Floral morphology of southern African Orchideae. II. Habenariinae

The floral morphology of the southern African genera of Orchideae-Habenariinae (Bonatea, Cynorkis, Habenaria, Platycoryne, Stenoglottis, Centrostigma and Roe-perocharis) is surveyed paying special attention to the gynostemium. Ontogenetic data are provided for the species from which adequate material was available. It is shown that the floral architecture is essentially an elaboration and complication of that found in the better known Orchidinae. The structural similarities are particularly evident in the early ontogeny. Although the tribe Orchideae is commonly said to have gynostemia with erect anthers, a few Habenariinae are reported here to have reflexed anthers. In most cases both 'auricles' (filament excrescences) and 'basal bulges' (staminodes) are united to form the lateral gynostemium appendages. The primordia of both structures are clearly recognizable in the early ontogeny in all species studied. In Habenaria dregeana the basal bulges are only basally fused to the auricles, but in their main portion become adnate to the lip and petal bases: the auricles then solely form the lateral gynostemium appendages. It is suspected that this occurs also in other species not studied here. Systematic and phylogenetic aspects of the southern African representatives of the Habenariinae are discussed: the generic separation of Bonatea, Platycoryne and Centrostigma from Habenaria does not appear justified. Cynorkis, Roeperocharis and Stenoglottis are morphologically dissimilar to Habenaria. Based on the findings in the southern African taxa the status of the Habenariinae, Orchidinae, Orchideae and Diseae is discussed: there is no clear distinction between Habenariinae and Orchidinae; while the Diseae seem to represent a monophyletic group, the Orchideae are possibly polyphyletic.     

Floral morphology of the family compositae

Vernonia anthelmintica (Linn.) Willd., tribe Vernonieae, family Compositae has been studied. The cypsela has dimorphic pappus, 20 longitudinal ribs (10 primary and 10 secondary), and two types of hairs developing from single epidermal cells on surface. Certain features of vasculature of floret observed in this taxon have been considered as intermediate between relatively primitive and highly advanced conditions known in the family. Others elucidate further that the ovary is bilocular with axile placentation at base in which region the ovule is attached, and unilocular with parietal placentation in the remaining portion, and also that the ovule possibly belongs to one of the two carpels, which alone is fertile, and is an organ morphologically double in nature. The pappus has been regarded as a longitudinally dismembered calyx tube. The tissue of the ovule outside nucellus differentiates into an endothelium, a periendothelial zone, and an outer zone. In the mature seed the thickned outer epidermis and remmants of a few subjacent layers form the outer zone, and endothelium redued to a pellicle, the inner zone of the seed coat. The jacket layer of the endosperm persists between the seed coat and the dicotyledonous, orthorrhizal embryo. The pericarp development resembles that of most other Compositae in an early differentiation of the ovary wall into two zones, and later breakdown of a major part of the inner zone. But it is quite characteristic in other respects, especially, the peripheral chin of firovascular bundles which forms its main mechanical zone.     

Floral anatomy and morphology in thePolygalaceae

Floral morphology and anatomy of 15 genera in thePolygalaceae have been studied. The pentamerous origin of the polygalaceous flower is confirmed and shown to apply to all genera in the family. The keel is interpreted as a single petal, and the androecium as of bimeric origin. Vascular structure in the receptacles ofCarpolobia andMonnina subg.Monnina is described in detail, and a compilation of results, focusing on the vascular supply for the androecium and gynoecium, is given for all genera. Based on similarities and differences in vascularization it is concluded that present taxonomy, in particular the tribal system, needs to be reviewed.     

Floral morphology of wild and cultivated cowpeas

Some lines of one of the wild subspecies of cowpeas, Vigna unguiculata (L.) Walp. subspecies mensensis, which is characterized by large, conspicuous flowers, were found to set fruits poorly in the absence of a pollinator, whereas others, including cultivated lines, set well. These differences were related to the separation of anthers and stigma, the orientation of the stigmatic surface and the hairiness of the style, and differed from other outbreeding mechanisms reported in cowpeas. The results support division of wild cowpeas into two groups and suggest that an increase in the rate of inbreeding has accompanied their domestication.     

Morphogenesis in Cultured Floral Parts of African Violet

Callus tissue was induced from floral parts of African violetcultured on MS medium containing NAA (2 mg I^–1) and BAP(0.2 mg I^–1). When maintained on this medium in the presenceof light, the callus produced many shoots and roots. Large numbersof adventitious shoot buds were formed apparently in the absenceof callusing when ovary, sepal, and petal tissue was culturedon MS medium supplemented with BAP (1 mg I^–1) and NAA(1 mg I^–1). In contrast, culturing the same floral partson MS medium augmented with kinetin (1 mg I^–1) and NAA(0.5 mg I^–1) and NAA (0.5 mg 1-¹) led to the profuse developmentof roots. Organs seemed to be initiated from the epidermis ofcultured floral parts and did not appear to be related to particularcells or loci. Transfer of shoots to MS medium deviod of growthsubstances resulted in the formation of plantlets, which ata height of 3 cm could be transferred to soil and grown to maturitywithout variation in morophology or cytology.     

