Lophophora williamsii

Propagation

Germination

Williamsii seeds lose 3-4% viability per year.[1]

Williamsii seeds are positive photoblastic, exhibiting 60% germination in light but 0% in darkness.[3] However, germination dose-dependently increases with shading (394, 265, 67.1 µMol/sec/m2 PAR; 15%, 30%, 46% germination) providing further evidence of shade preference in williamsii.[1] In-vitro germination with a PPF of 50 µmol/sec/m2 resulted in a germination rate of 68-75%.[2]

In-vitro germination begins in less than 7 days with more than half of the final count occurring between seven and fourteen days. The time for germination of half of the final count is approximately 11 days.¹[2]

[4] [2]

Vegetative

In-Vitro

[2]

Seeds may be disinfected by immersion in 70% ethanol for 1 min, then 25 min in 0.6% sodium hypochlorite solution + 0.08% Tween-20 (v/v), then rinsed 3 times with distilled water. No trials were conducted to determine the effect of disinfection on germination, but the final rates were comparable to the maximum obtained in other studies (68-75%).[2][1]

Williamsii seedlings germinated in various media grew to an average diameter of 3.25 mm at 49 days after sowing.²[2]

Cultivation

Harvest

[5] [6] [7] [8]

Yield

Soilless

Sand’s density adds substantial weight to soilless media. Without the retaining properties of clay/organics present in traditional soil mixes, sand will migrate with each irrigation to the bottom of cacti pots and even exit through drainage holes. These characteristics lead to many cacti growers abandoning sand in favor of akadama. The resultant media is light in weight with greater airspace. These media characteristics may lead to changes in the appearance and growth of williamsii.[11]

Soil

Fertilization

Temperature

Lighting

Pests

Ecology

[12] [13] [14] [5] [6] [7]

Morphology

[14] [5] [6] [7] [8]

Roots

Stem

Leaves

Inflorescence

Seeds

[3]

Phytochemistry

[13]

Infraspecific Variation

Biosynthesis

Distribution

Timecourse

Improvement

[14]

Identification

[14] [5] [6] [7]

Inheritance

Methods

[14] [5] [6] [7]

Grafting

[15]

History & Society

[16]

Work Log

21 Jan 2024

Finally finished making the sieves so work can continue.

I decided to use nonsterile media that is disinfected prior to mixing. This isn’t how media is typically used, but it cuts down on a lot of work and makes the disinfection more standardized.

Mineral media that (probably) isn’t affected by heat is put into individual bags and placed in a pressure cooker. The pot is brought to boil for two hours but not sealed. The organic media that might degrade with extended heating is microwaved one at a time until the internal temperature reaches 70-75°C. Since these are small bags that cool quickly, the procedure is repeated after 1 hour.

Disinfection protocol A: Atmospheric steam for 2 hr
Disinfection protocol B: microwave to 70-75°C; repeat after 1 hr

¿: 20/40 gradation

20 Jan 2024

I am having trouble deciding how to procede with sieving. Media properties depend on particle size as well as composition. Do I sieve media before or after mixing? Do I sieve the commercial media or leave as is?

Take the example of “coarse sand”. The composition and particle size varies widely between products and types. General purpose sand has huge particles and contains a lot of carbonates. Since I am already using oyster shell to test the effect of calcium carbonate, the carbonates in sand will be a confounding factor.

The most defined product is probably white pool filter sand which is entirely silica and graded 20/40. I could test particle size directly by comparing white filter sand to quartz grit. I think I’ll leave that for a different experimental series.

There is also the question of whether and how to sterilize the media. Do I mix each one first, then disinfect? Do I sterilize or pasteurize?

04 Jan 2024

I’m only experimenting with soilless mixes that can be easily repeated by anyone.

Independent tests:

1. Fox farm ocean forest/perlite 1:1 sifted 4mm.
2. commercial cacti soil

Unfortunately, due to the legal issues of germinating L. williamsii, I am forced to use one of the nonactive species as a substitute—L. diffusa, for example.

