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 Liliaceae: Glorioseae

The pistils of the Glorioseae (Gloriosa, Littonia, Sandersonia) are generally tricarpellate and alike. Virtually all have closed sutures at flowering; they have many ovules, some of which are barely bitegmic, with inner integuments often nearly fused with nucellar remnants; and there is usually but one compound septal bundle in the inner edge of a septum. In two species of Littonia , the compound septal bundle divided to form two simple septal bundles; but in many other plants it remained undivided, and in some it died out, still undivided, below the locular apex. Most of the placental and septal bundles are vascularized in large part by three alternate (compound septal) bundles at the base of the locules and sometimes by branches from the lateral bundles. Three large (compound) placental bundles are formed just below the lowermost ovular insertion, and each then divides in two to furnish ovular branches along their ascent. Occasional auxiliary placental bundles lie between the septal bundle and the placental bundles in the septum (Gloriosa, Sandersonia).     

Comparative morphology of the carpel in the Liliaceae: Iphigenieae

The pistil in the flowers of the Iphigenieae (Camptorrhiza, Iphigenia, Omithoglossum) is usually tricarpellate. The carpels are coherent generally, with closed sutures and seemingly bitegmic ovules. Camptorrhiza differs from the others in having a single compound style. The pistils of most species of these genera have a common vascular structure: three dorsal bundles which run into the style(s), a number of lateral bundles, six placental bundles, and up to three compound septal bundles. The latter nine bundles usually differentiate from a central vascular plexus above the base of the locules. There may be fewer than three septal bundles in some specieS. When present, the septal bundles usually die out in the ovuliferous region, but in some cases they persist to the apex of the locules.     

Comparative morphology of the carpel in the Liliaceae: Colchiceae (Colchicum)

The pistil of Colchicum is syncarpous, the carpels having open sutures or well-marked commissures and many bitegmic ovules of variable orientation. Although the vascularization of the carpel is also variable, there are usually three dorsal bundles and three alternate, septal bundles at the base of the pistil, with occasionally some placental bundles at that level. More often the placental bundles, differentiating basipetally, appear to establish connections with the septal bundles higher up, at the lowermost ovular insertion level. The septal bundles divide in two more frequently in pistils in which the carpellary suture is open than in those in which it is closed.     

Comparative morphology of the carpel in the Liliaceae: Veratreae

The genera of the Veratreae, a tribe of the Melanthioideae, have many features in common: there are usually many ovules, except for Amianthium (with 2 4), arranged in 2 -4 longitudinal placental rows per carpel; all are bitegmic, basipetal, and campylotropous. Of 37 species examined, only 2 have open sutures at the lowermost level of ovular insertion, but 13 species have holes in the centre of the pistil. These holes may represent possible stages in the evolutionary closure of previously open sutures. Most flowers were epigynous, only 11 being hypogynous-perigynous. The tribe as a whole is marked by the presence of 3 composite (heterologous) vascular bundles, composed of joined staminal and tepallary bundles alone and 3 composite bundles, as above, fused to a dorsal bundle. The bundles were united below the locular base in all genera except Schoenocaulon and Toxicoscordion. Two major kinds of central cylinder arrangement occurred at the level of the lowermost ovular insertion: either 6 inverted ventral bundles or 6 simple septal bundles, with normally arranged (or sometimes inverted) xylem and phloem centrifugally located and 6 simple placental bundles, with inverted xylem and phloem, at the centripetal end of the septum. Generally each septal bundle united with its nearest adjoining placental bundle about the mid-locular level.     

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.     

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.     

Comparative morphology of the carpel in the Liliaceae: Neodregeae

The structure of the carpel has been studied in flowers of the Neodregeae ( Dipidax and Neodregea ). Except in D. triquetra , which is syncarpous, the carpels are united below and free above. A dorsal bundle, two or more lateral bundles, and two placental bundles supply each multiovulate carpel. The six placental bundles of the tricarpellate pistil are united by twos in the lower part of the pistil, forming three opposite compound placental bundles in most species of Dipidax and three alternate bundles in D. triquetra and Neodregea : In the latter, an additional septal bundle continues upward as a branch from the compound placental bundle. Sutural openings are usually short and restricted to the top of the locule. All the Neodregeae have monotegmic ovules.     

