Lophophora diffusa

Name and species circumscription

The accepted name is Lophophora diffusa (Croizat) Bravo. The historical L. echinata var. diffusa and L. williamsii var. diffusa describe the same name based on one type. POWO also includes L. koehresii (formerly also L. diffusa var. koehresii) and L. viridescens here. Their features and origin may matter for specimen identification, but in the atlas they are linked to one account of the accepted species. [2-WWW]

POWO defines the range as Mexico from Querétaro to Hidalgo. The regional flora description and ecological studies discussed mainly concern plants from Querétaro. Results of experiments on these populations retain this geographical scope, even with a broader taxonomic treatment of synonyms. [2-WWW] [Arias and Aquino 2019, Flora del Bajío, p. 112–116]

Stem, areoles and underground part

In the regional description, the stem reaches 7 cm high and 12 cm wide. It is spherical or flattened, solitary or branched at the base. Its green surface has a yellowish tint. Rounded tubercles, 2–3 cm long and 1–2 cm wide at the base, form very low, wavy, spirally arranged ribs. The flora gives up to 13 ribs. Indistinct rib boundaries correspond to the gentle merging of adjacent tubercle bases. [Arias and Aquino 2019, p. 112–113]

Circular areoles are 0.9–2 cm apart and bear white, soft hairs called trichomes. Their dense layer shelters the stem tip. Adult plants lack spines. The thickened, napiform root and underground stem base make up a large part of the whole plant. The flora's description of this structure concerns the genus, while colour, ribs and dimensions refer to L. diffusa from the region covered by the account. [Arias and Aquino 2019, p. 112–114]

A pale flower and red fruit

Flowers arise from young areoles near the tip and remain partly immersed in the hair layer. In plants described from Querétaro, they are 2–2.5 cm long and 1.3–2.2 cm wide. Outer tepals are lanceolate, white with a green central stripe. Inner ones are narrower, white with a yellowish or pink tint. White stamen filaments surround a yellow style ending in a white stigma with 5–6 lobes. [Arias and Aquino 2019, p. 112–113]

The red, club-shaped fruit is 1.5–2 cm long. Seeds are black, around 1.5 mm long. The regional flora records flowering in March and April and from July to October. Fruits were mainly observed from May to September, with possible longer ripening. This calendar describes Mexican sites, while flowering dates in a collection depend on the plants' own growth cycle and conditions. [Arias and Aquino 2019, p. 113]

Pollination and seed formation

Controlled pollination indicates predominance of cross-pollination and partial self-incompatibility. Hand self-pollination was less effective, and isolated flowers without pollen transfer did not fruit. Adding pollen to flowers accessible to insects increased seed production. The result defines the reproductive system of the population studied. [Briseño-Sánchez et al. 2020, pp. 246, 248–249, 251–252]

In one Querétaro population, reproductive censuses were conducted in 2015–2021, beginning with 468 marked plants. Solitary bees of Macrotera, Lasioglossum and Ashmeadiella, and beetles of Acmaeodera touching anthers or stigmas, were observed. Visit rates in groups of flowers differed between seasons. In 2018, after five hours of isolation, nectar was detected in 78% of 70 flowers studied on 62 plants. Among flowers containing nectar, its mean volume was 0.054 ± 0.007 µl, with standard error. [Briseño-Sánchez et al. 2022, Materials and methods, Results, Fig. 1]

In 2021, around 23% of 113 flowers assessed on 92 plants had feeding damage. When the perianth, anthers and stigma were eaten, no fruits were recorded. Less extensive damage co-occurred with a small proportion of fruiting. The results link pollen availability, insect behaviour and floral-organ condition to seed formation. [Briseño-Sánchez et al. 2022, Table 2]

Seed persistence and early development

An experiment conducted in 2018 compared seeds collected in 2014 and 2018. They were stored in paper bags at 20 ± 2°C. 50 seeds from each batch were sown in ten dishes of five seeds, on 1% agar at 25°C with a twelve-hour photoperiod. Observed germination was 52% for the four-year-old batch and 62% for the batch from the experiment year. The final proportion germinating did not differ significantly in the authors' analysis. [Briseño-Sánchez et al. 2024, pp. 4–7]

