COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE VII. POMOIDEAE: CHAENOMELES,CYDONIA, DOCYNIA

The multi-ovulate pomoids, Chaenomeles, Cydonia, and Docynia, all have closed sutures and extensive fusion between carpel and floral cup and between ovular and wing bundles. Although the ovules in Docynia are generally apotropic and few in number (4–7), the ovules in the other two genera are pleurotropic and numerous (15–48). A statistical treatment of the whole tribe of Pomoideae shows that in carpels with open sutures ovular and wing bundles definitely tend to be separate while in those with closed sutures these bundles tend to be fused. To a lesser degree carpels with open sutures also tend to have bitegmic ovules, separate carpels, and a lesser extent of fusion between carpel and floral cup, while carpels with closed sutures tend to have monotegmic ovules, united carpels, and a greater extent of fusion between carpel and floral cup.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE. III. POMOIDEAE: CRATAEGUS,HESPEROMELES, MESPILUS,OSTEOMELES

The carpels in Crataegus, Hesperomeles, Mespilus, and Osteomeles appear to constitute a morphologically related group: all have bony pits, ovules that tend to be acollateral (usually superposed), and clearly separate ovular and wing bundles, i.e., no “ventral” bundles, at the level of ovular insertion. In species whose carpels have no sutural opening, the integuments are more extensively fused with one another, the degree of intercarpellary fusion tends to be greater, and the carpels are fused with the floral cup to relatively higher levels than in those species whose carpels have a sutural opening. In the few cases in which wing and ovular bundles are adnate at the locular base (Crataegus monogyna, Mespilus, Osteomeles anthyllidifolia, O. Schwerinae), the extent of inter- and extracarpellary fusion and sutural closure is among the most advanced.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE. IV. POMOIDEAE: CHAMAEMELES,COTONEASTER, DICHOTOMANTHES,PYRACANTHA

The carpels of Chamaemeles, Cotoneaster, Dichotomanthes, and Pyracantha tend to be separate from one another, their sutures tend to be closed, and they become more or less bony at maturity. However, aside from having collaterally placed ovules, they do not appear to be structurally similar. There seem to be 2 different evolutionary trends in the ovular bundle–wing bundle relationship: in Pyracantha, progressive fusion between the ovular bundle and the wing bundle has led to the formation of a “ventral” bundle; in Cotoneaster, and possibly Chamaemeles, the wing bundle has become reduced and rather attenuated. A primitive pomoid state may be represented by the carpel of Dichotomanthes, which is completely free of the floral cup and in which wing and ovular bundles are separate. Differences in sutural closure appear only in Cotoneaster, and in species of that genus the wing bundles and ovular bundles tend to be fused if the suture is closed, and separate if it is open.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE. II. PRUNOIDEAE: MADDENIA,PYGEUM; OSMARONIA

A survey of species of the prunoid genera, Maddenia and Pygeum, and of the genus Osmaronia has been made. The ovules of all are pendent, campylotropous, and epitropic. In the prunoids, the ovular supply is intimately connected with a central vascular plexus in the base of the carpel; that plexus is absent from Osmaronia. The prunoid carpels are marked by an extensive degree of fusion among the ovular and wing bundles, by fusion of the sutural margins, by fusion of the 2 integuments of the ovule to a single massive one, and by the presence of 3 or 5 well-developed bundles in the base. The carpel of Osmaronia also has a strongly fused bipartite ovular supply, separate bundles of which, however, become very much attenuated before reaching the funiculus; it has independent ovular and wing bundles, completely separate carpellary margins, 2 clearly separate integuments in the ovule, and 6 distinctive bundles in the carpel base. At the funiculus, the wing bundle of Osmaronia is connected with the adjoining weak ovular bundle by a well-developed vascular branch. Various particularities in the morphology of Osmaronia lend support to its segregation into a unique tribe, the Osmaronieae of Rydberg.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE. V. POMOIDEAE: AMELANCHIER,ARONIA, MALACOMELES,MALUS, PERAPHYLLUM,PYRUS, SORBUS