17 Dec 2023

Thinking more about germination trials

1. Peat 5, 10, 25%
2. Coir 5, 10, 25%
3. Perlite
4. Rice Hulls
5. Turface
6. worm castings (0, 5%)
7. greensand (5, 15 g/L)
8. coarse sand
9. char
10. granite; 0.2-8mm
11. oyster shell or limestone (none or low)
12. scoria
13. akadama
14. zeolite
15. pumice

• compare to storebought cacti soil
• compare to takeaway tek germination?
• retain samples for media testing
• use only RO water for irrigation and fertigation
• rinse and grade all materials
• pasteurize media (170-80°C)
• Ocean forest?

13 Dec 2023

Seedlings seem to be tolerant of a slightly higher organic component and greater water-holding capacity. Soil/pumice 1:1 has been used for seed starting.

05 Dec 2023

CEC

Greensand probably doesn’t help with nutrients but it does have ion exchange and water hold capabilities. This would be a suitable replacement for organics (coir or peat) without the drawback of extra carbon for microorganisms. Bentonite is also a potential replacement due to its high CEC but with the drawback of eventual disintegration. Likewise, vermiculite eventually compacts.

How to Use Greensand in the Garden recommends 2-3 Tbsp per gallon of potting media (11-17 g/L; assumed 90 lb/ft3 density).

ORGANIC FERTILIZERS AND NUTRIENTS 23: GREEN SAND recommends 5-20 lbs/yd3 (3-12 g/L).

Turface also holds considerable water.

Oil-dri is made from Fullers Earth (attapulgite). Some versions have the potential to degrade into mush. Similar results are probable with other clay-based absorbents: bentonite, clay cat litter, etc.

Char has the potential to be a good medium for beneficial microorganism growth. However, bacteria are unlikely to survive very long in dry cacti mixes.

So randomly:

• 50% Turface (sifted?)
• 20% rice hulls
• 20% perlite
• 5% coir/peat
• 2.5% worm castings
• 2.5% char
• 10 g/L greensand

All ingredients except greensand and worm castings are mixed and then flooded to remove fines.

04 Dec 2023

I have been thinking about growing media. There is no shortage of opinions on recipes. Some of the more exotic ones seem to derive heavily from Japanese bonsai culture.

