <Emphasis Type="Italic">Sagittaria trifolia</Emphasis> (Alismataceae)

Apocarpy is regarded as an original feature obtained during the evolution of angiosperms. Compared with syncarpous plants, apocarpous plants have some adaptive disadvantages in apocarpous plants, for example, the number of offspring is lower under conditions of uneven pollen-tube distribution. However, in some apocarpous species, extra-gynoecial pollen-tube growth (EGPG) may remedy this disadvantage. We conducted micro-observations and field studies of Sagittaria trifolia, to investigate the gynoecium structure and the pathway of pollen-tube growth in the entire gynoecium. In a single-carpel pollination experiment, we found that the extra-gynoecial pollen tubes from a carpel of S. trifolia were able to fertilize approximately 13 carpels. Simulated EGPG in the entire gynoecium of S. trifolia revealed that its effect on the seed set could be divided into two stages: stage of low/high-level stigmas pollination, in which the cutoff point was about 0.1. The seed set would be markedly improved during the low-level stigmas pollination stage by EGPG when the maximum distance of extra-gynoecial pollen tubes could span three carpels, as in the present experiment. Our simulation also showed that the high pollen load could enhance the effect of EGPG on the seed set, and if the number of germinating pollen is triple the carpel number in the gynoecium, a 100% seed set rate would be obtained when approximately 50% of the stigmas are pollinated.     

Evolution of syncarpy in angiosperms: theoretical and phylogenetic analyses of the effects of carpel fusion on offspring quantity and quality

The repeated evolution of fused carpels (syncarpy) is one of the dominant features of angiosperm macroevolution. We present results of new phylogenetic and theoretical analyses to assess the frequency and nature of transitions to syncarpy, and the possible advantages of syncarpy over apocarpy under a variety of ecological conditions. Using a recent molecular estimate of angiosperm phylogeny, we ascertained that a minimum of 17 independent evolutionary transitions from apocarpy to syncarpy have occurred; about three‐quarters of these transitions allowed pollen tubes to cross between carpels and fertilize ovules that would otherwise be left unfertilized. Most of these transitions also intensified competition between pollen, potentially enhancing offspring fitness. The high proportion of evolutionary transitions promoting pollen competition and pollen‐tube access to all carpels supports the hypothesis that the main advantage of syncarpy is in increasing offspring quality and quantity. The potential advantages of syncarpy were more thoroughly evaluated by analytical and simulation studies. These showed that the advantage of syncarpy over apocarpy involving increased offspring‐quantity held under conditions of marginal pollination and declined with increasing pollination. The offspring‐quality advantage persisted over a wider range of conditions, including under quite high pollination rates.     

The unusual gynoecium structure and extragynoecial pollen-tube pathway in <Emphasis Type="Italic">Phytolacca</Emphasis> (Phytolaccaceae)

The fusion of carpels into a unified compound gynoecium is considered a dominant feature of angiosperm evolution and it also occurs by postgenital fusion during the gynoecium development in some apocarpous species. However, we found the reverse process, the separation of carpels from combined carpel primordia, during the development of the gynoecium in Phytolacca. Semithin sectioning and scanning electron microscopy were utilised to observe the structure and development of the gynoecia in Phytolacca acinosa and Phytolacca americana, fluorescence microscopy was utilised to observe the pollen tube growth in the gynoecia of the two species, and the topology method was applied to analyze the relationship between the gynoecium structure and pollen tube pathway. Although the gynoecia of P. acinosa and P. americana are both syncarpous, the degree of carpel fusion in the mature gynoecia of the two syncarpous species is different as a result of variant developmental processes. However, change in the degree of carpel fusion during the development of gynoecia in Phytolacca does not affect pollen tube growth because of the existence of the extragynoecial pollen-tube pathway. Thus, the change in the degree of carpel fusion in Phytolacca is primarily the result of diversification of developmental processes related to selection pressure.     

