Salvia divinorum is a perennial herb in the Labiatae, which grows in the highlands of the Sierra Mazateca, Oaxaca, Mexico. One of almost 1,000 species of Salvia in the world, S. divinorum is recently discovered by western science, but has become rapidly well known for its hallucinogenic properties, but has also been researched for its unusual botanical characteristics.

Traditionally, the herb has been used in healing and divination among the Matazec of Oaxaca. The first introduction to S. divinorum came in 1938 when Jean B. Johnson, son-in-law of anthropologist Roberto Weitlaner, wrote about Hierba Maria in his publications about the Mazatec shamans (1939). In 1945, Blas P. Reko also found the magical plant among the Cuicatecs and Mazatecs which produced visions, referred to as “leaves of prophecy,” but could not identify the plant from the loose leaves collected. Weitlaner also conducted interviews concerning the magical plant, Yerba de Maria, but no identification was made until 1957, when Arturo Gomez-Pompa collected the plant while collecting mushrooms for the drug firm CIBA.

He obtained enough of the plant, called xka Pastora, to identify it as a Salvia sp; however, no flowering material was available, and Gomez-Pompa could not identify the plant further (Valdes 2001a). Finally, in 1962, Gordon Wasson and Albert Hoffman undertook the goal to find and definitively research the purported “magical” plant.

Hoffman, who had already discovered LSD and isolated psilopsybin and lysergic acid amides from mushrooms and morning glory seeds used by the Mazatec, joined with the leadership of self-styled ethnomycologist Gordon Wasson to traverse the Sierra Mazateca looking for S. divinorum, particularly in the wild. Wasson and Hoffman could not find independent populations of S. divinorum, but obtained the first flowering specimens of the plant from an old curandera, Natividad Rosa, in the village of San Jose Tenango. Wasson and Hoffman were not allowed to visit the location where the plants grew, leading Wasson to conclude that S. divinorum was probably a cultigen (Wasson 1962).

The specimens were identified as a new species of Salvia by Carl Epling and Carlos D. Jativa at the Botanical Institute of Harvard University in Cambridge, Massachusetts (Epling and Jativa 1962). S. divinorum is described as a perennial herb, mostly 1-1.5 m tall, with taller stems often decumbent, enabling plant to reproduce vegetatively by rooting at nodes and sometimes internodes, and to resprout vigorously from dry, senescent stem material. It has several characteristics related to other Salvia sp., including a quadrangular stem, serrated leaves situated oppositely on the stem, and sigmoidal flowers growing on tall racemes(Epling and Jativa 1962). However, it is highly distinctive and unusual among the Salvia species is certainly anomalous in sect. Dusenostachys Epl., to which it was originally assigned (Epling & Jativa 1962, Reisfield 1993).

According to Epling and Jativa, S. divinorum may be allied to S. cyanea Lamb ex. Benth, which is also found in central Mexico, but differs in the leaf shape and the flattened upper style branch (Epling and Jativa 1962). In the original description of S. divinorum, Epling (1962) described the plant as having a blue calyx tube and corolla, an error which persisted in someliterature, including the first edition of Emboden’s book Narcotic Plants and R.E. Shultes’ Hallucinogenic Plants, among others. Emboden was the first to correct this error, however, in his second edition of Narcotic Plants when he described S. divinorum’s corollas as “pure white” (Ott 1996).

The official description of S. divinorum was amended again by Reisfield in 1993, who described the reproductive parts of the plant in detail, including the nutlets, which are about 2 mm long and dark brown when viable. Distribution is limited to the highlands of Sierra Mazateca, where it grows at elevations of 300-1800 m in primary and secondary cloud forest or tropical evergreen forest. S. divinorum prefers to grow in the black soils along streambanks, where it spreads vegetatively in heavily shaded, moist ravines.

S. divinorum has also been found planted in coffee plantations, which are frequently blanketed in heavy fog, providing necessary humidity to grow. S. divinorum is usually anthropogenically distributed, grown in cultivated or semi-cultivated populations that are well hidden by the Mazatec, (Wasson 1962, Valdes 1983, 1987, Reisfield 1993).

Because of the Mazatec’s secrecy, ethnobotanists were unable to identify the plant for many years because they were not allowed to visit the growing sites, and flowering material was required for a definitive identification (Wasson 1962, Hoffman 1990). Since 1962, the botanical characteristics of S. divinorum have been studied in greater detail, particularly regarding its flowering and seed set. (Valdes 1982, 1983, 1987, Reisfield 1993).

By mapping the known Mexican populations of s. divinorum, Reisfield witnessed a few populations in flower, and discovered that while vegetative growth is promoted by cool, wet, shady environments, flowering is promoted by sunlight and may occur anytime from October to May in Mexican populations, though flowering occurs sporadically and infrequently. In Mazatecan populations, seed set has not been observed and all plants appear to be clonal (Reisfield 1993, Valdes 1987).

The nectar and dimensions of the S. divinorum flower suggest ornithophily, but the only pollination event observed in the wild involved a single hummingbird. It is believed, then, that pollination is opportunistic, rather than the result of a specialized plant-pollinator coevolution (Reisfield 1993). As a result, it is possible that many populations of S. divinorum are clonal, but this has not yet been investigated. Valdes asserted in 1987 that all S. divinorum in the United States at that time was cloned from the original specimens given to Epling, which was propagated at the University of California, Berkely.

Valdes and Reisfield investigated the reproductive qualities of S. divinorum using both collections from the forests of the Sierra Mazateca and clones from the original plants introduced by Hoffman and Wasson. In Valdes’ greenhouse experiments, newly collected plants from the field were crossed with the original clones. Of the 14 flowers cross-pollinated, 4 set seed (28%). Valdes was unable to test the viability of these seeds, however (Valdes 1987).

Reisfield performed both self-pollination studies and cross-pollination studies. Of the 432 potential seeds that could be formed from the 108 self-pollinations, only 11 nutlets developed (2.5%). Of the 190 cross-pollinated flowers, 24 nutlets developed (3%). Reisfield planted several mature seeds in the greenhouse, and “vigorous seedlings developed which were undistinguishable (though not grown to flowering) from their parents.” Reisfield further investigated the reproductivity of S. divinorum by experimentally observing that only 53% - 56% of pollen is viable, and adhesion to the stigma is poor. 33% of pollinated styles showed pollen germination and pollen tube growth, and pollen tubes appeared healthy, suggesting that the primary barrier to fertility is not inhibition of the pollen tube.

Reisfield suggested that the probably cause of infertility in S. divinorum, then, is post-zygotic embryonic abortion due to either inbreeding, hybridity, or a delayed self-incompatibility reaction. The abnormalities of S. divinorum seem most closely aligned to characteristics of hybridity; however, no two Salvia species have been found that show an obvious affinity to S. divinorum (Reisfield 1993). S. cyanea may be one potential progenitor (Epling and Jativa 1962), but this has not been tested, and no other Salvia species appear to be likely candidates. Reisfield concludes that S. divinorum may be a hybrid or an inbred cultigen, but asserts that the origin of S. divinorum is still a mystery (1993).