The importance of the Soma-plant in Vedic religion has never been underestimated. Among the rituals of the Yajurvedic texts, the soma-sacrifices are among the most elaborate and important, and are described in minute detail in the Brāhmaṇas and Śrauta-sūtras. These later texts nevertheless continue a direct tradition from the Ṛgveda, which can be seen to reflect an earlier stage in the development of the ritual, doubtless of a less rigidly formalized and probably less elaborate nature. Even so, the Ṛgveda is, so to speak, permeated by Soma. Understandably, therefore, from the early days of Vedic studies in the West, many scholars have speculated on the botanical identity of the plant in question. Numerous candidates have been nominated, the most frequently favoured being species of the genera Ephedra, Sarcostemma, Periploca, and latterly Cannabis, and even Rheum. Not a single one of these conjectures has gained general assent, and the opinion is widely held that the problem is insoluble.