Understanding the Ideal Soil Preferences for Cacti

Bibliography

1. Mandujano, Maria C. and García Naranjo, Alejandra and {Rojas-Aréchiga}, Mariana and Golubov, Jordan, Conservation Status, Germination, and Establishment of the Divine Cactus, Lophophora Williamsii (Lem. Ex Salm-Dyck) J. M. Coult., at Cuatro~Ciénegas, pp. 227--240, 2020. doi: 10.1007/978-3-030-44963-6_14. Abstract
   Lophophora williamsii, commonly known as “peyote” or “divine cactus”, has a wide distribution in the Chihuahuan Desert, but is under threat due to over-harvesting for religious ceremonies or psychedelic tourism, and many populations no longer exist. Natural populations can be rehabilitated or aided by sowing seeds or reintroducing specimens, which requires information on germination requirements and establishment conditions. We assessed seed germination and establishment to identify ecological factors that may determine the formation of seed banks, the effect of solar radiation on establishment, and seed aging after ex situ storage. This information can be used for conservation programs of peyote populations at Cuatro Ciénegas. Seeds collected from the wild and a sample of seeds kept for several years in a botanical garden’s germplasm collection were used for experimental trials. Germination experiments included seeds of different ages (1–9 years old) and three different light conditions. Germination decreased with seed age and was higher under shade mesh conditions. Peyote seeds remained viable for several years, which suggest they may form a seed bank as well as survive storage at room temperature (20 ± 2 °C), with a germination decay of up to 25\% indicating a loss of viability process. Although Cuatro Ciénegas Basin holds well preserved populations of the divine cactus, they may be threatened by biological and anthropogenic factors, so it is urgent to drive efforts towards the future conservation of this outstanding cactus.
2. {Cortés-Olmos}, C. and {Gurrea-Ysasi}, G. and Prohens, J. and {Rodríguez-Burruezo}, A. and Fita, A., In Vitro Germination and Growth Protocols of the Ornamental Lophophora Williamsii (Lem.) Coult. as a Tool for Protecting Endangered Wild Populations, Scientia Horticulturae, vol. 237, pp. 120--127, July 2018. doi: 10.1016/j.scienta.2018.03.064. Abstract
   Lophophora williamsii is an ornamental slow growth cactus highly appreciated by cacti growers and hobbyists. Its demand is often satisfied through illegal collection of wild plants and many populations are threatened with extinction. Thus, an efficient in vitro protocol without plant growth regulators will be of great interest for conservation purposes of this cactus. Eight different germination media, combining Murashige and Skoog medium (MS, full and half-strength), sucrose (20 and 30\,g\,L−1) and agar (8 and 10\,g\,L−1), were used to study germination rate, number of seedlings with areoles and initial seedling development. Germination rates among culture media only differed significantly in the first 14 days after sowing (DAS), reaching 67–75\% at the end of the assay (49 DAS). Remarkable interactions among media components were detected, and 20\,g\,L−1 sucrose and 8\,g\,L−1 agar combination gave the highest performance for both size and number of areoles. Following germination assay, a growth assay was conducted during 105 days using three growth media (GrM) at different sucrose concentration (15, 30 and 45\,g\,L−1) to evaluate the increase in seedling size and number of areoles. Regardless of their initial size, 15\,g\,L−1 sucrose provided the best results for both traits. Size increase was higher in the 4–5\,mm seedling group, while increase in areoles was greater in 2-3\,mm seedlings. It was possible to develop an in vitro protocol, in absence of plant growth regulators, which allows maximizing L. williamsii germination and growth during its first stages of development, which may increase the availability of plants in the market and avoid exhaustion of wild populations. Furthermore, plants grown ex situ could be reintroduced in endangered natural populations.
3. {Rojas-Aréchiga}, Mariana and Mandujano, María C. and Golubov, Jordan K., Seed Size and Photoblastism in Species Belonging to Tribe Cacteae (Cactaceae), Journal of Plant Research, vol. 126, no. 3, pp. 373--386, May 2013. doi: 10.1007/s10265-012-0526-2. Abstract
   The response of seed germination towards light and the relationship to seed traits has been studied particularly well in tropical forests. Several authors have shown a clear adaptive response of seed size and photoblastism, however, the evolutionary significance of this relationship for species inhabiting arid environments has not been fully understood and only some studies have considered the response in a phylogenetic context. We collected seeds from 54 cacti species spread throughout the tribe Cacteae to test whether there was correlated evolution of photoblastism, seed traits and germination using a reconstructed phylogeny of the tribe. For each species we determined the photoblastic response under controlled conditions, and seed traits, and analyzed the results using phylogenetically independent contrasts. All studied species were positive photoblastic contrasting with the basal Pereskia suggesting an early evolution of this trait. Seeds from basal species were mostly medium-sized, diverging into two groups. Seeds tend to get smaller and lighter suggesting an evolution to smaller sizes. No evidence exists of a relationship between seed size and photoblastic response suggesting that the photoblastic response within members of this tribe is not adaptive though it is phylogenetically fixed and that is coupled with environmental cues that fine tune the germination response.