Floral morphology and ontogeny in Orchidaceae subtribe Disinae

Floral morphology and ontogeny in Orchidaceae subtribe Disinae. The flower structure and development of 24 species of the orchid subtribe Disinae are described and illustrated by drawings and scanning electron micrographs with special attention being paid to the gynostemium. The morphogenesis of this subtribe is fundamentally similar to that of the closely related tribe Orchideae. This includes the initiation of the auricles on the anther base in a dorsolateral position, and hence their interpretation as being mere appendages of the filament. The keel connecting the petals and the gynostemium plus its protrusion is considered homologous to the inner lateral staminodeS. Presumed vestiges of the adaxial staminodes were detected in one specieS. A peculiarity of the Disinae is that the entire apex of the median carpel develops into the rostellum, whereas its stigmatic portion emerges from the median carpel below the rostellum in later stages. The main diagnostic feature of the group is the reflexed position of the mature anther. However, it is shown here that this anther movement occurs in the later stages and that the initial anther is erect.     

Globin gene-associated restriction-fragment-length polymorphisms in southern African peoples.

The combination of polymorphic restriction-enzyme sites in the 3' region of the beta-globin gene cluster shows very little variation in southern-African Bantu-speaking black and Kalahari !Kung San populations. The sites of the 5' region, on the other hand, show marked variation, and two common haplotypes are present--the "Negro" type (- - - - +) and the "San" type (- + - - +)--in frequencies of .404 and .106, respectively, in the Bantu-speakers and .262 and .405, respectively, in the San. Twenty of 23 beta s-associated haplotypes in southern-African Bantu-speaking black subjects were the same as that found commonly in the Central African Republic (CAR)--i.e., the "Bantu" type--a finding providing the first convincing biological evidence for the common ancestry of geographically widely separated speakers of languages belonging to the Bantu family. The (-alpha) haplotype has a frequency of .21 in the Venda, .07 in both the Sotho-Tswana and the Nguni, and .06 among the !Kung San. These data are interpreted in the light of Plasmodium falciparum malaria selection and population movements in the African subcontinent.     

Pollinators,floral morphology and scent chemistry in the southern African orchid genus Schizochilus

Floral evolution often involves suites of traits, including morphology, colour and scent, but these traits are seldom analysed together in comparative studies. We investigated the associations between floral traits and pollination systems in Schizochilus, a southern African orchid genus with small nectar-producing flowers that has not been studied previously with respect to pollination biology. Field observations indicated the presence of distinct pollination systems in the four species which occur in the Drakensberg, including pollination by muscid flies in Schizochilus angustifolius, tachinid flies in Schizochilus zeyheri, various small flies in Schizochilus bulbinella and bees and wasps in Schizochilus flexuosus. Pollination success and pollen transfer efficiency clearly differed among the four species but were not correlated with the quantity of nectar rewards. Multivariate analysis of floral morphology and floral scent chemistry based on GC-MS data revealed significant differences among species as well as populations within species. The floral scent of S. angustifolius was dominated by the benzenoid compounds benzaldehyde and phenylacetaldehyde. Samples of one population of S. bulbinella were relatively similar to S. angustifolius but samples of another population were very distinct due to the occurrence of the nitrogen-containing compounds 3-methyl-butyl aldoxime (syn/anti) and the higher amounts of aliphatic esters, alcohols and acids. In contrast, the floral scent of S. flexuosus and S. zeyheri was characterized by high relative amounts of methyl benzoate. We conclude that Schizochilus has distinct, specialized pollination systems associated with subtle but significant variation in floral morphology and scent chemistry. We also caution that sampling of several populations may be required to characterize floral scent composition at the species-level in plants.     

Floral morphology and phylogenetic analysis inCrossostylis (Rhizophoraceae)

Floral morphology in all ten species ofCrossostylis, one of the inland genera of Rhizophoraceae and is distributed in the South Pacific Islands, was studied to increase our knowledge on floral features of individual species as well as on relationships among the species. Flowers ofCrossostylis, unlike those of the other Rhizophoraceae, always have semi-inferior ovaries and entire petals, but are diversified concerning the number and arrangement of stamens and carpels, the presence or absence of staminodia, sexuality and the structure of nectaries. Despite some doubt of the presence of apomorphies restricted to the whole genus, we tentatively definedCrossostylis by a combination of the presence of the semi-inferior ovary, entire petals, and arillate seeds, and then performed cladistic analysis on the basis of 24 floral and other morphological characters and withCarallia andGynotroches as outgroups. Our phylogenetic analysis suggested that the species ofCrossostylis are divided into two monophyletic groups: one comprising six species distributed in the Solomon Islands, Vanuatu and the Fiji Islands, and the other comprising four species distributed in New Caledonia and Polynesia.     

