POSTCARD from Mexico N°13

(By Fernando Rivadavia, March 27th, 2004) 

P.emarginata at last!

                After a frustrated attempt to find P.emarginata on March 20^th, I returned to the Puebla/ Veracruz border on Saturday March 27^th for another try. I have to admit that my hopes were not very high, since during the week I had been unable to obtain any additional new location data that could be helpful. I was basically at the same spot I’d left off the week before. I did however have some extra help: my longtime CP friend from Ireland Joe Mullins and his friend Helen Butler who are here in Mexico on holliday. Maybe 3 pairs of eyes would be better to search for P.emarginata...  

                I had so little hope of finding P.emarginata that I didn’t even want to waste much time looking for it. I planned a “touristy” trip for the weekend, with a brief passage through P.emarginata area. On Saturday we left early in the morning for the ruins of El Tajín, near the town of Poza Rica in Veracruz state, ~300km away from Mexico City. This was a fantastic place, with several pyramids built by pre-Aztec cultures about 1000 years ago, located among rainforest-covered hills. We arrived around lunchtime, spent a few hours exploring the site, and then headed S to the Teziutlan/ Atzalan/ Tlapacoyan area.

                Driving from Tlapacoyan to Teziutlan there are numerous interesting ravines seen from the road, but none seemed too easy to reach. At about 1500m altitude, the road crosses a stream. I’d stopped here the week before, but had seen nothing interesting, there being no vertical walls or cliffs. But since it was at about the right altitude and the Cascada de Oligui was supposedly located along this road somewhere, I decided to give this stream a second try.

                Our first attempt to descend to the streamside was frustrated by a steep hillside with tall grass, loose dirt, and lots of garbage too. We climbed back up to the road and crossed to the other side of the stream. Pushing my way through the thick forest vegetation (with damned prickly vines!), I suddenly came upon what appeared to be an old trail. This was not so easy to follow since it was heavily overgrown. It went parallel to the stream for a short stretch and turned away from it, circling around a small hill.

                Suddenly the trail became a narrow pathway on a cliffside and I realized the stream plunged into the depths forming a waterfall. This was completely hidden from the road by the cloud forest, what a surprise! The trail led farther away from the stream and waterfall along the cliffside until it met a larger, clearer trail coming from above (which I later realized led back to the road). I followed this larger trail down the mountain until there was a fork. To the left it seemed to circle back around the mountain, parallel to the path I’d followed along the cliffside, only much further down. Maybe it circled back through the forest to the base of the waterfall.

                The fork to the right led straight down to another waterfall from a different stream. I could see rock walls next to these falls and decided to explore there first. But I found no Pings unfortunately. I climbed back up to the fork just in time to meet Joe and Helen coming down the trail. I’d last seen them back up at the road. You see, they are also biologists and were going much slower than I because of their awe with the exotic tropical vegetation. Just a reminder to me of how local flora and fauna is taken for granted by us who live in tropical countries....

                So I met them at the fork and suggested they push ahead along the unexplored trail to the left, while I cleaned my glasses. It didn’t take long to hear Joe shout out: Pinguicula emarginata!! Pinguicula emarginata all over the wall!! I rushed ahead and sure enough, there they were, almost just around the bend, only a few steps away from the fork. Like the description in an old issue of the IPSG, P.emarginata grew with mosses on sandstone cliffs partially shaded by the forest. Yet these were not facing North, but more like East or maybe NE. Curiously, there were moss-covered tree trunks right alongside the base of the cliffs, but not a single P.emarginata seemed to appreciate growing on these.  

                At first we did not see “thousands” of P.emarginata, as described in the IPSG, but moving a bit further along the trail we realized they actually did grow by the thousands, maybe more, completely covering the cliff from the base to as far as the eye could see above. And they were in full bloom too! Wow, what a spectacle it was to see so many P.emarginata flowers! Comparing to all other Ping sites I’d seen in Mexico, this was surely one of the most spectacular. It was probably the largest concentration of plants and flowers I’d seen so far, even more so than the P.esseriana/ ehlersiae/ jamauvensis site I saw a few weeks ago near Ciudad Victoria, Tamaulipas.

                Apparently we’d found the Cascada de Oligui site. Although there was no sign indicating a name for this waterfall, the location information was compatible, as was the altitude and the habitat description. When we arrived at this site it must’ve been around 4:30 or 5:00 in the afternoon, which meant the sun was already a bit low in the sky. Furthermore, it was a cloudy day – so we had some difficulty taking pictures of P.emarginata. We were either forced to use the camera’s flash, which left flowers a bit white-washed, or else we had to hold VERY still and take longer exposures, hoping the wind would not bounce the flowers around too much. And since the plants were growing on vertical walls, there was no chance of using a tripod either. So out of ~100 pictures taken, only around half turned out to be acceptable and were not deleted from my computer.

                As usual, I saw lots of variation in flower shape, size, and color. Petals were longer or shorter, wider or narrower, with the ends of the lobes rounder or more pointed. Some were beautifully colored in purple-pink with darker veins, while others were nearly white, with the veins resembling mere shadowed indentations in the petals. All had a yellow mark at the base of the lower lip, but this varied in size as well as intensity, from a bright greenish-yellow to an almost unnoticeable yellow-white patch.

                As for the leaf rosettes, most were colored in the usual Pinguicula-green, but there were also varying amounts of maroon-red, including plants that were entirely this color, sometimes the scapes being a nice red color too. I was surprised to find a few rosettes with succulent winter leaves, often reddish near the base. I had been under the impression that this species did not form winter leaves.

                Even more interesting than the discovery of winter rosettes was the observation of another phenomenon, a very clear adaptation of P.emarginata to vertical habitats. We realized that the inflorescences bearing open flowers pointed outwards from the cliff, while the scapes in fruit were bent backwards, pressed against the rocks. Obviously, it is more advantageous to initially have the flowers sticking out from the walls where pollinators can see them more easily. But if they remain in this position, most of the seeds would be lost as they fell to the forest floor below. Therefore, by positioning the scapes closer to the cliff face after pollinization, P.emarginata guarantees that a larger amount of seeds actually fall in a suitable habitat among the mosses on the vertical wall, and not in the leaf litter far below. I had already observed this same adaptation once before, back in 1996 or 1997 with P.ramosa in Japan, which also bends its scapes backwards towards the cliff. I wonder if any other Ping species do this too? In fact, I wonder what happens to the scapes of these 2 species in cultivation when they are growing in horizontal media, and not on cliffs? Do the scapes actually change position after pollinization? Can anybody give me a light here?

                So just to wrap things up, we were at the P.emarginata site almost until dark and only arrived back in Mexico City at 11pm, after having driven 750km. On Sunday we saw no Pings since we only did regular touristy stuff and didn’t go too far, driving only ~250km.