News views information and photos of Cycads
Samples from the Herbarium at Kew on Encephalartos Macrozamia and Dioon
Cycad tour of Mexico 2000 by Ian Watt
The ten day cycad tour of Mexico was organized by Californian Jeff Chemnick, who has over twenty years of experience observing Mexican cycads in habitat. I met Jeff and the other three members of the group on the 29th of February in Veracruz . The aim was to observe fifteen species of cycad in habitat; to make comparisons between related species; and to look closely at habitats, aspects, populations, and recruitment. We were to head north along the coast, then inland through the mountains towards the Pacific, south into tropical forest, and then back towards Veracruz, thus completing the circle.
Transport was by air conditioned minibus. Accommodation was in modest hotels along the route. The distances between locations was sometimes great, and a good pace had to be maintained in order to cover the itinerary.
A few miles drive up the coast from Veracruz followed by a two mile hike along the seashore and through the high dunes got us to our first and possibly most unusual cycad locality: Dioon edule, growing in sand and soft sandstone about a third of a mile from the shore. The Dioons had multiple trunks over a meter in length with a head of thirty or more leaves. Many were male with immature cones and some plants covered an area of five by five meters. The total area of cycads was less than one hectare grouped near the ridge. All were facing towards the sea and surrounded by thorn brush, Bursera, and an Acrocomia. The plants generally appeared to be in good health, considering the harsh location and poor soil, with the exception of one with leaf damage from insect activity. A couple of seedlings were found at the bottom of the slope.
We drove inland, stopping briefly at a site where Zamia loddigesii was once very common, before heading into the hills and the Palma Sola region. Sabal and Tabebuia trees were flowering in the lowlands alongside the fields of sugar cane, whilst higher up in the cooler air, oaks and pine dominated the countryside. Dioon edule was once abundant along the road out of Palma Sola, but with easy access and a demand from across the border, the plants were quickly depleted. The City's laws have helped curb the flow but have not stopped it. The few cycads we saw were growing along a dry and rocky stream bed surrounded by oak and grasses. Their trunks measured up to 1.5m and were charred black from clearing fires. Some had been cut down, and these were pushing out new growth from the base. No seed, seedlings or young plants were seen.
Further west, on a road cutting, a Ceratozamia had colonized the rock face. Known in the trade as Ceratozamia "Palma Sola," they are characterized by large, stiff, upright leaves with prominent spines. Seedling and mature plants were growing in fairly good numbers.
From the Palma Sola region we climbed to 1600m through steep valleys and round sheer rock outcrops clothed in pine and oak to see a relatively new discovery. Ceratozamia morettii is a medium sized cycad with leaves to 1.5m and grows in the cloud forest of the Sierre Madre facing the gulf. Described in 1998 with a population estimated at 300, this is a cycad that is difficult to observe. Its preferred habitat is sheer rocky walls with drops of 150m to the valley floor below. Average rainfall in this region is 2m. Ceratozamia morettii is high on the want lists of collectors; therefore, the location has not been published. Other plants growing in the vicinity were Gunnera, Alnus, Clethra, Dendropanax, Ilex discolor, Liquidamber, Magnolia, Quercus laurina, xalapennsis and germana.
The drive to the next locality was through more spectacular scenery, including views of Pico de Orizaba, otherwise known as Citlailepetl. At 5610m above sea level, it is the highest peak in Mexico and third highest in North America. The last eruption was in 1566. Ceratozamia mexicana is an elegant, narrow leafed cycad. The location, El Esquilon, was a very steep wooded hill with Chamaedorea palms growing in the dense shade. The Ceratozamia were difficult to locate but a few were eventually found. A landslip had occurred recently and two large plants were found at the bottom of the slope. These were collected and later dropped off at the research institute.
The next stop was the Jardin Botanico and Institute of ecology in Xalapa, which provided an excellent opportunity to observe nearly all the Mexican cycads, some currently under investigation. We had a tour of the greenhouses and met Andrew Vovides, curator of research at the institute. Vovides, in conjunction with the local farmers, is involved in the development of cycad nurseries growing thousands of Dioon edule to generate income and reduce the threat on wild populations. The project was started about ten years ago near Chavarillo, the type locality for Dioon edule.