Comparative morphology of the carpel in the Liliaceae: Helonieae

Most Helonieae have only slight septal indentations between the three carpels: in Xerophyllum deep septal clefts extend centripetally and completely enclosed, narrow septal pockets occur in Metanarthecium . Other unique generic features are found: tepallary-staminal nectarial glands in Heloniopsis , zygomorphy in Chionographis , and dioecism in Chamaelirium . The carpels are biovulate in Chionographis; there are two to several ovules per carpel in Xerophyllum; 8–12 ovules occur in the carpel of Chamaelirium; and numerous bitegmic ovules are borne in many longitudinal rows on enlarged placentae in Helonias, Heloniopsis, Metanarthecium , and Ypsilandra . Except for Metanarthecium , this last-named group of genera displays a near ring composed of 'accessory' placental bundles and a compound septal bundle (with normally oriented xylem and phloem) in cross-section at the inner edge of each septum. Ventral bundles occur in the other four genera.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Floral vascular anatomy ofConvallaria majalis L. andC. keiskei miq. (liliaceae-convallariinae)

In comparing the floral vascular anatomy ofConvallaria majalis andC. keiskei a similar pattern of vasculature was shown. Both have pedicels with six (3 large +3 small) bundles which via radial division and fusion form the tepal, stamen and ovary traces. The outer tepal and outer stamen traces, the dorsals and placentals (i.e. ventral supply) arise from the larger three pedicel bundles, while the inner tepal and inner stamen traces and the septal axials arise from the smaller three. The dorsals, septal axials, and all of the stamen and tepal bundles are fusion products, while the placentals are free, though arising from compound bundles. The overy vasculature lacks both lateral peripherals and terminal cross-connections between the inner bundles and the outer dorsals. The placentation is only axile basally, since the three septa are freed at the mid-ovary level, and the resulting common, upper carpellary cavity is continuous with the hollow style. Normally four ovules are observed in each carpel, with the lower tier associated with the lower solid central axis, and the upper tier associated with the freed septa. The orientation of the ovules is varied (heterotropic). An internal system of stigmatoidal tissue is continuous from the base of each locule to the stigma, and involves micropylar associated obturators. Raphides characterize mature ovaries of both species, though both lack septal glands and septal grooves.     

Biosystematic studies onMaianthemum (Liliaceae-Polygonatae)

A similar floral vascular anatomy involving a constant dimerous, bicarpellate plan for each of the threeMaianthemum species is reported. All of the tepal, stamen and ovary traces are derived via repeated radial division of two pedicel bundles. The four tepal and stamen traces are fusion products, as are the two dorsals. A third, smaller (vestigial) pedicel bundle which continues unbranched and uninvolved into the ovary was observed in all three species. It could indicate a past reduction from a trimerous, tricarpellate condition, and gives a basis for comparison to the closely related genusSmilacina. The gynoecial vasculature lacks peripheral laterals, septal axials and terminal cross-connections between the dorsal and ventral supplies. The placentation is only apparently axile, since the two septa divide at the mid-ovary level. Consistently the four co-lateral ovules which are anatropous and bitegmic are supplied by four free placentals. The placentals supplying the two ovules of a given carpel have had a common origin in a single pedicel bundle. Raphides characterize post-fertilization ovaries in all species. ADrusa-type of embyro sac formation shown forM. dilatatum corresponds with that known for the other species. An internal stigmoidal tissue system involving micropylar obturators extends from the base of each locule through the hollow stylar canal. Temporal separation occurs between male and female meiosis (protandry), and outbreeding is further promoted by terminal septal glands functioning as nectaries and the synchronized closure of the common carpellary cavity by inter-digitating papillae on the inner septal margins. This work was supported in part by the U.S.-Japan Cooperative Science Program Grant GF-41367, the Japanese Soceity for the Promotion of Science and Grant-in-Aid No. 934053 from the Ministry of Education, Japan.     

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.     

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.     

