I began to search for the answer to this question in the books by well-known and experienced cactus specialists. But very soon I realized that I didn’t have even basic knowledge that could help me understand and follow valuable pieces of advice and instructions of venerable authors. And it is evident that knowing so little about the subject matter it is extremely difficult to write a good guide for cactus beginners.
For example, one book said that epiphytic cacti (growing on trees) couldn’t bear lower temperature and overdry conditions. But I had several Selenicereus cactuses, that were typical epiphytes, which could stand cold and dry wintering without much trouble. Why? I did not understand.
Another book advised not to subject cacti “originating from tropical forests of Brazil” to difficulties of severe wintering. I had some cactuses which native land was Brazil, but I did not know whether they were tropical or not.
The third author warned against overdrying of “tillered wood cactuses”, but some pages on he advised to keep Chamaecereus “as chilly as possible” during wintering. But as far as I know this type of cactus is both wood and tillered! Where should I search for the keys to all these riddles?
The first gleams of understanding came unexpectedly. Some friends of mine gave me several photos of cactuses that they had by chance and didn’t need anymore. Somebody of them advised me for fun to arrange a photo album of “thorny friends”, and this idea turned to be very fruitful. I picked more and more photos, but I pasted them not in the album, but on separate sheets of dense paper where I could also write down everything, that I learned about this or that cactus: the name, the description, data on culture and, of course, the native land.
And when I collected several hundreds of these cards, I often went through them and it served me right: soon I could those cacti? which suffered from dry cold. Some names were similar, some were different, but the outward similarity of certain cactus species was evident. Yes, they all were epiphytes and they all tillered. The majority of them really originated from Brazil, though for the some of them the native land was Jamaica, West Indies and even Mexico.
But the most surprising fact was that despite different names and places of origin all these tillered epiphytes had one common feature – they all had bare stalks. Their bright green thin skin was not protected by neither hairs, nor thorns, nor grey wax film. Only several tiny and thin seti. They all looked rather defenseless in comparison with other cactus species.
And this very defenselessness turned out to be the key to the riddle that I could not solve. I understood why this feature was developed – because of tropical forest conditions.