Several of the substances originally placed in Schedule I are psychedelic drugs which are contained in natural plants and fungi (such as peyote and psilocybin mushrooms) and which have long been used in religious or healing rituals.
The Commentary notes the "Mexican Indian Tribes Mazatecas, Huicholes and Tarahumaras" as well as the "Kariri and Pankararu of eastern Brazil" as examples of societies that use such plants.

Article 32, paragraph 4 allows for States, at the time of signature, ratification or accession, to make a reservation noting an exemption for
plants growing wild which contain psychotropic substances from among those in Schedule I and which are traditionally used by certain small, clearly determined groups in magical or religious rites.

However, the official Commentary on the Convention on Psychotropic Substances makes it clear that psychedelic plants (and indeed any plants) were not included in the original Schedules and are not covered at all by the Convention.
This includes "infusion of the roots" of Mimosa tenuiflora (M. hostilis; which contains DMT) and "beverages" made from psilocybin mushrooms.
The purpose of Paragraph 4 of Article 32 was to allow States to "make a reservation assuring them the right to permit the continuation of the traditional use in question" in the case that plants were in the future added to the Schedule I. Currently, no plants or plant products are included in the Schedules of the 1971 Convention.

Commentary 32-12: It may be pointed out that at the time of this writing the continued toleration of the use of hallucinogenic substances which the 1971 Conference had in mind would not require a reservation under paragraph 4.
Schedule I does not list any of the natural hallucinogenic materials in question, but only chemical substances which constitute the active principles contained in them.
The inclusion in Schedule I of the active principle of a substance does not mean that the substance itself is also included therein if it is a substance clearly distinct from the substance constituting its active principle.
This view is in accordance with the traditional understanding of that question in the field of international drug control.
Neither the crown (fruit, mescal button) of the Peyote cactus nor the roots of the plant Mimosa hostilis [Footnote: "An infusion of the roots is used"] nor Psilocybe mushrooms [Footnote: "Beverages made from such mushrooms are used"] themselves are included in Schedule I, but only their respective active principles, mescaline, DMT and psilocybine (psilocine, psilotsin).

Commentary 32-13: It can however not be excluded that the fruit of the Peyote cactus, the roots of Mimosa hostilis, Psilocybe mushrooms or other hallucinogenic plant parts used in traditional magical or religious rites will in the future be placed in Schedule I by the operation of article 2, at a time at which the State concerned, having already deposited its instrument of ratification or accession, could no longer make the required reservation.
It is submitted that Parties may under paragraph 4 make a reservation assuring them the right to permit the continuation of the traditional use in question in the case of such future actions by the Commission.

Furthermore, in a letter, dated 13 September 2001, to the Dutch Ministry of Health, Herbert Schaepe, Secretary of the UN International Narcotics Control Board, clarified that the UN Conventions do not cover "preparations" of psilocybin mushrooms:
As you are aware, mushrooms containing the above substances are collected and abused for their hallucinogenic effects.
As a matter of international law, no plants (natural material) containing psilocine and psilocybin are at present controlled under the Convention on Psychotropic Substances of 1971.
Consequently, preparations made of these plants are not under international control and, therefore, not subject of the articles of the 1971 Convention.
However, criminal cases are decided with reference to domestic law, which may otherwise provide for controls over mushrooms containing psilocine and psiloc
Several of the substances originally placed in Schedule I are psychedelic drugs which are contained in natural plants and fungi (such as peyote and psilocybin mushrooms) and which have long been used in religious or healing rituals. The Commentary notes the "Mexican Indian Tribes Mazatecas, Huicholes and Tarahumaras" as well as the "Kariri and Pankararu of eastern Brazil" as examples of societies that use such plants.
Article 32, paragraph 4 allows for States, at the time of signature, ratification or accession, to make a reservation noting an exemption for
plants growing wild which contain psychotropic substances from among those in Schedule I and which are traditionally used by certain small, clearly determined groups in magical or religious rites.
However, the official Commentary on the Convention on Psychotropic Substances makes it clear that psychedelic plants (and indeed any plants) were not included in the original Schedules and are not covered at all by the Convention. This includes "infusion of the roots" of Mimosa tenuiflora (M. hostilis; which contains DMT) and "beverages" made from psilocybin mushrooms. The purpose of Paragraph 4 of Article 32 was to allow States to "make a reservation assuring them the right to permit the continuation of the traditional use in question" in the case that plants were in the future added to the Schedule I. Currently, no plants or plant products are included in the Schedules of the 1971 Convention.
Commentary 32-12: It may be pointed out that at the time of this writing the continued toleration of the use of hallucinogenic substances which the 1971 Conference had in mind would not require a reservation under paragraph 4. Schedule I does not list any of the natural hallucinogenic materials in question, but only chemical substances which constitute the active principles contained in them. The inclusion in Schedule I of the active principle of a substance does not mean that the substance itself is also included therein if it is a substance clearly distinct from the substance constituting its active principle. This view is in accordance with the traditional understanding of that question in the field of international drug control. Neither the crown (fruit, mescal button) of the Peyote cactus nor the roots of the plant Mimosa hostilis [Footnote: "An infusion of the roots is used"] nor Psilocybe mushrooms [Footnote: "Beverages made from such mushrooms are used"] themselves are included in Schedule I, but only their respective active principles, mescaline, DMT and psilocybine (psilocine, psilotsin).
Commentary 32-13: It can however not be excluded that the fruit of the Peyote cactus, the roots of Mimosa hostilis, Psilocybe mushrooms or other hallucinogenic plant parts used in traditional magical or religious rites will in the future be placed in Schedule I by the operation of article 2, at a time at which the State concerned, having already deposited its instrument of ratification or accession, could no longer make the required reservation. It is submitted that Parties may under paragraph 4 make a reservation assuring them the right to permit the continuation of the traditional use in question in the case of such future actions by the Commission.
Furthermore, in a letter, dated 13 September 2001, to the Dutch Ministry of Health, Herbert Schaepe, Secretary of the UN International Narcotics Control Board, clarified that the UN Conventions do not cover "preparations" of psilocybin mushrooms:
As you are aware, mushrooms containing the above substances are collected and abused for their hallucinogenic effects. As a matter of international law, no plants (natural material) containing psilocine and psilocybin are at present controlled under the Convention on Psychotropic Substances of 1971. Consequently, preparations made of these plants are not under international control and, therefore, not subject of the articles of the 1971 Convention. However, criminal cases are decided with reference to domestic law, which may otherwise provide for controls over mushrooms containing psilocine and psiloc
Convention on Psychotropic Substances