4. Cheib, Ana Loureiro and Garcia, Queila Souza, Longevity and Germination Ecology of Seeds of Endemic Cactaceae Species from High-Altitude Sites in South-Eastern Brazil, Seed Science Research, vol. 22, no. 1, pp. 45--53, March 2012. doi: 10.1017/S0960258511000298. Abstract
   The influence of light and temperature on germination behaviour and the longevity of seeds were evaluated in four taxa of the genus Arthrocereus (Cactaceae). Germination experiments were conducted at six constant temperatures with a 12-h photoperiod and in continuous darkness. For in situ storage tests, the seeds were buried in the soil where the species naturally occur, and germination experiments were performed for 14 months. Seeds were also stored dry at room temperature in the laboratory for 12 months. The results indicated that, in spite of the variations between the four taxa studied, there is a consistent pattern in their germination behaviour. The seeds are small, with an absolute requirement of light for germination. In the presence of light, we obtained high germinability at temperatures between 20 and 30°C and low germination percentages at 10, 15 and 35°C. This behaviour may represent an adaptive mechanism during seasons when environmental conditions in open rocky fields are not favourable for seedling survival. In general, germination was relatively slow, which would favour establishment during the rainy season. Dry storage did not significantly alter seed germination behaviour, and buried seeds, likewise, remained viable and retained high germination percentages. We can therefore infer that the seeds of the species studied here are able to form persistent soil seed-banks. All studied species are threatened with extinction, so their ability to form soil seed-banks, together with the possibility of ex situ seed preservation, will possibly give support for future conservation efforts.
5. Terry, M. and Trout, K. and Williams, B. and Herrera, T. and Fowler, N., Limitations to Natural Production of Lophophora Williamsii (Cactaceae) I. Regrowth and Survivorship Two Years Post Harvest in a South Texas Population, undefined, 2011. url: https://www.semanticscholar.org/paper/Limitations-to-natural-production-of-Lophophora-I.-Terry-Trout/dd1d7b7e4b4842c842030733ec34ac27ee1d08da. Abstract
   Reducing the frequency of harvesting of wild peyote would allow regrowth crowns to mature in size—thus reducing the number of crowns per dose required for sacramental consumption and de-suppress the production of seed for the next generation. Lophophora williamsii (peyote) is a cactus whose crowns are commercially harvested for religious use as an ingested psychoactive sacrament by members of the Native American Church. Over the past quarter century peyote has become progressively less available, due in part to improper harvesting techniques and excessive harvesting. Since anatomical aspects of the regrowth of peyote and best harvesting practices were explicated in a previous study (Terry \& Mauseth 2006), the principal focus in the present study was to determine the effects of harvesting where only best practices were employed. We assessed the effects of (1) harvesting per se (a single harvesting event evaluated after two years), (2) repeated harvesting (two harvesting events two years apart), and (3) not harvesting at all. After two years, the once-harvested group had a 90\% survival rate and the unharvested control group had a 98\% survival rate, a difference that was not statistically significant. The above-ground volume of the unharvested plants was significantly larger than that of the regrown harvested plants. While the regrown harvested plants had on average more crowns, their crowns were significantly smaller, in comparison to those of the unharvested plants. After two years, the surviving plants in the harvested group were divided into two subgroups, one of which was harvested for a second time. The other subgroup consisted of plants that had been harvested only once (at the start of the study) and were not reharvested. The weights of the crowns obtained in the second harvest were significantly lower than the weights of the crowns obtained in the first harvest from the same plants two years earlier. The net effect of a single harvesting was a reduction of plant above-ground volume by almost 80\% after two years of regrowth. These data reflect what is occurring