Morphology of the gynoecium and systematic position of the Ochnaceae

The gynoecium is syncarpous in all Ochnaceae. In the Ochnoideae carpels are peltate with a conventional cross-zone bearing one ovule, or, in Lophira , a very broad cross-zone with an horizontal ovular row. In Ochna and Brackenridgea , the style is gynobasic, each carpel develops transmitting tissue on its morphologically dorsal surface, and this tissue lines a canal or originates a solid inner strand in each carpel at style level. The style is tubular, with an inner cuticle, and compound, each component with its own transmitting tissue. In Ouratea the style is solid with a single compound transmitting strand. In Lophira and Elvasia the transmitting tissue seems to be developed by the morphologically ventral carpellary surfaces. Ovules are unitegmic with a bivalent integument.
In the Sauvagesioideae carpels are peltate, but with ovules above the cross-zones, on margins of the symplicate zone. In Euthemis , there is one ovule on each side of, and close to, each cross-zone. The single stylar canal is bounded by the morphologically dorsal carpellary surfaces. In Sauvagesia ovules occur on both sides of the cross-zones but most of them are above on carpel margins, as are all ovules of Cespedesia. The stylar canal of Sauvagesia is bounded by the ventral carpel surfaces, three strips of the outer surface passing inside at the sutures and developing into transmitting tissue. The stylar canal of Cespedesia is bounded by the dorsal carpel surfaces. The gynoecium of Wallacea has two epeltate carpels with a laminar placentation, the carpel margins being displaced on to the topographically ventral carpel surfaces with a row of ovules along each margin. Ovules are bitegmic.
The Ochnoideae, which shows relationships with the Rutaceae, Meliaceae, Simaroubaceae and Hippocastanaceae, is more advanced than the Sauvagesioideae, which clearly belongs in the Violales. The Ochnaceae is to be placed in the Violales.     

COMPARATIVE MORPHOLOGY OF THE CARPEL IN THE ROSACEAE VI. POMOIDEAE: ERIOBOTRYA,HETEROMELES, PHOTINIA,POURTHIAEA, RAPHIOLEPIS,STRANVAESIA

The pomoid genera, Eriobotrya, Photinia, Pourthiaea, Raphiolepis, Stranvaesia, and Heteromeles, have compound inflorescences and biovulate carpels which become papery at maturity. The carpels of all of these except Heteromeles are fused with one another. There are open sutures in the carpels of Heteromeles, Photinia, Pourthiaea, and Raphiolepis, and in these four genera the extent of fusion of the ovular bundle with the wing bundle is related directly to the state of tegumentary fusion and to the extent of fusion of the carpel with the floral cup. In those species of Eriobotrya and Stranvaesia with closed sutures the integuments tend to be fused, as do the ovular and wing bundles, and the carpels are adnate with the floral cup for a considerable distance; in species with open sutures the integuments tend to be free, the ovular and wing bundles tend to be separate, and the extent of fusion of carpel with floral cup tends to be shorter. In genera with connate carpels the wing bundles of adjoining carpels may also be fused. The greatest extent of fusion occurs in Eriobotrya and Raphiolepis, in which there may also be attenuation and disappearance of the wing bundles above the region of ovular insertion and even reduction and disappearance of the carpellary margin.     

Comparative morphology of the carpel in the Liliaceae: Uvularieae

Three genera of the Uvularieae (Kreysigia, Schelhammera, Uvularia) have tricarpellate, syncarpous pistils. Ventral bundles (presumably the united simple septal and placental bundles of a carpellary wing) may be present in Kreysigia and Schelhammera. In Kreysigia the two presumptive ventral bundles from adjoining carpels are fused basipetally in each septum. The septal bundles of the other two genera are either simple (Schelhammera) or in part compound (united) below and simple (separate) above (Uvularia) , hence fused acropetally. In Uvularia , the dorsal bundle of the carpel and the median bundle of the tepal are uniquely tripartite and probably homologous. No raphides were found in the carpels of these genera.     