The carpels of 2 groups of pomoid genera, Amelanchier, Malacomeles, Peraphyllum and Aronia, Malus, Pyrus, and Sorbus, were analyzed morphologically. Open sutures are associated with a lesser extent of tegumentary fusion and ovular bundle–wing bundle fusion than are closed sutures. However, in the genera as a whole (and particularly in Aronia and Sorbus), the extent of sutural closure is inversely related with the amount of intercarpellary adhesion and with the fusion of carpels to the floral cup. In the Amelanchier group and in Malus and Pyrus, ovular- and wing-bundle fusion is directly related with intercarpellary adhesion. Malus and Pyrus have closer structural resemblances with one another than they have with Aronia and Sorbus.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE. I. PRUNOIDEAE: PRUNUS

A study of the carpel in 27 species of Prunus has shown certain notable structural relationships associated with the extent of closure of the carpellary margins. These relationships involve the degree of fusion of the 2 integuments, the number of vegetative bundles in the base of the carpel, the extent of fusion of the ovular bundles with one another and with the wing bundles, the relative size of the ovular bundles, and the relative development of the central vascular plexus. The comparative evidence strongly supports a primitively separate state of ovular and vegetative bundles. The significance of this finding is discussed.     

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.     

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.     

THE AFFINITIES OF PRINSEPIA (ROSACEAE)

Sterling, C. (U. California, Davis.) The affinities of Prinsepia (Rosaceae). Amer. Jour. Bot. 50(7): 693–699. Illus. 1963.—Anatomical study of the carpels of 4 species of Prinsepia has shown that at flowering the 2 ovules are erect and pleurotropic. The funiculus is on the dorsal and lower side of the ovule; the micropyle faces a large obturator on the ventral side. The carpellary margins are separated by a fissure below the funicular insertion, but above this level they are fused. The style is laterally inserted on the ventral face of the carpel; it is vascularized only by the wing bundles and the recurving dorsal bundle. At the base of the ovary, 2 ovular bundles depart from the vascular cylinder and run separately, each to its respective ovule. In carpel morphology, ovular position, ovule structure, and vascular anatomy, Prinsepia is not a prunoid type. Although its features on the whole resemble those of chrysobalanoid plants, there are notable differences. Consequently, Prinsepia is assigned to a new subfamilial group in the Rosaceae, the Prinsepioideae. Some phylogenetic considerations are discussed briefly.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE IX. SPIRAEOIDEAE: QUILLAJEAE,SORBARIEAE

A comparative study of carpellary structure in the spiraeoid subtribes Qui lajeae and Sorbarieae has shown that morphological inter-relationships are similar to those of other Rosaceae. When the suture is closed the carpels tend to be coherent and the ovular and wing bundles tend to be fused. These relationships are statistically significant in the Spiraeo deae as a whole. The construction of the gynoecium in Lindleya and in most species of Vauquelinia resembles that of a pomoid. Other features of a pomoid-spiraeoid affinity have been discussed.     

Floral development of Cardiopteris,with emphasis on gynoecial structure and ovular morphology

Cardiopteris is unique in the expanded Cardiopteridaceae for several distinctive features, including its gynoecial structure and ovular morphology. We studied the floral development of Cardiopteris to clarify floral morphology and document floral development. Cardiopteris has three carpel primordia, which are separate at their tips but congenitally fused at their bases. The synascidiate zone (the fused proximal part) develops into the unilocular ovary; the three discrete carpel apices diverge in development: the apex of the adaxial carpel differentiates into a style and stigma, while the apices of the two lateral-abaxial carpels elongate and develop into a fleshy appendage only after fertilization. The ovules are attached to the lateral-abaxial carpels. At anthesis, the ovules are ategmic and orthotropous without funicles (morphologically undifferentiated). Functional differentiation occurs in the three carpels of Cardiopteris: the adaxial one is the site of pollination, while the lateral-abaxial two produce ovules. The ategmic orthotropous ovule is unusual in Cardiopteridaceae and is an apomorphy of Cardiopteris.     

