Having made this discovery, the team now wants to understand whether
angiosperms are either monophyletic -- which would mean Nanjinganthus represents a stem group giving rise to all later species -- or polyphyletic, whereby Nanjinganthus represents an evolutionary dead end and has little to do with many later species.
Indeed, we can see this macroscopically in samples of dried
angiosperm woods, where the surfaces of shrinkage cracks run parallel to rays ("checking").
Baum, "Establishment of polarity in
angiosperm lateral organs," Trends in Genetics, vol.
This study also indicated that deforestation and poplar industry along habitat loss, over grazing, unawareness, annual fire practices and exploitation of medicinal plants were the major threats to the
angiosperms of Rawalakot.
About 40-70% of
angiosperms are considered to be polyploids [14].
Evolutionary genomic analyses of ferns reveal that high chromosome number are a product of high retention and fewer rounds of polyploidy relative to
Angiosperms. Amer.
However, if allowance is made for ash in the 1997 FH material, none of the measured P fractions differed appreciably from those in samples from the
angiosperm conifer forests, in which net N[O.sub.3.sup.-] -N production readily occurred (Table 7; Parfitt et al.
Angiosperms have evolved a multitude of external dispersal adaptations, including wind (anemochory), water (hydrochory), animal (zoochory), and self-dispersal (autochory; Fenner, 1985).
The fossil record also suggests that by 75 million years ago many flowering plant families were well established, and some of these are common in today's
angiosperm flora including; birch (Betula), alder (Alnus), oak (Quercus), elm (Ulmus), sycamore (Platnus), basswood (Tilia), chestnut (Castanea), maple (Acer), beech (Fagus), sweet gun (Liquidamber), hickory (Carya), and Magnolia.
Despite being a very important ethno-medicinal
angiosperm species, due to many factors, it has now been restricted to small pockets of the Kashmir Himalaya.