Along the Rio Pescardo we stopped to view Dioon edule clinging on the north-facing cliff walls 50m above the road. With trunks up to 3m, it is estimated these slow growing cycads are at least 500 years old and may be 2 or 3 times that. The cycads were hanging on to the rock face in a very precarious manner. Views to the river and valley plain some 200m below were breathtaking. From the Rio Pescardo we headed south through the Tillandsia trail, made famous by the pre-CITES Tillandsia and Orchid collectors.
Another hour or so later we were at El Mirador looking for a variety of Ceratozamia mexicana. The El Mirador cycad differs by having much longer, arching leaves with broader leaflets, and very reduced spines on the petiole. Also, the cones are much longer. Someday it may be separated out as a subspecies. We found two beautiful examples growing on a ranch: a mature male with cone, growing at the top of a bank, and the second on a high shelf in the owner's kitchen. It was a magnificent specimen with long trailing leaves. The owner of the ranch was very hospitable, handing out beers and showing us around his house and garden with great pride.
The next day we continued south on the auto route past Tehuacan in Peubla and towards the high desert. Pine and oak gradually gave way to the xerophytes, initially through large stands of Yucca elephantipes, densely branched and up to 10m in height, and then through huge numbers of the cactus Pachycereus weberi, and massive trees with stout trunks and dense crowns. Further along, the dominant plant was Neobuxbaumia, a tall columnar cacti. Huge barrel cactus, Dasylirion lucidum, serratifolium, and two species of Agave were recorded, as well as numerous other Cactaceae. The unusual and rare Fouquieria purpusii was only in one location, 4m in height and growing on a large rock. In the distance, growing at the foot of a cliff, was a large number of Brahea, which were the only palms in the area.
We left the high desert and drove into the hills towards Teotitlan Del Camino in Puebla. Dioon califanoi grows above the town of Teotitlan, at an elevation of 2000m. The road cuts through the colony with plants above and below in a narrow band. Many cycads must have been destroyed during its construction. Large areas of the hillsides in this region have been cleared for farming, and land too steep or rocky has sparse vegetation of thorn and oak. The cycads in this locality numbered fewer than 100, male and female, with semi mature cones and trunks up to 3m. There were few seedlings and no young plants. Dioon califanoi is easily distinguished from other Dioon by its strongly keeled leaf. There is one other known locality for Dioon califanoi.
On day four we headed for the Dioon purpusii locality Canada De Cuicatalan in Oaxaca, along 6km of powder dry track lined with thousands of Neobuxbaumia. This cycad grows in similar habitat to califanoi, scattered along a band of mountain side at 1500m, with the road cutting through the colony. The hillside was more densely covered in thorn and it was necessary to track along narrow goat paths to get to the plants. It's a large cycad, some with trunks of at least 4m. Other plants in the area included impressive stands of Brahea dulcis, Nolina longifolia, Dasylirion serratifolium and Agave potatorum. The numbers of Dioon were low with very few seedlings and no young or immature plants. There are seven known localities of Dioon purpusii.
We continued south, spending the night in the capital Oaxaca, and then moving onto a truly spectacular cycad locality. Cerro Gavilan is a rock outcrop standing 220m above the surrounding countryside, near the town of El Camaron. The cycads, Dioon merolae "El Camaron", only grow on the lip of the North-West face at an elevation of 1500m. The climb was through oak and pine forest with large boulders and deep leaf litter. The top of the rock was sparsely covered with Nolina and Agave. The Dioon had trunks up to 4m
upright and more prostrate, with some hanging down over the edge. There were less than 30 cycads in all, male and female, but again no young plants and only one seedling located at the base of the rock. Dioon merolae populations are widespread with seven known localities. They can be identified by their flat fronds with crowded leaflets.