Comparative morphology of the carpel in the Liliaceae: Baeometra, Burchardia and Walleria

The pistils in Baeometra, Burchardia and Walleria ate tricarpellate, and their ovules are mostly bitegmic. Baeometra has free styles and deep septal invaginations between the carpels. Its pistil is innervated by three dorsal bundles, three compound septal bundles (each of which may divide into two simple septal bundles above), six placental bundles, and six adjoining auxiliary placental bundles. The pistil of Burchardia resembles that of Baeometra , except that there are six simple septal bundles throughout and no auxiliary placental bundles. In Walleria the wings of adjoining carpels are completely fused (except for rare septal glands); there is a single compound style; additional vascular tissue is present in the central axis of the pistil up to the lowermost ovules; the carpels are fused with the floral cup above the base of the locules; and raphide idioblasts are present. Walleria has six "ventral" bundles, each of which appears to be the fusion product of a placental bundle with a simple septal bundle. Tribal affinities of these genera are discussed.     

FLORAL ONTOGENY OF ILLICIUM FLORIDANUM,WITH EMPHASIS ON STAMEN AND CARPEL DEVELOPMENT

The ontogeny of the flower and fruit of Illicium floridanum Ellis, the Star Anise, was investigated. Each of 5 or 6 bracts in each mixed terminal bud subtends either a vegetative or floral bud. The solitary flowers occur in terminal or axillary positions. Each flower has 3–6 subtending bracteoles arranged in a clockwise helix. The flowers in our material have 24–28 tepals, 30–39 stamens, and usually 13 (rarely 19) uniovulate carpels. Tepals and stamens are initiated in a low-pitched helix; carpels later appear whorled, but arise successively at different levels on the apical flanks. The floral apex is high-convex in outline with a tunica-corpus configuration; it increases in height and width throughout initiation of the floral appendages. Tepals, stamens, and carpels are initiated by one to several periclinal divisions in the subsurface layers low on the apical flanks, augmented by cell divisions in the outer layers of the corpus. The carpel develops as a conduplicate structure with appressed, connivent margins. Procambium development of floral appendages is acropetal and continuous. Bracteoles, tepals, stamens and carpels are each supplied by 1 trace; the carpellary trace splits into a dorsal and an ascending ventral sympodium. The latter bifurcates to form 2 ventral bundles. The ovular bundle diverges from the ventral sympodium. Ovule initiation occurs in a median axillary position to the carpel, an unusual type of ovule initiation. The fruit vasculature is greatly amplified as the receptacle and follicles enlarge. After carpel initiation an apical residuum persists which is not vascularized; a plate meristem develops over its surface to produce a papillate structure.     

Comparative floral structure and systematics in Celastrales (Celastraceae, Parnassiaceae, Lepidobotryaceae)

Floral morphology, anatomy and histology in the newly circumscribed order Celastrales, comprising Celastraceae, Parnassiaceae and Lepidobotryaceae are studied comparatively. Several genera of Celastraceae and Lepidobotrys (Lepidobotryaceae) were studied for the first time in this respect. Celastraceae are well supported as a group by floral structure (including genera that were in separate families in earlier classifications); they have dorsally bulged‐up locules (and thus apical septa) and contain oxalate druses in their floral tissues. The group of Celastraceae and Parnassiaceae is also well supported. They share completely syncarpous gynoecia with commissural stigmatic lobes (and strong concomitant development of the commissural vascular bundles but weak median carpel bundles), only weakly crassinucellar or incompletely tenuinucellar ovules with an endothelium, partly fringed sepals and petals, protandry in bisexual flowers combined with herkogamy by the movement of stamens and anther abscission, and stamens fused with the ovary. In contrast, Lepidobotryaceae are more distant from the other two families, sharing only a handful of features with Celastraceae (not Parnassiaceae), such as pseudohermaphroditic flowers, united stamen bases forming a collar around the gynoecium and seeds with a conspicuous aril. However, all three families together are also somewhat supported as a group and share petals that are not retarded in late floral bud development, 3‐carpellate gynoecia, ventral slits of carpels closed by long interlocking epidermal cells and pollen tube transmitting tissue encompassing several cell layers, both integuments usually more than two cell layers thick, and only weak or lacking floral indumentum. In some molecular analyses Celastrales form an unsupported clade with Malpighiales and Oxalidales. This association is supported by floral structure, especially between Celastrales and Malpighiales. Among Celastrales, Lepidobotryaceae especially share special features with Malpighiales, including a diplostemonous androecium with ten fertile stamens, epitropous ovules with an obturator and strong vascularization around the chalaza. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149 , 129–194.     