on a massive scale in habitat where peyote is commercially harvested. The annual numbers of crowns being harvested have not yet decreased drastically, due to the increased number of crowns produced as regrowth in response to harvesting. But the average size of the crowns in the regulated peyote market has decreased markedly due to too-early harvesting of immature regrowth crowns. These results—with emphasis on the conspicuous reduction in mean size of individuals—are typical of overharvested populations of wild-collected species, such as ginseng. The conclusion for conservation management is that reducing the frequency of harvesting of wild peyote would allow regrowth crowns to mature in size—thus reducing the number of crowns per dose required for sacramental consumption. It would also allow regrowth crowns to mature sexually, which would effectively de-suppress the production of seed for the next generation.
6. Terry, M. and Trout, K. and Williams, B. and Herrera, T. and Fowler, N., Limitations to Natural Production of Lophophora Williamsii (Cactaceae) Ii. Effects of Repeated Harvesting at Two-Year Intervals in a South Texas Population, undefined, 2012. url: https://www.semanticscholar.org/paper/LIMITATIONS-TO-NATURAL-PRODUCTION-OF-LOPHOPHORA-II.-Terry-Trout/cc8119783e71102d6842739718ea88a4cc66c195. Abstract
   Trends and results indicate that present rates of peyote harvest are unsustainable, including harvesting treatments similar to those used to harvest it for legally protected religious use by members of the Native American Church. In 2008 we began a long-term study of the effects of harvesting on a wild population of the cactus Lophophora williamsii (peyote), including harvesting treatments similar to those used to harvest it for legally protected religious use by members of the Native American Church. Here we assess the effects of harvesting in three different treatments: (1) plants that were harvested once, (2) plants that were harvested every two years (typical of commercial harvesting rates), and (3) control plants that were never harvested. After four years, the survival rate was significantly greater in the unharvested control plants (94\%) than in the harvested plants (73\%). Average harvested mass of fresh tissue per plant decreased significantly (by 44\%) between the first and second harvests, and then further decreased significantly (by 32\%) between the second and third harvests. The average number of crowns per plant, which increased after the first harvest, decreased after the second harvest. Estimated total volume of the above-ground crown(s) of each plant, which was closely related to harvested plant mass, was used to compare growth rates between treatments. The average growth rate of the multiple-harvest plants was significantly lower than the average growth rates of plants in the other two treatments. Growth rates in the control and single-harvest treatments did not differ significantly in 2012, but because the single-harvest plants were so much smaller than the control plants in 2010, they remained smaller than the control plants in 2012. The annual number of crowns harvested and sold commercially as “buttons” by licensed peyote distributors continued its slow decrease in 2011, while the price per unit continued to rise. These trends and the results of this study all indicate that present rates of peyote harvest are unsustainable. key wordS: cactus conservation, peyote harvest, cactus overharvesting, Native American Church, peyote conservation status
7. Terry, M. and Williams, B. and Trout, K. and Herrera, T. and Fowler, N., Limitations to Natural Production of Lophophora Williamsii (Cactaceae) III. Effects of Repeated Harvesting at Two-Year Intervals for Six Years in a South Texas (U.S.A.) Population, Journal of the Botanical Research Institute of Texas, vol. 8, no. 2, pp. 541--550, 2014. url: https://www.semanticscholar.org/paper/Limitations-to-natural-production-of-Lophophora-of-Terry-Williams/7d060b3fb889a793d90a7aeb8b219478076eaf82. Abstract
   The results of this study indicate that a six-year recovery period, following the harvesting of peyote in natural habitats, is probably not long enough to ensure long-term sustainability. Here we report the 6-year results of a long-term study of the effects of harvesting on a wild population of the cactus Lophophora williamsii (peyote). Harvesting was performed using the best known technique: removing only the crown from the top of the plant. The two-year interval between harvests was chosen because it was similar to that observed by persons who harvest peyote for legally protected religious use by members of the Native American Church. Plants in the study were divided into three treatment groups: (1) control plants that were never harvested, (2) plants that were harvested only once, at the beginning of the study, and (3) plants that were harvested at the beginning of the study and every two years thereafter. Over the last two years of the study (2012‒2014), the survival rate was significantly lower (77\%) in the plants