Unique growth paths of heterospecific pollen tubes result in late entry into ovules in the gynoecium of Sagittaria (Alismataceae)

• Pollen‐pistil interactions are a fundamental process in the reproductive biology of angiosperms and play a particularly important role in maintaining incipient species that exist in sympatry. However, the majority of previous studies have focused on species with syncarpous gynoecia (fused carpels) and not those with apocarpous gynoecia (unfused carpels).
• In the present study, we investigated the growth of conspecific pollen tubes compared to heterospecific pollen tubes in Sagittaria species, which have apocarpous gynoecia. We conducted controlled pollinations between S. pygmaea and S. trifolia and observed the growth of conspecific and heterospecific pollen tubes under a fluorescence microscope.
• Heterospecific and conspecific pollen tubes arrived at locules within the ovaries near simultaneously. However, conspecific pollen tubes entered into the ovules directly, whereas heterospecific tubes passed through the carpel base and adjacent receptacle tissue, to ultimately fertilize other unfertilized ovules. This longer route taken by heterospecific pollen tubes therefore caused a delay in the time required to enter into the ovules. Furthermore, heterospecific pollen tubes displayed similar growth patterns at early and peak pollination. The growth pattern of heterospecific pollen tubes at late pollination was similar to that of conspecific pollen tubes at peak pollination.
• Heterospecific and conspecific pollen tubes took different routes to fertilize ovules. A delayed entry of heterospecific pollen into ovules may be a novel mechanism of conspecific pollen advantage (CPA) for apocarpous species.

     

Primer development for the plastid region ycf1 in Annonaceae and other magnoliids

? Premise of the study: Primers were developed for a portion of the ycf1 plastid gene in magnoliid taxa to investigate the utility of ycf1 in phylogenetic analyses. ? Methods and Results: Twenty-six species across six families within the magnoliid group (Canellales, Piperales, Laurales, and Magnoliales) were sampled to examine the ability to amplify ycf1. Additionally, 29 accessions of Asimina and Deeringothamnus (Annonaceae) were sequenced to assess levels of variation in ycf1 compared to matK and trnL-F. ? Conclusions: Results indicate that ycf1 is easily amplified and sequenced. In Annonaceae, ycf1 provides more informative phylogenetic characters than commonly used markers such as matK and trnL-F.     

关于豆科植物心皮缝合线朝向的思考

当今植被和地球生态系统中多样性最高的类群是被子植物.豆科植物是被子植物中的第三大科, 因其重要的经济价值与人类的生活密切相关, 颇受植物学家的重视.百余年前植物学家已基本明确回答了豆科植物的许多形态学问题, 但仍然有一个问题不甚明确.单枚心皮是豆科植物的一个重要特征.植物学家认为该心皮缝合线朝向心皮的腹面.这种解读某种...     

Identifying clades in Asian Annonaceae: monophyletic genera in the polyphyletic Miliuseae

The tribe Miliuseae (Annonaceae) comprises six genera distributed in Asia: Alphonsea, Mezzettia, Miliusa, Orophea, Platymitra, and Phoenicanthus. A phylogenetic study to investigate the putative monophyly of the tribe and the intergeneric relationships is presented here. Nucleotide sequences of the plastid gene rbcL, trnL intron, and trnL-trnF intergenic spacer were analyzed from 114 Annonaceae taxa, including 24 Miliuseae species and two outgroups using maximum parsimony and Bayesian inference. The two data sets (rbcL and the trnL-trnF regions) were analyzed separately and in combination. Miliuseae were found to be polyphyletic due to the position of Mezzettia and are part of a large, predominantly Asian and Central-American clade (miliusoid clade). Although intergeneric relationships were poorly resolved, all genera, except Polyalthia, were monophyletic, supporting previous generic delimitation based on morphology. A group of three Polyalthia species seems the most likely sister group of Miliusa. Several infrageneric groups of Miliusa, Orophea, and Polyalthia are supported by both molecular and morphological data. No morphological synapomorphies have yet been found for the miliusoid clade. Molecular clades within the miliusoid clade, however, can be characterized by size and the shape of the outer petals, number of ovules per carpel, and the size of the fruits.     

