Cactus Explorers Journal - The Cactus Explorers Club

The Cactus Explorer ISSN 2048-0482 Number 4 May 2012
Fig.5 Acanthocereus tetragonus at
San Crisanto
Fig.6 Acanthocereus tetragonus at
San Crisanto
beach side we could see an Agave growing in
sandy ground. Both cerei were growing
entangled in bushes, especially the
Selenicereus. Only one Selenicereus was
growing on a dead stem of an Agave and
branches of this plant had a reddish colour,
unlike the dark-green colour of stems of plants
growing shaded by the bushes. The number of
ribs of Acanthocereus tetragonus varied between
three and five, but I saw one plant where a
new shoot growing from the base of a dying
stem had more than ten ribs. We had seen the
same (or similar) Acanthocereus species at
Uxmal.
The Agave was later identified by Ms. Ivana
Richter, the author of a 2011 book on agaves
published in Italian and German by the Italian
society AIAS, as Agave vivipara. There was also
a plant which resembled very much a South
African Cotyledon with less succulent
leaves(Fig.9). I have not been able to identify
that one.
Yucatán is also a major area for growing
Agave for fibre. I was surprised to learn later
that the plants grown for the sisal fibre are not
Agave sisalana as the name would suggest but -
A. fourcroydes, a sterile hybrid long called
henequén by the Mexicans. It differs from A.
sisalana by having slender, dark teeth spaced
widely along the margin of the leaf. A. sisalana
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Fig.7 Acanthocereus tetragonus at
San Crisanto showing 2 growth forms
has no teeth, or very minute ones. I suppose
many of the plants and inflorescences we saw
driving around Progreso belonged to these
two Agaves. After all, Sisal, once an important
port, lies only some 20 kilometres west of
Progreso. Another plant we saw a number of
times along the way was Opuntia dillenii with
large pads, yellow flowers and huge (up to 10
cm long and 6 cm wide) dark violet fruits.
Having returned to Merida we made another
attempt to find Mammillaria yucatanensis by
driving east towards the Rio Celestún reserve
on the western coast of the Yucatán penninsula.
The reserve covers the estuary of Rio Celestún
and protects mangrove vegetation as well as
large flocks of flamingos, pelicans and many
other birds. On the way to Rio Celestún and
back we were driving through a dry (semideciduous?)
forest of thin trees and tall bushes
but during several stops we found neither the
Mammillaria nor any other species of cacti.
A few years after the trip I purchased ‘The
Cactaceae’ by Britton and Rose, a book I did
not have access to when preparing for the trip.
There I read the original description of M.
yucatanensis with the location given at
Progreso and the note: "He (Dr. Gaumer) says
that the plant is rare on the land side of the
coastal marches". It is interesting that this vital
information which appears just two lines