harvested every two years than in the once-harvested plants (100\%) and the unharvested control plants (98\%). At the end of the 6th year of the study, average volume of living crown tissue per plant was significantly and substantially lower in the plants harvested every two years than in the once-harvested plants and the unharvested controls. The average volume of once-harvested plants was 27\% lower than that of the controls, although this latter difference was not statistically significant. The modal number of crowns per plant varied with treatment and over time; in the plants harvested every two years it underwent a progression from 1 to 2 to 3 to 1 in response to successive harvests. The results of this study indicate that a six-year recovery period, following the harvesting of peyote in natural habitats, is probably not long enough to ensure long-term sustainability. key words: cactus conservation, peyote harvest, cactus overharvesting, Native American Church, peyote conservation status
8. Terry, M. and Mauseth, J., Root-Shoot Anatomy and Post-Harvest Vegetative Clonal Development in Lophophora Williamsii (Cactaceae: Cacteae): Implications for Conservation, undefined, 2006. url: https://www.semanticscholar.org/paper/ROOT-SHOOT-ANATOMY-AND-POST-HARVEST-VEGETATIVE-IN-Terry-Mauseth/6e141e67e86ab981b73dffe76e308e3e76c48a70. Abstract
   With these new anatomical tools, it is now possible to set up titration experiments, first in the greenhouse and then in the field, to generate practical biometric data to determine the maximum depth at which the peyote harvesters can cut the plants without significantly reducing the survival rate of the rootstocks left in the ground after harvest. Over the last four decades, the size and density of populations of Lophophora williamsii (peyote) have diminished markedly in large areas of South Texas where licensed peyote distributors harvest the cactus for ceremonial use by the Native American Church. Part of the problem lies in the fact that some harvesters are cutting plants too low on the subterranean stem or taproot. That practice precludes the regeneration of new stems and ultimately results in the death of the decapitated plants. To address this problem, we describe the anatomical distinctions between subterranean stem and root in L. williamsii as follows: The stem cortex can be distinguished by the cortical bundles running through the parenchyma, in contrast to the root cortex, which consists of pure parenchyma without cortical bundles. The pith at the center of the stem is pure parenchyma (without xylem) and is readily distinguished from the dilatated metaxylem (with masses of dark-staining metaxylem tracheary elements) occupying the center of the root. With these new anatomical tools, it is now possible to set up titration experiments, first in the greenhouse and then in the field, to generate practical biometric data to determine the maximum depth at which the peyote harvesters can cut the plants without significantly reducing the survival rate of the rootstocks left in the ground after harvest.
9. {San Pedro Mastery}, Perfect Peyote Soil Mix Part 1 - Lophophora Williamsii Soil Recipe, April 2019. url: https://www.youtube.com/watch?v=hwnhkg7Lq88. Abstract
   In this video, I share with you 2 soil recipes for growing the Peyote (Lophophora Williamsii) from seeds, as well as for repotting it. This is Part 1. Please also check Part 2. ---------------------------------------------------------------------------------------------------------- If you are interested in buying pure, well identified San Pedro seeds and seedlings, as well as San Pedro relatives, please email me at: sanpedromastery@protonmail.com If you have a question, I will only reply to questions about cultivation. Please no questions about the psychedelic properties of these cacti.
10. {San Pedro Mastery}, Perfect Peyote Soil Mix Part 2 - Lophophora Williamsii Soil Recipe, April 2019. url: https://www.youtube.com/watch?v=DZgiwDXmLv8. Abstract
    This is the Part 2 of "Perfect Peyote Soil Mix", with another recipe including coco coir, earthworm castings and limestone. ---------------------------------------------------------------------------------------------------------- If you are interested in buying pure, well identified San Pedro seeds and seedlings, as well as San Pedro relatives, please email me at: sanpedromastery@protonmail.com If you have a question, I will only reply to questions about cultivation. Please no questions about the psychedelic properties of these cacti.
11. {San Pedro Mastery}, Peyote Soil Update (Lophophora Williamsii Soil Mix Recipe), January 2022. url: https://www.youtube.com/watch?v=iJRcrP0DRAM. Abstract
    In this video I show you the changes I have made in my peyote soil mix in the past couple of years. ---------------------------------------------------------------------------------------------------------- If you are interested in buying pure, well identified San Pedro seeds and seedlings, as well as San Pedro relatives, please email me at: sanpedromastery@protonmail.com (Please mention your country when you email me) If you have a question, I will only reply to questions about cultivation. Please no questions about the mind expanding properties of these cacti.