Floral development in <Emphasis Type="Italic">Thermopsis turcica</Emphasis>, an unusual multicarpellate papilionoid legume

The vast majority of the species of family Leguminosae have an apocarpous monomerous gynoecium. However, only a few taxa regularly produce multicarpellate gynoecia. The only known species of papilionoid legumes which has both a typical “flag blossom” and more than one carpel is Thermopsis turcica (tribe Thermopsideae). We studied the floral ontogeny of T. turcica with special reference to its gynoecium initiation and development. Flowers arise in simple terminal racemes in a helical order and are subtended by bracts. Bracteoles are initiated but then suppressed. Sepals appear more or less simultaneously. Then, petals emerge and remain retarded in development until later stages. The gynoecium usually includes three carpels with an abaxial one initiating first and two adaxial carpels arising later and developing somewhat asynchronously. The abaxial carpel appears concomitant with the outer stamens and is always oriented with its cleft toward the adaxial side, while the adaxial carpels face each other with their clefts and have them slightly turned to the adaxial side. Rarely uni-, bi- or tetracarpellate flowers arise. Seed productivity of T. turcica is on approximately the same level as in unicarpellate species of Thermopsis hence supporting the fact that the multicarpellate habit is adaptive or at least not harmful in this species.     

Rethinking the evolution of extant sub‐Saharan African suids (Suidae,Artiodactyla)

Gongora, J., Cuddahee, R. E., do Nascimento, F. F., Palgrave, C. J., Lowden, S., Ho, S. Y. W., Simond, D., Damayanti, C. S., White, D. J., Tay, W. T., Randi, E., Klingel, H., Rodrigues‐Zarate, C. J., Allen, K., Moran, C. & Larson, G. (2011). Rethinking the evolution of extant sub‐Saharan African suids (Suidae, Artiodactyla). —Zoologica Scripta, 40, 327–335. Although African suids have been of scientific interest for over two centuries, their origin, evolution, phylogeography and phylogenetic relationships remain contentious. There has been a long‐running debate concerning the evolution of pigs and hogs (Suidae), particularly regarding the phylogenetic relationships among extant Eurasian and African species of the subfamily Suinae. To investigate these issues, we analysed the mitochondrial and nuclear DNA sequences of extant genera of Suidae from Eurasia and Africa. Molecular phylogenetic analyses revealed that all extant sub‐Saharan African genera form a monophyletic clade separate from Eurasian suid genera, contradicting previous attempts to resolve the Suidae phylogeny. Two major sub‐Saharan African clades were identified, with Hylochoerus and Phacochoerus grouping together as a sister clade to Potamochoerus. In addition, we find that the ancestors of extant African suids may have evolved separately from the ancestors of modern day Sus and Porcula in Eurasia before they colonised Africa. Our results provide a revision of the intergeneric relationships within the family Suidae.     

THE PALM GYNOECIUM

The morphology, anatomy, and histology of the gynoecia at or close to anthesis are described for 20 genera of palms selected to represent different taxonomic alliances and to include major gynoecial types within the family. Palms may have 1–10 carpels, but most have three. Fifteen genera, including 14 coryphoid palms and the monotypic Nypa fruticans, are apocarpous and the remainder, approximately 190, are syncarpous. Fusion of carpels in some gynoecia begins in the base, in others in the styles. Pseudomonomerous pistils occur in several different alliances: the ovarian parts of two carpels are reduced but three usually equal and functional styles and stigmas are present. The carpel is often follicular in shape with the ventral suture open or, more frequently, partially or completely closed. The carpel may be stipitate or sessile and usually has a conduplicate laminar part. Most carpels are spirally and laterally inserted on the receptacle, but the carpel in some unicarpellate genera (e.g., Thrinax) appears terminal. Stipes, ovarian parts, styles, and stigmas vary in structure and development. Septal nectaries which differ in size, in the presence or absence of specialized canals, and in position, characterize all genera of some groups but only some genera of others. Diverse vascular configurations in the bases of gynoecia vary according to the extent of the floral axis, the development of carpellary stipes, and the connation of the carpels and their adnation to the tip of the floral axis. Four types of carpellary vascular systems are present in the genera described: (1) most palm carpels have three major traces consisting of a dorsal bundle and two ventral bundles, and they may also have up to four pairs of lateral bundles or occasionally more; (2) in certain cocosoid palms no ventral bundles can be distinguished, but a dorsal bundle, many parallel lateral bundles, and a row of immature ventral strands vascularize each carpel; (3) carpels of Phytelephas have a dorsal bundle, two pairs of major lateral bundles and about four pairs of shorter lateral bundles, with no identifiable ventral bundles; (4) carpels of Nypa have many dichotomously branched bundles but none that are recognizable as dorsal, ventral, or lateral strands. Additional peripheral bundles or systems may be present in each of the above types. Ovules are supplied by 1–15 bundles. These are derived either from the carpellary stele; from ventral bundles only; from ventral, lateral, and dorsal bundles; or from a combination of these origins. Certain areas of the gynoecia or certain parts of dorsal carpellary walls in some genera are much less mature at anthesis than surrounding tissues. Implications for floral biology and relationships within the palms and of palms to other groups are discussed.     

