Sphagnum erect, leafy, branched gametophyte with chlorophyllose cells and hyaline cells. This stage dominates the environment where "Sphagnum" grows, obliterating and burying the protonema and eventually building up into layers of dead moss called peat. Carpets of living "Sphagnum" may be attacked by various fungi, and one fungus that is also a mushroom, "Sphagnurus paluster", produces conspicuous dead patches. When this fungus and other agarics attack the protonema, "Sphagnum" is induced to produce nonphotosynthetic gemmae that can survive the fungal attack and months later germinate to produce new protonema and leafy gametophytes. It is unknown whether the leafy stage can produce
What Is and What Should Never Be descending riff [of "What Is and What Should Never Be"] is amazing: It's like a bow is being drawn back, and then it releases. The rhythm of the vocals is almost like a rap. It's insane — one of their most psychedelic songs." This was also one of the first songs recorded by the band for which Robert Plant received writing credit. According to rock journalist Stephen Davis, the author of the Led Zeppelin biography "Hammer of the Gods: The Led Zeppelin Saga", the lyrics for this song reflect a romance Plant had with his wife's younger sister. "What Is