Cycad Tour of Mexico
Fascinating and entertaining article covering Ian's
recent horticultural tour of southern Mexico, mouth-watering fare
for Cycad lovers, and nice pics!
Ian Watt, Brooklands Plants, Dorchester, Dorset
[an error occurred while processing the directive]
Above: clockwise from top left: Dioon edule,
Dioon merolae, Yucca and Pico de Orizaba, Agave sp., Zamia furfuracea,
Jeff Chemnick with Ceratozania whitelockiana, D. merolae.
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 (see cover of "Chamaerops" # . 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.
We are planning a return trip in Nov 2001. If anyone
is interested in a similar tour scheduled for Nov 2001, please get
in touch with me via the EPS.
Readers Comments:
(No comments yet. Be the first to add a comment to
this article!)
|
 |
[an error occurred while processing the directive] |
