Floral morphology and development reveal extreme diversification in some species of Croton (Euphorbiaceae).

Floral diversity of Croton, the second largest genus in Euphorbiaceae, is currently under-explored. Several clades demonstrate an unusual floral morphology, e.g.

The interaction between heterochrony and mechanical forces as main driver of floral evolution.

Heterochrony acts as a fundamental process affecting the early development of organisms in creating a subtle shift in the timing of initiation or the duration of a developmental process. In flowers this process is linked with mechanical forces that cause changes in the interaction of neighbouring floral organs by altering the timing and rate of initiation of organs. Heterochrony leads to a delay or acceleration of the development of neighbouring primordia, inducing a change in the morphospace of the flowers.

Mechanical Forces in Floral Development.

Mechanical forces acting within the plant body that can mold flower shape throughout development received little attention. The palette of action of these forces ranges from mechanical pressures on organ primordia at the microscopic level up to the twisting of a peduncle that promotes resupination of a flower at the macroscopic level. Here, we argue that without these forces acting during the ontogenetic process, the actual flower phenotype would not be achieved as it is.

Gynoecium structure in Sapindales and a case study of Trichilia pallens (Meliaceae).

Sapindales is a monophyletic order within the malvid clade of rosids. It represents an interesting group to address questions on floral structure and evolution due to a wide variation in reproductive traits. This review covers a detailed overview of gynoecium features, as well as a new structural study based on Trichilia pallens (Meliaceae), to provide characters to support systematic relationships and to recognize patterns of variations in gynoecium features in Sapindales.

Unbuttoning the Ancestral Flower of Angiosperms.

A recent study using an extensive data set plus sophisticated analytical tools reconstructed a model of the ancestral angiosperm flower. Although attractive, it presents problems of homology assessment. We discuss its inconsistencies and endorse the use of a comparative model that integrates biological parameters as essential to elucidate floral evolution.

Correction to: Floral development of petaloid Alismatales as an insight into the origin of the trimerous Bauplan in monocot flowers.

The caption of Figure 5 was published incorrectly in the original publication of the article.

Floral development of petaloid Alismatales as an insight into the origin of the trimerous Bauplan in monocot flowers.

Monocots are remarkably homogeneous in sharing a common trimerous pentacyclic floral Bauplan. A major factor affecting monocot evolution is the unique origin of the clade from basal angiosperms. The origin of the floral Bauplan of monocots remains controversial, as no immediate sister groups with similar structure can be identified among basal angiosperms, and there are several possibilities for an ancestral floral structure, including more complex flowers with higher stamen and carpel numbers, or strongly reduced flowers.

Floral development of Berberidopsis beckleri - can an additional species of the Berberidopsidaceae add evidence to floral evolution in the core eudicots?

Background And Aims: Berberidopsis beckleri is one of three species of the family Berberidopsidaceae. The flower of Berberidopsis is unusual for core eudicots in being spiral with an undifferentiated perianth. In a previous study of the sister species B.

Floral anatomy and vegetative development in Ceratophyllum demersum: a morphological picture of an "unsolved" plant.

Premise Of The Study: The phylogenetic position of Ceratophyllum is still controversial in recent molecular analyses of angiosperms, with various suggestions of a sister group relation to all other angiosperms, eudicots, monocots, eudicots + monocots, and magnoliids. Therefore, the morphological characters of Ceratophyllum are important for resolving the phylogeny of angiosperms. In this study, we observed the detailed developmental anatomy of all lateral organs and their configurations to elucidate the floral development and phyllotactic pattern of Ceratophyllum demersum.

Floral development of Sabia (Sabiaceae): evidence for the derivation of pentamery from a trimerous ancestry.

Unlabelled: •

Premise Of The Study: Flowers of Sabiaceae diverge from basal eudicots in combining pentamery with superposed whorls of sepals, petals, and stamens and are therefore crucial in understanding origins of core eudicot flowers. Different hypotheses are tested using floral developmental evidence, whether the pentamerous flower is derived from a spiral, trimerous, or dimerous progenitor.•

Methods: The floral development of two species of Sabia was investigated with the scanning electron microscope to understand their unusual floral morphology and the origin of pentamery.

Anatomical features associated with water transport in imperforate tracheary elements of vessel-bearing angiosperms.

Background And Aims: Imperforate tracheary elements (ITEs) in wood of vessel-bearing angiosperms may or may not transport water. Despite the significance of hydraulic transport for defining ITE types, the combination of cell structure with water transport visualization in planta has received little attention. This study provides a quantitative analysis of structural features associated with the conductive vs.

Establishment of zygomorphy on an ontogenic spiral and evolution of perianth in the tribe Delphinieae (Ranunculaceae).

Background And Aims: Ranunculaceae presents both ancestral and derived floral traits for eudicots, and as such is of potential interest to understand key steps involved in the evolution of zygomorphy in eudicots. Zygomorphy evolved once in Ranunculaceae, in the speciose and derived tribe Delphinieae. This tribe consists of two genera (Aconitum and Delphinium s.

Perianth evolution in the sandalwood order Santalales.

Flowers of Santalales remain largely unexplored with several questions of homology unanswered despite the large size of the order. Morphological and ontogenetic floral studies have the potential to identify new informative characters. We studied floral development in species of Loranthaceae, Santalaceae, Opiliaceae, and "Olacaceae" with scanning electron microscopy to clarify the origin and evolution of the perianth in Santalales.

Floral developmental evidence for the systematic position of Batis (Bataceae).

Molecular phylogenies have associated Bataceae with Salvadoraceae and Koeberliniaceae in an expanded Brassicales. Despite a long taxonomic history, the knowledge of the flower of Batis is still fragmentary. The floral development of pistillate and staminate inflorescences of Batis maritima was investigated to understand homologies of floral structures and to discuss the phylogenetic position of Bataceae within the Brassicales.