Meadowsweet rust gall Meadowsweet rust gall Triphragmium ulmariae is a species of fungus in the Sphaerophragmiaceae family. It causes meadowsweet rust gall, which develops as a chemically induced swelling, arising from the lower surface of the meadowsweet leaves. This common gall is caused by the foliar 'rust' fungus "Triphragmium ulmariae" (DC.) Link, 1825 . The fungus attacks the petioles and / or midribs of the perennial meadowsweet ("Filipendula ulmaria") plant, a member of the family Rosaceae, causing swelling and distortion. Sori develop with bright orange spores. The rust's spores reach the meadowsweet via air movements and are spread from the galls that develop
Multicellular organism somatic embryogenesis (e.g. land plants, most algae, many invertebrates). One hypothesis for the origin of multicellularity is that a group of function-specific cells aggregated into a slug-like mass called a grex, which moved as a multicellular unit. This is essentially what slime molds do. Another hypothesis is that a primitive cell underwent nucleus division, thereby becoming a coenocyte. A membrane would then form around each nucleus (and the cellular space and organelles occupied in the space), thereby resulting in a group of connected cells in one organism (this mechanism is observable in Drosophila). A third hypothesis is that as a