Development of the gametophytes, flower, and floral vasculature in Cochliostema odoratissimum (Commelinaceae)

Flowers of Cochliostema odoratissimum are trimerous with three fertile stamens, three unequal antherless staminodes. and three connate carpels. The fertile stamens are on one side of die flower and united by their filaments, forming a compound structure that curves to the flower's right as the flower opens. The thecae arc longitudinally dehiscent, spirally coiled, and enveloped by pctaloid extensions of the filaments of the two lateral stamens contributing to the three-staminate structure. Anther wall development is of the monocotyledonous type. Tapetal raphides are formed and appear to be widespread in CCommelinaceae. Also known from Philydraceae and. perhaps. Haemodoraccae, tapetal raphides and their taxonomic distribution may be of phylogenetic utilitv. Microsporogcnesis is successive, forming both isobilateral and decussate tetrads. Pollen is shed as single binucleatc grains. Each ovary locule contains ten to twelve hemianatropous, crassinucellar. bitegmic ovules on axile placentae. The micropyle is formed by both the inner integument and one side of the outer integument. Megagamctophyte development is of the Polygonum type. The mature megagamctophyte consists of an egg apparatus, fusion nucleus, and three antipodals. the latter showing signs of degeneration. The salient features of the floral vasculature are the same as in the few other commclinaceous species for winch complete data are available. Relative to the floral vasculature in the other species, differences in the vasculature lie primarily in the presence and origin of lateral carpel bundles and in the number of sepal and ovule traces.     

Development of the gametophytes, flower, and floral vasculature in Dichorisandra thyrsiflora (Commelinaceae)

The flowers of Dichorisandra thyrsiflora (Commelinaceae) are monosymmetric and composed of three sepals, three petals, six stamens, and three connate carpels. The anthers are poricidal and possess a wall of five cell layers (tapetum included). This type of anther wall, not previously observed in the Commelinaceae, is developmentally derived from the monocotyledonous type via an additional periclinal division and the persistence of the middle layers through anther dehiscence. Secondary endothecial thickenings develop in the cells of the two middle layers only. The tapetum is periplasmodial and contains raphides. Microsporogenesis is successive and yields both decussate and isobilateral tetrads. Pollen is shed as single binucleate grains. The gynoecium is differentiated into a globose ovary, hollow elongate style, and trilobed papillate stigma. Each locule contains six to eight hemianatropous to slightly campylotropous crassinucellar ovules with axile (submarginal) placentation. The ovules are bitegmic with a slightly zig-zag micropyle. Megagametophyte development is of the Polygonum type. The mature megagametophyte consists of an egg apparatus and fusion nucleus; the antipodals having degenerated. The floral vasculature is organized into an outer and inner system of bundles in the pedicel. The outer system becomes ventral carpellary bundles. All other floral vascular traces originate from the inner system.     

Sporogenesis and gametogenesis of Delavaya toxocarpa (Sapindaceae) and their systematic implications

In order to investigate the embryological characteristics of Delavaya toxocarpa Franch. and provide a basis for further understanding the phylogeny within Sapindaceae s.l., we studied the sporogenesis and gametogenesis of D. toxocarpa using the conventional paraffin section method. The results were as follows: anthers are tetrasporangium; tapetum is typically secretory type; cytokinesis in the microsporecyte meiosis is of the simultaneous type and microspore tetrads are tetrahedral; mature pollen contains two cells; the ovary is bilocular with two ovules per locule; placentation is axial; the ovule is amphitropous, bitegmic, and crassinucellate; the chalazal megaspore in a linear tetrad becomes functional; and the development of megaspore is of the polygonum type. Most similarities shared by the species observed suggest that the species and genera of Sapindaceae s.l. have phylogenetic consistency. The distinctive trait, lacking hypostase, indicatesDelavaya (and Handeliodendron) might be more primitive than other genera in Sapindaceae. Moreover, some characters, such as opposite palmate compound leaf, apical thyrse, rounded seed without wing, 2 hemitropous ovules per locule, and lacking aril, indicate the close relationship between Delavaya, Aceraceae, and Hippocastanaceae. The preliminary data about the embryological and morphological characteristics in Delavaya might justify the basic systematic position of this genus in the family Sapindaceae s.s.