A four hour drive followed to our hotel in Zanatepec on the Pan American highway, a very busy area with numerous military stops. Our next cycad locality, El Rancho, was a short drive away just over the border in Chiapas.. Two giant Dioon merolae were growing in thin pine forest 30km from the Pacific coast and at an elevation of 830m. The two cycads, a male and a slightly larger female, had numerous trunks emerging from the base, prostrate and upright measuring up to 5m in length. The base of each plant was charred from fires and a piece of broken trunk lay on the grass nearby. They were growing just below the top of the slope facing in a northerly direction. Several smaller, mature plants were growing in the gully at the bottom of the slope 15 meters away. There were seedlings on the slope but no young plants.
Moving east and further inland into dense tropical forest habitat of Zamia splendens, we encountered strange lizards, colorful birds and carpets of Chamaedorea in the forest. Zamia splendens is a small cycad with a subterranean stem and two to four leaves. We searched a part of the forest where they had been previously seen; unfortunately, it proved too elusive for us to find. Ceratozamia miqueliana was found further up the valley at Lago Mal Paso, growing in cooler conditions at a higher elevation. This is a small to medium sized cycad with an erect crown of leaves to 1.8m. This locality was on the edge of a remote but expanding village and is under threat. We found three large plants cut down in an area cleared for coffee. Three more plants were located on a steep slope at the edge of the forest.
Our overnight stop was in Tuxtla Gutierrez, not far from the Sumidero Canyon, one of the most spectacular geological faults in America. Vertical walls plunge a staggering 1300m to the bottom of the gorge and the Grijalva river. Ceratozamia robusta grows on the sides of the canyon in low numbers, and a nearby nursery was selling robusta plants for a few pence each.. We then drove north-east through forests of Pinus montezuma, stands of Brahea dulcis, and a village with numerous Ensete ventricosum. We spent the night at the Aqua Azul falls, a complex of rapids, cascades, and brilliant turquoise pools, surrounded by tropical vegetation, before heading north to Palenque.
Zamia lacandona grows on the steep slopes behind the Maya ruins in the Lacandona forest at Palenque. Only one was seen high up on the trail: a small cycad with erect arching leaves up to 1.5 meters long. On the road-side north of Palenque, Zamia loddigesii was growing amongst tall grass. Easy to spot during the dry season, Zamia loddigesii is a small cycad with a subterranean stem with one to six leaves on a mature plant. Young plants and seedlings were also present.
From Palenque we had a long fast drive to Acayucan in Veracruz for an overnight stop before continuing on to the next locality east of Tuxtepec, Oaxaca, on the Palmares road. Dioon spinulosum occurs at elevations of 100m to 150m in Veracruz and Oaxaca, preferring a warmer and more humid climate than some of its relations. The cycads were on steep limestone islands surrounded by farmland with many more growing on the distant hillside.. Two sites were visited. The first was a bare rock cleared of almost any other vegetation possibly by fire. The cycads were in full sun on the top of the rock, the crowns holding only one flush of leaves. The second site was heavily forested and larger in area. The ground was very rocky and steep, with little soil. The Dioon here were up to 10 meters in height and one of the dominant plants in this locality. They held two to three flushes of leaves and some had immature cones. Seedlings were in abundance, but there were no young plants. Bats were roosting under the leaves of one plant. Also growing among the Dioons are giant Dioscorea macrostachys, which look like turtles with vines growing out the top.
From Dioon spinulosum in the morning it was a short drive to San Bartolome Ayautla, the type locality for Dioon rzedowskii in the afternoon. Described in 1980 and endemic to Oaxaca, this Dioon is a large cycad with a trunk up to 5m. The locality was near the town of Jalapa at an elevation of 430m. Permission from the villagers was necessary and a guide accompanied us 200m down the steep canyon. On the way down, plots of land less than a few meters across were being farmed. The Dioons were growing in a spectacular setting in huge numbers, clinging to steep outcrops of limestone, some upright with others draped down over the rocks. Orchids and Agave were also in abundance. The river was another 150m below and disappeared through a maze of wooded canyons. This is one of the most impressive populations of Dioon and appears to be under no immediate threat. Further up the canyon at a much cooler elevation of 770m, was Ceratozamia robusta. These cycads were growing under a canopy of oak. Only a few plants remain amongst the boulders surrounded by farmland. The largest had an trunk of 0.5m and 20 leaves 2m in length.