Taxonomic studies ofAsarum sensu lato

The floral vascular anatomy of 12 species representing each ofAsarum s. str.,Asiasarum, Geotaenium, Heterotropa andHexastylis are compared to clarify intergeneric relationships. The five genera have basically similar structures in floral morphology and vasculature, and consistently have a six-carpelled compound ovary and the associated similar placental vasculature. They show, however, a significant difference in the position and the constituent of the “ventral” carpellary bundles in the placental axis betweenAsiasarum-Heterotropa-Hexastylis andAsarum-Geotaenium. InAsiasarum, Heterotropa andHexastylis the ventral bundles of each carpel are basically free and antilocular as expected in the least specialized compound ovary of angiosperms; in contrast, inAsarum andGeotaenium the ventral carpellary bundles are antiseptal and heterogenous (i.e., formed by the lateral fusion of ventral bundles of adjacent carpels). Shared probable apomorphic floral vasculature, as well as shared single style-column, suggests the closest mutual relationships betweenAsarum andGeotaenium. In terms of floral morphology and anatomy,Asiasarum, Heterotropa andHexastylis retain plesiomorphies. Possible chromosomal evolution in the related genera is also discussed.     

Comparative floral structure and systematics in Crossosomatales (Crossosomataceae, Stachyuraceae, Staphyleaceae, Aphloiaceae, Geissolomataceae, Ixerbaceae, Strasburgeriaceae)

Floral structure of all putative families of Crossosomatales as suggested by molecular studies was comparatively studied. The seven comprise Crossosomataceae, Stachyuraceae, Staphyleaceae, Aphloiaceae, Geissolomataceae, Ixerbaceae, and Strasburgeriaceae. The entire clade (1) is highly supported by floral structure, also the clades (in sequence of diminishing structural support): Ixerbaceae/Strasburgeriaceae (2), Geissolomataceae/Ixerbaceae/Strasburgeriaceae (3), Aphloiaceae/Geissolomataceae/Ixerbaceae/Strasburgeriaceae (4), and Crossosomataceae/Stachyuraceae/Staphyleaceae (5). Among the prominent floral features of Crossosomatales (1) are solitary flowers, presence of a floral cup, imbricate sepals with outermost smaller than inner, pollen grains with horizontally extended endoapertures, shortly stalked gynoecium, postgenitally united carpel tips forming a compitum, stigmatic papillae two‐ or more‐cellular, ovary locules tapering upwards, long integuments forming zigzag micropyles, cell clusters with bundles of long yellow crystals, mucilage cells, seeds with smooth, sclerified testa and without a differentiated tegmen. Clade (2) is characterized by large flowers, petals forming a tight, pointed cone in bud, stamens with long, stout filaments and sagittate anthers, streamlined, conical gynoecium, antitropous ovules, rudimentary aril, lignified, unicellular, T‐shaped hairs and idioblasts with striate mucilaginous cell walls. Clade (3) is characterized by alternisepalous carpels, punctiform stigma formed by postgenitally united and twisted carpel tips, synascidiate ovary, only one or two pendant ovules per carpel, nectary recesses between androecium and gynoecium. Clade (4) is characterized by pronounced ‘pollen buds’. Clade (5) is characterized by polygamous or functionally unisexual flowers, x‐shaped anthers, free and follicular carpels (not in Stachyuraceae). Crossosomataceae and Aphloiaceae, although not retrieved as a clade in molecular studies, share several special floral features: polystemonous androecium; basifixed anthers without a connective protrusion; stigma with two more or less decurrent crests; camplyotropous ovules and reniform seeds; simple, disc‐shaped nectaries and absence of hairs. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 147 , 1–46.     

