A 5600 Kms TOUR IN MEXICO

 

(By Oliver Gluch, August/September 2009

 

Part 3 : In San Luis Potosi to the Arroyo Tolimán Canyon

After having passed the night in Cerritos, San Luis Potosí (there was no hotel available earlier on the way), we turned back south towards Villa Juarez and turned southwest towards Puerta del Rio. The area was really dry (Yoshua trees dominating the landscape) and we have passed already several places where gypsum outcrops occured. After having passed the little village Buenavista, we were stopping at a gypsum hill, where Fernando Rivadavia has found P. gypsicola during one of his tours. The site was bone dry and I had not much hope finding plants in flower. The vegetation was a xerophytic shrub vegetation with Puya sp., Agave and cacti. Nevetheless we found Selaginella sp., a good sign also for finding Pinguicula. Walking up the hill on the north-western slope (always paying attention to all the plants with stings and thornes along the way and the knife sharp surface of the gypsum rocks), we soon have found the first Pinguicula gypsicola, and what surprise, they were just beginning to flower! The summer leaves were also just emerging, most of the plants were growing along with Selaginella (often still dormant) in slightly eroded gypsum soil or even directly on the crystalline gypsum. P. agnata site was already pretty dry, but the site of P. gypsicola was even drier. Where was the humidity coming from? As we went there in the morning, no sign of fog was visible and temperatures were around 28-30°C. The plants somehow must use the water from the winter leaves. I really have to think of changing my cultivation method for this species. Flowers were not very variable neither in colour nor in shape, but it was impressing how the plants could grow on bare rock under such dry and hot conditions. With these dry conditions it was impossible to see P. takakii, the annual species Fernando found in a later time of the year also on these gypsum hills.

P. gypsicola gyspum hill in Buenavista.

 

Photo : O. Gluch

 

A Cactus in Pinguicula gypsicola site.

 

 

Photo : O. Gluch

 

Pinguicula gypsicola with Hetchia.

 

 

Photo : O. Gluch

Plants of Pinguicula gypsicola with Selaginella.

 

 

Photo : O. Gluch

 

We moved on on the white dirt road (due to the gypsum we left a white dust cloud behind our van, not a pleasure for the following cars behind us), passed some gypsum quarries (one of them must have been Minas San Raffael, the type location for P. gypsicola, but there was no sign indicating the mines' names) and then climbed up a hillside, before getting into another valley. Also on this side of the hills we found P. gypsicola along the road at several places, sometimes growing on vertical gypsum rocks (really nice!).

P. gypsicola growing on vertical gypsum rocks.

 

Photo : O. Gluch

 

Pinguicula gypsicola, summer rosettes.

 

 

Photo : O. Gluch

 

There Hans was looking for the site he has been 20 years ago, which he named "Santa Gertrudis", after a village that was next along the road (I haven't found it neither on Google Earth nor on my Mexico maps). The place was much more densely covered with stingy shrubs, so climbing up the hill was much more difficult. But we had not to climb to far before we found again P. gypsicola. Also at this site some plants were in flower and only a few plants had some immature seed pods, indicating that flowering season was just starting. But at this site, there was also another Pinguicula growing.

Pinguicula gypsicola flowers.

 

 

Photo : O. Gluch

 

In more shady places under trees or shrubs, in dry moss, we found summer rosettes of Pinguicula ehlersiae. If you grow a clone of P. ehlersiae named "Santa Gertrudis", it is coming from this place. Also at this location you are wondering how the plants get enough moisture to produce even summer leaves, but there must be some source of moisture.

 

The habitat of Pinguicula Ehlersiae from Santa Gertrudis.

 

Photo : O. Gluch

Pinguicula Ehlersiae from Santa Gertrudis growing in dry moss.

 

Photo : O. Gluch

We continued the dirt road and turned south to get back again on highway 70, leading to the city of San Luis Potosi. Along the highway there is the only known place for P. potosiensis (for all who don't believe in that species, a P. moranensis clone).

A nice butterfly at Pinguicula potosiensis site.

 

 

Photo : O. Gluch

We stopped at a site where Hans found some P. macrophylla as well 20 years ago, but we were not lucky to find the plants again (unfortunately at that time GPS devices were not very common to get more exact location data), but Kamil and Radek found further up in the pine-oak tree forest some "P. potosiensis", but not in flower. Along the road there was also a village named "Santa Catarina", another location of P. ehlersiae, but we had no time to make an excessive search for these plants, as they were anyway not in flower during that time of the year and we had already seen this species earlier the day. In addition we had quite a long trip in front of us, as the next location should be the Arroyo Tolimán Canyon close to Zimapán at the border of the 2 states Hidalgo and Querétaro, the type location for Pinguicula agnata and also habitat of Pinguicula elizabethiae. Would it be as dry there as in San Luis Potosi and would the plants be in flower?

More about it in my next postcard."

Oliver