A previously unrecognized radiation of ranid frogs in Southern Africa revealed by nuclear and mitochondrial DNA sequences

In sub-Saharan Africa, amphibians are represented by a large number of endemic frog genera and species of incompletely clarified phylogenetic relationships. This applies especially to African frogs of the family Ranidae. We provide a molecular phylogenetic hypothesis for ranids, including 11 of the 12 African endemic genera. Analysis of nuclear (rag-1, rag-2, and rhodopsin genes) and mitochondrial markers (12S and 16S ribosomal RNA genes) provide evidence for an endemic clade of African genera of high morphological and ecological diversity thus far assigned to up to five different subfamilies: Afrana, Cacosternum, Natalobatrachus, Pyxicephalus, Strongylopus, and Tomopterna. This clade has its highest species diversity in southern Africa, suggesting a possible biogeographic connection with the Cape Floral Region. Bayesian estimates of divergence times place the initial diversification of the southern African ranid clade at approximately 62-85 million years ago, concurrent with the onset of the radiation of Afrotherian mammals. These and other African ranids (Conraua, Petropedetes, Phrynobatrachus, and Ptychadena) are placed basally within the Ranoidae with respect to the Eurasian groups, which suggests an African origin for this whole epifamily.     

STUDIES ON THE FLORAL ANATOMY OF THE CUNONIACEAE

Twenty-two genera representing sixty-two species of Cunoniaceae and Davidsonia were examined with respect to floral anatomy. Sepals are vascularized by three traces with the lateral traces of adjacent sepals united. Pancheria is unique for the family with species in which the sepals are vascularized by a single, undivided bundle. Petals, when present, and stamens, are uniformly one-trace structures. A general tendency exists within the family for the principal floral bundles to unite in various ways, with fusions evident between calyx, corolla, and androecial vascular supplies. Carpel number ranges from two to five and the gynoecium is generally surrounded by a prominent disc. Gynoecia of Ceratopetalum and Pullea are “half-inferior.” The number of ovules per carpel locule ranges from one to numerous. Ventral carpel sutures range from open to completely sealed at the level of placentation. Carpels of the apocarpous genus Spiraeanthemum (incl. Acsmithia) are vascularized by a dorsal bundle and either three or four bundles constituting the ovular and wing vasculation in the ventral position, a condition unlike other members of the family. Ovules are supplied by the median ventral bundle. More advanced bicarpellate gynoecia within the family are predominately vascularized by a dorsal and two ventral bundles although a variable number of additional lateral wall traces may be present. A major trend exists toward fusion of the ventral bundles of adjacent carpels in the ovary of both bicarpellate and multicarpellate plants. At the base of the styles the fused ventral strands separate and extend along with the dorsal carpellary bundles into styles of adjacent carpels. In Pullea the ventral bundles terminate within the ovules. The united ventral carpellary bundles in Aphanopetalum, Gillbeea, and Aistopetalum lie in the plane of the septa separating adjacent carpels. Ovules are vascularized by traces originating from the vascular cylinder at the base of the gynoecium or by traces branching from the ventral bundles. Ovular traces in each carpel are united, or remain as discrete bundles, prior to entering the placenta. Tannin and druses are common throughout all floral parts. Although floral anatomy generally supports the position of Cunoniaceae near Saxifragaceae and Davidsoniaceae, the evolutionary relationship of the Cunoniaceae to the Dilleniaceae is uncertain.