HISTOGENESIS OF THE ANDROECIUM AND GYNOECIUM IN DOWNINGIA BACIGALUPII

A histogenetic investigation of the synandrous androecium and syncarpous gynoecium in the flower of Downingia bacigalupii Weiler (Campanulaceae; Lobelioideae) was undertaken for the purpose of comparing the modes of initiation, early growth and fusion in these floral whorls with that reported previously for the perianth in this species. Stamens are initiated as separate organs from the second tunica layer and underlying corpus regions of the concave floral meristem. Subsequent growth of stamens involves apical and intercalary growth in length and rudimentary marginal growth in breadth. Tissues of the four microsporangia originate from hypodermal sporangial initial cells and the filament is formed by intercalary growth at the base of the anther. Lateral fusion of stamens is ontogenetic and involves cuticular fusion of adjacent epidermal layers. The two emergent carpel primordia arise as crescentic organs by periclinal divisions in the second tunica layer and corpus zones. Carpel primordia also undergo apical and intercalary growth in length as well as extensive marginal growth in breadth. Radial growth in carpels is mediated by an adaxial meristem which shows its greatest concentration of activity at the carpel margins. Carpel fusion appears to be partially ontogenetic accompanied by zonal growth. Closure of the stylar canal is by the formation of a transmitting tissue derived from the protodermal layers of the adaxial carpel surfaces. A discoid nectary is initiated around the base of the style and formation of the inferior ovary is by intercalary growth of the base of the concave floral bud. The two parietal placentae originate as longitudinal outgrowths from the walls of the floral cup. Ovule initiation is simultaneous at first and then intercalary during subsequent elongation of the ovary. The ovules are anatropous, unitegmic and tenuinucellate. Stamen and carpel procambium shows a slight delay in differentiation when compared to that reported for the perianth and bract, but in all other respects carpels resemble other floral organs in their patterns of histogenesis and early growth. Stamens diverge from the other floral organs in their early pattern of growth, but a consideration of all features of their histogenesis suggests an appendicular rather than an axial interpretation of these organs.     

Ontogeny,function and evolution of extreme floral construction inMonimiaceae

In at least 4 genera of theMonimiaceae (Tambourissa, Wilkiea, Kibara, Hennecartia) extremely specialized flowers with a hyperstigma occur, i.e. a secretory zone in the narrow entrance of the floral cup. The mucilaginous secretion of the hyperstigma and of the carpels produces a transmitting medium for pollen tubes continuous from the mouth of the floral cup to the ovules. As to their floral morphology, the two extreme types,Hortonia andTambourissa, are connected gradually by various other genera. Possible evolutionary trends and systematic problems are outlined.     

Comparative morphology of the carpel in the Liliaceae: Wurmbaeae

The two genera of Buxbaum's tribe Wurmbaeae, Anguillaria and Wurmbea , have multiovulate carpels. There are deep septal indentations between the carpels of Anguillaria , but the wings of adjoining carpels are fused to solid septa in most species of Wurmbea. In Anguillaria the carpels have open sutures or prominent commissural markings; in Wurmbea the carpels generally lack these characteristics, and some species have a vascularized, columella-like axis in the centre of the pistil. In both genera there are a dorsal bundle, lateral bundles, and two placental bundles in each carpel. At the inner edge of the septum there are one or two septal bundles in Anguillaria and one or none in Wurmbea. The ovules are monotegmic, the integument and funiculus being partly fused in Anguillaria and mostly fused in Wurmbea. An obturator is present in Anguillaria but absent from most species of Wurmbea.     

Floral morphology of Maloideae (Rosaceae) and its systematic relevance

Flowers of 169 species of Rosaceae subfamily Maloideae, which were chosen to represent the taxonomic and geographic diversity of the group, were studied to ascertain their morphological variation and its systematic relevance. We describe and illustrate variation in size, indumentum, color, and macroscopic structural features. Most maloid species have syncarpous flowers with two to five carpels in which the ovary is at least three-quarters inferior, whereas species of other Rosaceae subfamilies have apocarpous or unicarpellate flowers with superior ovaries. However, maloid flowers show significant variation in the degree of carpel connation and of ovary adnation to the hypanthium. Cotoneaster, Heteromeles, and Pyracantha are completely apocarpous, and Dichotomanthes is perigynous with a completely superior ovary. Thus, no one floral character is sufficient to separate the Maloideae from other subfamilies of Rosaceae. Differences among their flowers support our recognition of Malus, Pyrus, and Sorbus as separate genera. Further, we argue for removal of Docyniopsis and Eriolobus from Malus, division of Sorbus into several genera, and union of Aronia, Photinia, and Stranvaesia. No floral characters support the traditional dichotomy of the subfamily into tribes Crataegeae and Sorbeae.