Asplenium platyneuron plant. Similar buds have also been reported from the single-sorus spleenwort, "Asplenium monanthes". The species most similar to "Asplenium platyneuron" is the black-stemmed spleenwort, "A. resiliens". However, this stipe of this species is darker, and the pinnae are opposite, rather than alternate, along the rachis. Neither black-stemmed spleenwort nor the other pinnate American spleenworts have dimorphic fertile and sterile fronds. It might be confused with a young Christmas fern, "Polystichum acrostichoides", but that species is generally much larger and has a green, scaly stipe and rachis. It is very similar to Boydston's spleenwort, "Asplenium × boydstoniae", a backcross with Tutwiler's
The purpose of a system is what it does The purpose of a system is what it does The purpose of a system is what it does (POSIWID) is a systems thinking heuristic coined by Stafford Beer. Stafford Beer coined the term POSIWID and used it many times in public addresses. In his address to the University of Valladolid, Spain, in October 2001, he said "According to the cybernetician, the purpose of a system is what it does. This is a basic dictum. It stands for bald fact, which makes a better starting point in seeking understanding than the familiar attributions of good intention, prejudices about expectations, moral judgment,