Physical dormancy (PY) in seeds/fruits, which is caused by the water-impermeable palisade layer, has long been considered a mechanism for synchronizing germination to a favourable time for seedling survival and establishment. Recently, a new hypothesis (crypsis hypothesis) was proposed as the main selective factor for the evolution of PY. However, there are some misconceptions in this hypothesis. Our objective is to critically evaluate the crypsis hypothesis and to point out that there are multiple adaptive roles of PY. The fundamental argument in the crypsis hypothesis, that PY evolved as an escape mechanism from predators, is not valid according to the evolutionary theory of Darwin. According to Darwin's hypothesis, variations (dormancy in our case) within a population occur randomly, i.e. there is no direct function of a variation at the time of its origin. Different selection pressures operating in the environment increase or decrease the fitness of individuals with the variation. Water-gap anatomy in seeds/fruits and phylogenetic relationships of species with PY suggest that PY has evolved several times in angiosperms. Thus, we argue that not only predatory pressure but also several other environmental pressures (e.g. proper timing of germination, ultra-drying of seeds, dispersal and pathogens) were involved in increasing the fitness of species producing seeds with PY. The significance of PY in the survival of the species under the abovementioned environmental pressures and other misconceptions of the crypsis hypothesis are discussed in detail.

Physical dormancy (PY) in seeds or fruits has been reported in 17 angiosperm families but not in basal angiosperms, magnoliids or gymnosperms. Here, we report PY in fruits (germination unit) of Cassytha filiformis, a parasitic species in the magnoliid clade. Moisture content of fruits ranged from 10% to 16%, and the seeds are orthodox (desiccation tolerant). Manually scarified fruits increased in mass >80% during imbibition, whereas untreated fruits increased <16%, via only a few fruits imbibing. Thus, the fruits are water impermeable. Dye did not penetrate the lignified palisade layer in the endocarp. Dye tracking of innately non-dormant fruits suggested that the carpellary micropyle is the water gap in C. filiformis fruits. Manual scarification broke dormancy of most, but not all, C. filiformis fruits. Thus, a high percentage of the germination units have PY and a low percentage PY + physiological dormancy. This is the first verified report of PY in the magnoliids; PY is now known to occur in four of the five major angiosperm clades. The evolutionary aspects of PY in Cassytha, an isolated genus in Lauraceae, are discussed.

A collar canker and dieback disease of tea has recently emerged in Sri Lanka. Isolation from cankers consistently yielded fusaria. Morphological characters and ITS and tef1 combined sequence analysis identified the selected isolates as members of Fusarium solani Species Complex Clade 3. Artificial inoculation to young and mature tea plants confirmed pathogenicity.

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Seed biology is foster for ecologically sound management of parasitic weeds. The seedling which is the first vegetative phase of a plant after the germination has particular importance in the study of seed biology. Distance of parasite from the host plant, and germination morphology are two important aspects in life cycle of a parasitic plant. However, the little attention has been given to the study of germination biology of Cassytha filiformis. Thus, my study was conducted to identify the radical anatomy, seedling morphology, and minimal distance of the host to successful attachment of C. filiformis.