12. Ermakova, Anna and Whiting, Carolyn V. and Trout, Keeper and Clubbe, Colin and Terry, Martin K. and Fowler, Norma, Densities, Plant Sizes, and Spatial Distributions of Six Wild Populations of Lophophora Williamsii (Cactaceae) in Texas, U.s.a, pp. 2020.04.03.023515, August 2020. doi: 10.1101/2020.04.03.023515. Abstract
    Lophophora williamsii (Cactaceae) is thought to be threatened by habitat loss and overharvesting. However, basic demographic and habitat information to evaluate its conservation status has been lacking. We surveyed six wild populations of this species, three in South Texas and three in West Texas, to begin to address this gap. We found high levels of heterogeneity in plant presence and density at multiple spatial scales. While plant densities were not consistently different between South and West Texas, plants were significantly larger in West Texas. The two regions differ strongly in precipitation, temperature, elevation, and topography, all of which are correlated at the regional scale. Therefore, it was not possible to identify which of these variables, or other factors such as competition and human harvesting, may be responsible for the regional differences in plant size. However, our results provide initial information for determining the conservation status of this species. RESUMEN Lophophora williamsii (Cactaceae) se considera amenazada por la pérdida de hábitat y cosecha excesiva. Sin embargo, se carece de información demográfica y ambiental básica para evaluar su estado de conservación. Para abordar este déficit, examinamos seis poblaciones salvajes de esta especie (tres en el sur y tres en el oeste de Texas respectivamente). Encontramos altos niveles de heterogeneidad en la presencia y densidad de plantas en múltiples escalas espaciales. Las densidades no son consistentemente diferentes entre el sur y el oeste, pero las plantas son significativamente más grandes en el oeste. Las dos regiones difieren notablemente en precipitación, temperatura, elevación y topografía. Todas estas variables están correlacionadas a escala regional, por lo que no es posible identificar cuál de ellas (u otros factores como la competencia y la cosecha humana) causan las diferencias regionales observadas en el tamaño de la planta. Nuestros resultados proporcionan información fundamental para determinar el estado de conservación de esta especie.
13. Hulsey, Diana and Kalam, M. and Daley, P. and Fowler, N. and Terry, M., Clinal Geographic Variation in Mescaline Concentration among Texas Populations of Lophophora Williamsii (Cactaceae), undefined, 2011. url: https://www.semanticscholar.org/paper/Clinal-geographic-variation-in-mescaline-among-of-Hulsey-Kalam/fb1b3089086601ef3571485bd68907becdd6185b. Abstract
    A phytochemical analytical study was conducted to address the question of whether Lophophora williamsii (peyote) plants from Chihuahuan Desert populations in the Trans-Pecos region of West Texas exhibited higher tissue concentrations of mescaline than plants from Tamaulipan Thornscrub populations of South Texas. A phytochemical analytical study was conducted to address the question of whether Lophophora williamsii (peyote) plants from Chihuahuan Desert populations in the Trans-Pecos region of West Texas exhibited higher tissue concentrations of mescaline than plants from Tamaulipan Thornscrub populations of South Texas. This question is of cultural significance to the Native American peyote religion, which involves the ingestion of peyote as a psychopharmacologically active sacrament. Tissue samples were field-collected from 10 individuals in each of four L. williamsii populations, two of which were located in the Chihuahuan Desert, and two of which were located in the Tamaulipan Thornscrub ecoregion. For each of the four populations, the tissue samples from 10 individual plants were pooled, the alkaloids were extracted, and the average mescaline concentration of the population was determined by HPLC. There was limited geographic variation in mescaline concentration; the highest concentration (3.52\% of dry tissue) was only 27\% greater than the lowest (2.77\%), and the difference between the Chihuahuan Desert populations and the Tamaulipan Thornscrub populations was not significant. However, mescaline concentrations increased significantly along a gradient from southeast to northwest, i.e., from the southeasternmost Tamaulipan Thornscrub population to the northwesternmost Chihuahuan Desert population.
14. {Briseño-Sánchez}, María Isabel and {Martínez-Peralta}, Concepción and Mandujano, María C., Population Structure and Reproductive Biology of Peyote (Lophophora Diffusa, Cactaceae), a Threatened Species with Pollen Limitation1,2, The Journal of the Torrey Botanical Society, vol. 147, no. 3, pp. 243--257, November 2020. doi: 10.3159/TORREY-D-18-00055.1. Abstract