On the last day and still in the state of Oaxaca, we drove to see a recently described and named cycad by Jeff Chemnick, Ceratozamia whitelockiana.. It is closely related to Ceratozamia miqueliana, but with some notable differences, namely smaller cones, longer petioles and blue-gray new leaves. The locality was a steep, wooded slope 70km south of Tuxtepec at an elevation of 550m. This was not the type locality and only one plant was observed.
We took the coast road on the way back to Veracruz to look at Zamia furfuracea. The locality for this cycad was 50km southeast of Veracruz on coastal sand dunes. Once widespread and common in this area, it is now quite scarce. Vegetation on the dunes was sparse with thorn scrub, coarse grasses, and stands of Sabal mexicana. Walking through the dunes for a mile, we located less than 20 cycads, all small with five or six leaves up to 50cm long, some with new leaves emerging. Cows and goats graze the dunes but the main reason for this cycad's scarcity is over collection.
Any problems encountered during the tour were relatively minor. Despite precautions, all members of the group with the exception of Jeff suffered gastrointestinal discomfort to varying degrees which in most cases lasted a couple of days. The mains water is of questionable quality and even taking a shower is risky. March is in the dry season so mosquitoes were only present in low numbers; however, ticks and sandflies were a nuisance. Some hikes were over rough and very steep terrain, often in the heat of the day, and a certain level of fitness was essential. Military road blocks were numerous, but the delays were short. The police stopped us on a dirt road in a very remote area where they held us for quarter of an hour before eventually letting us proceed. None of the officials spoke English. Generally the locals were helpful and friendly. There are areas where Jeff will not venture despite the call of new cycad localities, as outlaws and drug dealers make it too risky. It is also worth mentioning that some of the localities were potentially dangerous and great care had to be taken, especially when looking at the cycads on cliff edges and rock faces. Many of the cycad localities are in remote areas that would take years to find without a guide. Jeff Chemnick is one of only a handful of people that know these localities.
The cycads are truly remarkable plants and to see them in the wild is a real privilege. Most memorable were the large Dioon growing on cliff tops and the giant Dioon merolae in the pine forest. The Ceratozamia also made a big impression, being highly ornamental with elegantly arching leaves and glossy leaflets. I've not seen any in cultivation come close to these.. It was interesting to note how some species of cycad grow at fairly narrow elevations, and by following the contours through the canyons, Jeff has located new cycad populations.
The cliff top habitats presented intriguing questions as to why the cycads are found just on the ledges, usually with a northerly aspect. Possible reasons could be competition from other plants, climate fluctuations, and human interference. More could be learned of these plants if their age could be accurately determined; unfortunately, up to now there is no scientific method of doing this.
Habitat destruction and poaching are the greatest threats to cycad populations, and although no species has become extinct in recent history, the threat is very real. Generally Dioon suffer from poaching and Ceratozamia and Zamia from habitat destruction. What is also disturbing is the lack of recruitment in some populations. This presents no immediate threat as cycads are such long lived plants; however, it would have been encouraging to have seen some immature plants.
The tour was a resounding success. We saw sixteen species of cycad at over twenty localities and covered nearly 2000 miles without serious incident or injury, traveling through parts of Mexico seldom seen by Europeans. One item desperately needed was a field guide to the plants of Mexico, as on many occasions we were at a loss to put a name to a plant. From the remote mountain villages to the busy cities, Mexico is a country of many contrasts and a delight to tour. The sheer variety of plant habitat is overwhelming, making Mexico a botanist's paradise.
Thanks to the RHS Bursaries committee for part sponsorship of this trip.