Opuntia humifusa Opuntia humifusa Opuntia humifusa, commonly known as the devil's-tongue, eastern prickly pear or Indian fig, is a cactus native to parts of eastern North America. As is the case in other "Opuntia" species, the green stems of this low-growing perennial cactus are flattened, and are formed of segments. Barbed bristles are found around the surfaces of the segments, and longer spines are sometimes present. The flowers are yellow to gold in color, and are found along the margins of mature segments. The flowers are waxy and sometimes have red centers. They measure 4–6 cm across. This cactus blooms in the
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