    Threatened species frequently have a J-shaped population structure, which indicates a reduction in seed set and poor or nonexistent recruitment. Altered population structures may be due to disrupted demographic processes that result in low reproductive success or small population size. Peyote—Lophophora diffusa Croizat (Bravo)—is a rare, threatened cactus species that is subject to overexploitation because of psychedelic tourism and medicinal and religious uses that decrease its effective population size. We analyzed peyote population structure and identified attributes of its reproductive biology that may limit population persistence. The population's size structure (based on plant size in square centimeters) was determined by census in 2014 and 2015 (n = 420 individuals). Determination of the breeding system of peyote was based on floral morphology and evaluation of herkogamy, dichogamy, and pollen/ovule ratio, and controlled pollination experiments were used to determine the outcrossing rate and whether the species was pollen limited. Additionally, behavior and frequency of floral visitors were recorded to establish the pollinator guild. Peyote's population structure showed the presence of seedlings, juveniles, and adults in both years, indicating some recruitment and low adult mortality. Flowers were herkogamous, homogamous, and diurnal, with a 2-day longevity and high pollen/ovule ratios. These floral traits suggest that peyote is xenogamous, and pollination experiments indicated that it is a facultative outcrossing species, which needs pollinators to set fruit. The time of pistil receptivity coincided with the maximum activity of floral visitors (small solitary bees and small beetles) searching for floral rewards. Evidence indicates that peyote has an outcrossing system with partial self-incompatibility and is pollen limited. Positive factors, such as moderate seedling recruitment, a similar population structure during the two study periods, and a large number of reproductive individuals (close to 50\%), indicate natural regeneration and increase the likelihood of population persistence. However, low fruit set and strong dependence upon efficient pollinators reduce reproductive success and increase species vulnerability.
15. Monzer, J. and Kollmann, R., Vascular Connections in the Heterograft Lophophora Williamsii Coult. on Trichocereus Spachianus Ricc., Journal of Plant Physiology, vol. 123, no. 4, pp. 359--372, May 1986. doi: 10.1016/S0176-1617(86)80096-7. Abstract
    Vascular connections and symplastic contacts between the heterospecific cells in the graft Lophophora williamsii on Trichocereus spachianus are described. Xylem and phloem connections are mainly established during secondary growth by joint cambial activity of stock and scion. Xylary connections within the graft are characterized by species-specific secondary wall thickenings. There are interspecific plasmodesmata linking stock and scion parenchyma cells. Based on the reliable identification of xylem elements and parenchyma cells of the partners, circumstantial evidence is presented for the occurrence of a symplastic sieve element connection between stock and scion.
16. Terry, M. and Trout, K., Cultivation of Peyote: A Logical and Practical Solution to the Problem of Decreased Availability, undefined, 2013. url: https://www.semanticscholar.org/paper/Cultivation-of-Peyote%3A-a-logical-and-practical-to-Terry-Trout/de3dcb70ff29152ed61c66e7167d829ddebc28ad. Abstract
    Current and evolving aspects of the regulatory environment and emerging perceptions regarding the need for U.S. federal regulations that would provide legal certainty for individuals involved in the adoption of cultivation of culturally acceptable peyote on an economically viable commercial scale are summarized. The progress toward and impediments to legally protected cultivation of Lophophora williamsii, commonly known as peyote, are elucidated. Recent increases in the ceremonial and medicinal consumption of peyote are inferred from published data and personal observations of the authors. The conservation-based rationale for peyote cultivation is that the predictable shift in the primary mode of production from the current unsustainable harvesting of wild peyote in habitat to regulated cultivation of peyote, either in situ or under glass, would provide alternative supplies of peyote for current and future use by the Native American Church. Such a change in the principal peyote production system from wildharvesting to cultivation would logically reduce the harvesting pressure on the peyote populations that survive the intense overharvesting inherent in the present system. We summarize current and evolving aspects of the regulatory environment and emerging perceptions regarding the need for U.S. federal regulations that would provide legal certainty for individuals involved in the adoption of cultivation of culturally acceptable peyote on an economically viable commercial scale. Published on-line www.phytologia.org Phytologia 95(4): 314-320 (Nov. 1, 2013). ISSN 030319430