Floral development and morphology of Vochysiaceae. II. The position of the single fertile stamen

A conspicuous feature of Vochysiaceae flowers is their single fertile stamen. In some genera, the stamen is in front of a petal, whereas in others it is in front of a sepal. This difference has been attributed to two independent reductions, which implies the stamen is not homologous across the family. The observation that genera with an antesepalous stamen have only one petal, whereas those with an antepetalous stamen have three or five petals, led us to the hypothesis that in all genera the stamen arises in an antepetalous position, but that it is displaced during development in single-petaled taxa. We examined developing buds of five genera using scanning electron microscopy and serial sectioning and conclude that the stamen in all genera is fundamentally antepetalous. The stamen is not displaced. The petal, however, appears to be displaced in some genera. Further, the position of the fertile stamen in Erisma has been misinterpreted. We discuss the evolution of the androecium in this family in a phylogenetic context and consider the significance of symmetry and of loss vs. suppression in the development of Vochysiaceae flowers.     

Floral morphology and phylogeny of the Disinae (Orchidaceae)

Previous classification of the Disinae has been based almost entirely on floral morphological data. These data are critically assessed by various methods to determine to what extent they support a classification resolved to sectional level. The variation in the characters relative to the sections and genera is mapped, homologies are established by careful morphological observation and ontogenetic studies, and finally hypotheses of homology are tested by congruence in several cladistic analyseS. It is found that although floral morphology allows the recognition of some groups, for others the results are ambiguouS. Floral morphological data are clearly inadequate to establish the taxonomy of the Disinae on a sound footing.     

Floral morphology and late-acting self-incompatibility inApocynum cannabinum (Apocynaceae)

Scanning electron and fluorescence microscopy were used to clarify some aspects of the floral morphology ofApocynum cannabinum. Insects are required for pollination, since the floral morphology prevents autogamy and minimizes intrafloral self-pollination. Flowers hand-pollinated with self-pollen never set fruit, but 10.6% of cross-pollinations produced fruit. Self-pollen did germinate, however, and produced abundant tubes that grew through the pistil and entered the ovule micropyles. The proportion of ovules penetrated by self- and outcross-pollen tubes was not statistically significantly different. These results suggest thatA. cannabium possesses late-acting self-incompatibility, similar to that in the closely related Asclepiadaceae.     

Floral resources collected by four native bees species in southern Mexico

Abstract

Melissopalynological analysis of 14 honey samples of Tetragonisca angustula (two), Scaptotrigona mexicana (six), Melipona beecheii (three) and Melipona solani (three) from Soconusco region in Chiapas, Mexico was performed. A total of 79 taxa were identified, being Asteraceae, Euphorbiaceae, Fabaceae, Melostomataceae and Rubiaceae the predominant pollen types. Melissopalynological analysis reported a monofloral composition for Melipona beecheii honeys, where the most predominant pollen type was Fabaceae (54.2%). T. angustula, Scaptotrigona mexicana and Melipona solani honey samples were multifloral and predominant pollen types were Asteraceae, Euphorbiaceae, Fabaceae, Melastomataceae and Solanaceae. The most frequent polliniferous pollen type were Asteraceae, Bernardia interrupta, Euphorbia heterophyla and Miconia. Shannon–Wiener diversity index (H′) for Melipona beecheii 2016 (2.21) and Melipona solani 2017 (1.64) were lower meanwhile honeys of Melipona beecheii 2017, S. mexicana 2017, Melipona solani 2016 and T. angustula 2017 were considered as fairly diverse, because they visited a wider range of plant species, by preferring shrub and wild strata such as: Asteraceae, Euphorbia, Euphorbiaceae, Miconia and Mimosa. Our results showed that the foraging behaviour of these bee species is polylectic, as no taxa was found to be more than 70% of the counted grains. Since the study of the collection of meliponine flower resources in the southern region of Mexico have not been studied yet, it is not possible to analyse the foraging behaviour, the use of resources and the management of these species in this region.     

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.     

银缕梅属花形态及其分类学意义

以1995年在江苏宜兴发现的一较大银缕梅居群的花为材料,观察确认金缕梅亚科单种属银缕梅属（ShaniodendronM.B.Deng,H．T．WeietX．QWang）的花序为近头状短稳状花序,由4～7朵花组成,花序内轮4～5朵花,两性;外轮1～2朵花,常为雄花,构成雄全同株。花无柄,无花瓣,花喜常合成浅林状,杯缘及杯背早期簇生长硬毛（hirsute）,花生于初生苞片腋处,初生苞片卵形或阔卵形。雄蕊不定数,5～15枚,花丝长,直立。与其他无花瓣属植物比较表明,银缕梅属与特产里海南岸的Parrotia形态极为相似,主要区别在于本属花萼合生成浅怀状。银缕梅属花形态特征的阐明,对探讨金缕梅亚科无花瓣类群的系统发育具有重要意义。