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Although the family Crassulaceae has a very wide global distribution range, the family has definite areas of high present-day species diversity. These include the southern Africa subcontinent, Mexico, and parts of southwestern North America, Mediterranean Europe, and parts of the Orient. Five of the c. 34 genera recognised in the Crassulaceae are represented naturally in southern Africa. These genera, Adromischus Lem., Cotyledon L., Crassula L., Kalanchoe Adans., and Tylecodon Toelken, are illustrated and briefly discussed with reference to their diversity and distribution ranges in the subcontinent and beyond. To familiarise the reader with the genus-rank diversity in southern African Crassulaceae, a pictorial gallery of southern African genera, excluding Kalanchoe, in the family is presented.

Pumpkins (Cucurbita moschata) are one of the most important economic crops in genus Cucurbita worldwide. They are a popular food resource and an important rootstock resource for various Cucurbitaceae. Especially, C. moschata is widely used as a rootstock for the commercial production of bloomless cucumbers in East Asia. Since the genetic diversity of the commercial rootstock varieties is narrow, there has been an increasing demand for the trait development of abiotic and biotic stress tolerance breeding. In this study, 2071 high-quality SNPs that were distributed evenly across 20 chromosomes of pumpkins were discovered through the genotyping-by-sequencing (GBS) analysis of 610 accessions of C. moschata germplasm with a global origin. Using these SNPs, various analyses of the genetic diversity and the population structure were performed. Three subgroups were clustered from the germplasm collection, which included East Asia, Africa, and America, and these areas were included the most in each subgroup. Among those groups, accessions from Africa and South Asia showed the highest genetic diversity, which was followed by the Mexico accessions. This result reflected that large gene pools that consist of various native landraces have been conserved in those of countries. Based on the genetic diversity, we finally constructed the C. moschata core collection, which included 67 representative accessions from the 610 germplasms. Five morphological traits that are important in commercial grafting and rootstock seed production, which include the cotyledon length, the cotyledon width, the hypocotyl length, the internode length, and the number of female flowers, were investigated for three years and used to confirm the validity of the core collection selection. The results are expected to provide valuable information about the genetic structure of the worldwide C. moschata germplasm and help to create new gene pools to develop genetically diverse rootstock breeding materials.

Seed dispersal by rodents has been understudied in Africa. Based on seed-removal experiments, the presence of seeds in burrows and caches, cotyledon burial of seedlings, and images from camera traps, we provide evidence that rodents (Cricetomys kivuensis) remove and hoard large seeds of Carapa grandiflora in Nyungwe National Park, Rwanda.

Our studies on the enigmatic genus Bienertia (Chenopodiaceae), with its C4 photosynthesis and lack of Kranz anatomy, led us to the discovery of a second species of this previously-supposed monotypic genus. The new species is named Bienertia sinuspersici after its main range around the Persian Gulf countries and the northern side of the Gulf of Oman. Bienertia sinuspersici occurs in hot climates and is a vicariant of Bienertia cycloptera, which is found at higher latitudes and elevations in temperate and cold deserts of the region. Like Bienertia cycloptera, the new species has unique chlorenchyma cells with dimorphic chloroplasts and single cell C 4 photosynthesis. However, it differs anatomically by having mostly one to two layers of chlorenchyma cells, versus two to three layers in Bienertia cycloptera. Furthermore, the new species has longer cotyledon leaves, larger seeds, larger flowers, and larger chromosomes, and differs in a set of micro-morphological features. All of this supports our conclusion that this widely distributed, novel plant is an overlooked new species. Bienertia sinuspersici grows well in very hot climates, under conditions which most species can barely tolerate. Its wide distribution indicates that its novel C 4 photosynthesis may confer advantages for CO2 fixation in these habitats not found in C4 species having con- ventional Kranz anatomy.

The aim with this study was to analyse the population dynamics of Saxifraga cotyledon, a rare, long lived herb, with semelparous rosettes. In Sweden, S. cotyledon grows in fragmented habitats at hi ...

Summary Resulting from a careful morphological analysis, seedlings of the genera Euryale, Victoria, Nuphar, Nymphaea and Barclaya (Nymphaeaceae) are shown to be dicotylar. They have no resemblance to any seedlings of the Monocotyledoneae . Descriptions in the literature, which show a monocotylar structure in nymphaeaceous seedlings are due to wrong interpretations of seedling organs.

Summary • Here we document phenotypic differences between serpentine and nonserpentine ecotypes of Collinsia sparsiflora, as well as patterns of selection in these contrasting soil habitats. • We transplanted the two parental ecotypes and experimental F2 hybrids into six field sites, and collected morphological, phenological and fitness data on emergent plants. To focus on edaphically mediated selection, rather than on pollinator-mediated selection, we used pollinator-exclusion cages. • Transplanted parentals of the two ecotypes showed genetic differentiation for floral traits, but not for phenological traits or cotyledon size. For the F2 hybrids growing on serpentine soils, there was significant directional selection on cotyledon size, flower size and flower shape. However, the pattern of selection did not differ significantly between serpentine and nonserpentine sites. • Overall, we did not see evidence for divergent selection on the two soil types. We conclude that differences in floral traits between the ecotypes do not reflect adaptation to physical conditions associated with soil type, and that there are unmeasured traits that must be contributing to ecotypic differentiation.

Wood of Pinus cembroides from 232 trees sampled in 23 localities throughout its range in the United States and Mexico has been analysed for monoterpenes. With a few exceptions the trees of the continental populations from the state of Hidalgo northward produced α-pinene as the main monoterpene. The majority of trees of the southern populations (subsp. orizabensis) from the state of Puebla and adjoining regions of the neighboring Veracruz and Tlaxcala produced 3-carene in appreciable amounts. The population from Baja California (subsp. lagunae) produced monoterpenes of the sabinene family (thujene, sabinene, γ-terpinene, terpinolene and p-cymene) as the main constituents. The variations in morphological characters, including number of needles per fascicle, number of stomatal rows in needles, number of resin canals in needles, as well as other characters of the internal needle morphology, needle length and thickness, needle retention, thickness of seed shells, bark and cone characteristics, rate of growth and cotyledon number either paralleled or did not contradict the chemical variations. The evolution of the southern populations (subsp. orizabensis) into a separate group most likely resulted from geographic separation and climatic differences, while the evolutionary separation of the Baja California trees (subsp. lagunae) was connected with northwestern movement of the California coastal region from Miocene onward and the formation of Sierra Madre Occidental resulting in separation of this population from the mainland populations by the gap of the Gulf of California and the coastal mountain ranges.

Observations have been made of cotyledon and leaves of beech, Fagus sylvatica L., with an emphasis on tracheary features. The organization of tissues, including a complex reticulate venation, is typical of many dicotyledons, but the reticulum contains few vein endings per areoles and this condition is probably not common in dicotyledons. This study compares the Madonie leaf vascular pattern with that of the Etna individuals and major venation results the same, but minor venation and areolation differs. We could conclude that tracheogenesis offers good support for the surveys of leaf populations in different ecological habitats and for the study of mechanical supports and long distance transport of water and solutes.