Tempskya
Tempskya is an extinct genus of tree fern that lived during the Cretaceous period. Fossils have been found across both the Northern and Southern hemispheres. The growth habit of "Tempskaya" was unlike that of any living fern or any other living plant, consisting of multiple conjoined dichotomous branching stems enmeshed within roots that formed a "false trunk". Description. The trunk of "Tempskya" was actually a large collection of stems surrounded by adventitious roots. The false trunks can reach up to in height and up to in diameter. Small leaves grew from various points across the height of the trunk . This is in contrast to most tree ferns, where typically large leaves grow from the top of the trunk. Thin leaves have been discovered for the first time on "Tempskya wyomingense" specimens; the more commonly seen fossilized leaf bases show that they covered the upper part of the trunk. Hypothesized growth pattern. Examination of cross sections of various "Tempskya" specimens shows that those with the largest trunks have the smallest number of stems, and vice versa. From this, a possible growth pattern of "Tempskya" has been suggested: at the sporeling stage, "Tempskya" would consist of a single stem, which would  begin to branch off distally. A "mantle" of adventitious roots would then develop around the stems to support them. Later on, many of the stems would begin to decay, while the adventitious roots would still provide support and absorb water for the grown plant. This growth pattern has also been hypothesized for "Psaronius". Ecology. "Tempskya" is thought to have grown in lowland environments close to water, like wetlands and riverbanks. Taxonomy. The first fossils of "Tempskya" was originally described in 1824 as the "Endogenites erosa" by Stokes and Webb, who considered it to be a palm tree. The genus "Tempskya  was named by August Carl Joseph Corda in 1845, from specimens found in what is now the Czech Republic. The four species originally described by Corda were, in order: Tempskya pulchra", "Tempskya macrocaula", "Tempskya microrrhiza", and "Tempskya schimperi". "Tempskya" is the sole member of the family Tempskyaceae. The family has been placed in the order "Filicales", which is now split into a number of orders of leptosporangiate ferns. They have been suggested to members of Cyatheales, based on morphological similarities of the petiole and spores to some members of that order. Species. Most taxonomists divide "Tempskya" species into two groups , those with a simple cortex with only a parenchymatous inner cortex without sclerenchyma, while other species have an inner cortex with either discontinuous or continuous layers of sclerenchyma. Fossil sites. "Tempskya" finds were thought to be exclusive to the Northern Hemisphere until specimens were discovered in Argentina and Australia, in 2003 and 2005, respectively. "Tempskya" fossils have also been discovered in the Czech Republic ,2002 and Japan ,1986. "Tempskya" were frequently found fluvial deposited in gravel pits in Germany. Its origin is not clear, in part they came certainly from Czech sites