STUDIES IN THE FLORAL ANATOMY OF POLYGALA (POLYGALACEAE)

Flowers of Polygala are irregular, each having three small and two long winglike sepals, three petals, eight stamens, and a bilocular ovary. These flowers have been considered pentamerous, and placentation has been subject to various interpretations. Development and anatomy of flowers of Polygala alba, P. lanceolata, and P. lutea were studied to see if evidence of pentamery and change in placentation could be found. These studies reveal no evidence of vestigial petals or stamens nor of vascular traces to organs that are missing in the three species studied. Neither are there abortive sporangia in the bisporangiate anthers. Observations on development of carpel primordia and on the vascular plan of mature carpels indicate that placentation is fundamentally parietal rather than axile. Speculation is offered as to the derivation of this type of placentation.     

STUDIES OF THE MONOTROPOIDEAE (ERICACEAE). FLORAL NECTARIES: ANATOMY AND FUNCTION IN POLLINATION ECOLOGY

The morphological and vascular characteristics of the nectaries of the species of the Monotropoideae (Ericaceae) reflect the morphology and declination of the flowers. These, in turn, are related to the pollination systems of the species. The nectaries of members of the Monotropoideae exhibit a range in form from slender, elongate projections, to short, stout ones, or to low ridges between the staminal bases.     

A SURVEY OF FLORAL ANATOMY IN ARACEAE

Flowers of 23 species representing six subfamilies of Araceae were studied by means of serial cross sections, special attention being given to vascular patterns and to taxa of supposed phylogenetic importance. Floral structure is shown to be extremely diverse with no unifying pattern common to all subfamilies. Conclusions include the following: (1) Lysichiton has a specialized gynoecial vascular pattern which differs from others encountered in the survey and which weighs against the primitive position attributed to this genus by Hutchinson. (2) Philodendron, with its multiple stylar canals, cannot have originated from subfamily Pothoideae, as Engler's phylogenetic concept would require of all Araceae; instead, it appears that several syncarpous evolutionary lines have evolved independently from extinct apocarpous members of the family. (3) In Acorus, stamens are introrse and dorsal carpellary bundles are lacking; these characters and others justify the recognition of Acorus as a separate subfamily Acoroideae. In addition, the survey revealed a peculiar deterioration of the inner ovary wall and the septa in several taxa, apparently a normal feature of floral development. Spathiphyllum solomonense Nicolson is described in an appendix.     

FLORAL PIGMENTATION STUDIES IN THE GENUS GOSSYPIUM. III. QUALITATIVE ANALYSIS OF TOTAL FLAVONOL CONTENT FOR TAXONOMIC STUDIES

Despite the potential contribution suggested from chromatographic studies of many groups, taxonomic conclusions based on paper chromatography alone may carry some inherent errors. In many instances chemical differences between taxa cannot be characterized by two-dimensional chromatography of crude extracts. Pigment diversity may go unnoticed in such a study, and conclusions based on simple chromatographic results may show too much similarity between the taxa being compared. The resolution of chromatographic separations of the often very complex mixtures encountered in crude plant extracts can be greatly improved by a preliminary column separation, and in this study a method of pigment analysis employing both preliminary column and subsequent paper chromatography is used. While it is usually impractical to identify all of the components of a flavonoid complex, each member should be characterized to the degree that it can be distinguished from all others. Here, the characterization of a component includes its rate of movement in the column, relative position and color under ultraviolet light on the chromatogram, the absorption spectrum in ethanol and the change in the absorption spectrum when a reagent is added to the ethanol which has a particular effect on the spectral properties of that flavonoid. With very few exceptions no one criterion of characterization is definitive for any component. More than 20 flavonoid pigments have been observed in the two tetraploid Gossypium species, G. barbadense and G. hirsutum. Only 10 of the constituents were common to the two species. The results of a previous study based on two-way paper chromatography of crude extracts makes the two species appear much more similar in flavonoid composition than is indicated by the more detailed column-paper chromatography presented here. The degree of difference between G. hirsutum and G. barbadense is surprisingly large in light of the generally accepted theory of their common origin. The value of chromatographic-chemotaxonomic studies is greatly increased if the chemical systems involved are characterized.     

MORPHOLOGICAL STUDIES OF THE NYMPHAEACEAE SENSU LATO. XVII. FLORAL ANATOMY OF ONDINEA PURPUREA SUBSPECIES PURPUREA (NYMPHAEACEAE)

Classification and phylogeny of the Nymphaeaceae are unresolved. This study provides floral anatomical data that will assist in elucidating generic interrelationships and systematic relationships to other taxa of angiosperms. The floral anatomy of Ondinea purpurea den Hartog subsp. purpurea has been examined utilizing light microscopy. The peduncle possesses stelar vascular bundle complexes and cortical vascular bundles. Cortical bundles terminate within the peduncle. Each bundle complex consists of 2 collateral bundles on the same radius, the inner bundle inverted; 2 protoxylary lacunae occur yet differ in structure and function. Progressing acropetally, the inner xylary lacunae become discrete mesarch strands surrounded centrifugally by a vascular cylinder formed by divisions and anastomosing of the bundle complexes. Together these become the massive receptacular vascular plexus. The plexus provides collateral traces to the floral organs. Each sepal receives 3 traces that separate from the plexus as 1–3 lateral traces. Petals are absent and no vestigial petal traces have been observed. Distally, the plexus forms several large strands of connate gynoecial and androecial traces termed the principal vascular bundles (PVBs). Ventral veins separate from the PVBs and the latter extend acropetally through the outer ovary wall. Branches of the ventrals and PVBs contribute to septal vascular reticula from which each ovule is supplied by one vascular bundle. Each stamen receives 1 trace from branches of the PVBs. The ventrals and PVBs terminate within the carpellary lobes. A comparative anatomical study is offered that supports the inclusion of Ondinea in the Nymphaeaceae sensu stricto.     

FLORAL ANATOMY OF KRAMERIA LANCEOLATA

The anatomy of each of the series of floral organs of Krameria lanceolata was examined. The sepals are characterized by three main veins each, an undifferentiated mesophyll, and stomata on the upper epidermis. The fleshy petals are distinguished by their numerous veins as well as by palisade-like epidermal cells on the outer surface. The three partially united petals have each a single vein and long, narrow epidermal cells similar to those on other floral organs. The stamens are united at their bases and bear tetra-sporangiate, conical anthers. The gynoecium includes a sterile and a fertile carpel. In the receptacle the veins to the sepals and petals are separated by a wide gap; those to the petals and stamens, by a narrow gap. Anatomical characteristics of the flower dissociate Krameriaceae from the legumes with which they have frequently been thought to be allied.