At the end of the brief laboratory observation, seedling survival was 58 ± 4.81% for the older batch and 61 ± 5.92% for the younger, expressed as mean and standard error. The difference was not significant. Retention of germination ability for around four years was documented under these storage conditions. The hypothesis of a persistent soil seed bank requires field studies. The batches compared also differ in collection year, and experimental conditions describe a laboratory result. [Briseño-Sánchez et al. 2024, pp. 6–9]

Seven years of field censuses recorded 127 new seedlings, from one to 31 annually. The result shows renewal of a natural population with substantial variation between years. Successive stages, from pollen transfer to young-plant survival, are described in the article on pollination, seeds and seedlings. [Briseño-Sánchez et al. 2022, Table 1]

Habitat and distribution beneath shrubs

In central Querétaro, the species occurs in small-leaved dry scrub on flat or gently sloping ground. The flora gives sites between slabs of limestone-derived clay shale at elevations of 1200–1900 m. Shrub canopies divide this apparently uniform space into microhabitats with differing access to light. [Arias and Aquino 2019, p. 113–115]

A study published in 2026 surveyed 380 individuals on ten 49 m² plots. Beneath vegetation were 296 cacti, around 78%, although sheltered space occupied 57.5% of the study area. Distribution was clustered. Under Larrea tridentata, 153 individuals were recorded, compared with around 109 expected under a distribution proportional to canopy area. These are data from one population selected for its high local abundance. [Jiménez-Sierra et al. 2026, pp. 3–5, Tables 2 and 4]

Light and seasonal photosystem activity

The 2011–2012 study compared adult plants beneath Larrea tridentata and at open sites. The methods describe six cacti in each group, with stem diameters around 4.5 cm. Chlorophyll fluorescence was measured once in each of four seasons. Less photosynthetically active radiation reached beneath shrubs in spring, summer and autumn. In winter, the difference was not significant. Temperatures near the stem surface were lower under shelter in spring and autumn. [González-Salvatierra et al. 2024, pp. 2–4, fig. 2]

In spring, exposed cacti showed a strong decrease in Fv/Fm, the maximum photosystem II efficiency measured after dark adaptation. Values rose in summer and autumn, which the authors linked to reversible regulation of the photosynthetic apparatus. In winter, effective photosystem II yield and estimated electron transport fell in both microhabitats. Under short light pulses of increasing intensity, the response depended on season. Shrub shelter and plant age therefore define the context in which a light level becomes beneficial or stressful. [González-Salvatierra et al. 2024, p. 4–8, ryc. 3–5]

Light in a collection

When choosing a position, field data support considering season and stem temperature together with light quantity. Adult plants can function at open sites, but in spring the studied population showed its greatest Fv/Fm decrease there. Bright shelter reducing peak radiation corresponds to the conditions of one microhabitat studied. In the cooler part of the year, photosystem responses also changed in shaded specimens. These findings inform exposure choices, without a shading percentage for pots or greenhouses established in these experiments. [González-Salvatierra et al. 2024, p. 2–8]

Genom chloroplastowy

A chloroplast genome of 115 689 base pairs was read from a specimen maintained in a laboratory. Two inverted repeats each contained 1688 base pairs, and annotation distinguished 100 unique genes. The sequence came from a plant intercepted in a shipment by customs, with an unknown natural population of origin. It is reference material for organelle DNA comparisons and variation between specimens. [Zhang et al. 2026]

Zmiany siedliska

The regional flora describes plant loss through direct specimen collection and conversion of sites into farmland, pasture and roads. The association of much of the population with shrubs means preserving cactus stems alone does not recreate the entire habitat system. Neighbouring plant canopies and the distribution of sheltered places where further plants develop also matter. [Arias and Aquino 2019, Flora del Bajío, p. 113; Horticulturae, p. 4–8] [Jiménez-Sierra et al. 2026, Flora del Bajío, p. 113; Horticulturae, p. 4–8]

Related articles