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Re: What would you like to know about Melocactus?

Posted: Tue Oct 23, 2007 5:01 pm
by Vic
Amazing pic Marlon! To be honest I never even thought of hummingbirds as being the pollinators of Melocacti, I know they have fairly small narrow flowers which generally barely emerge from the cephalium but always presumed insects of some description as being the pollinators.

Re: What would you like to know about Melocactus?

Posted: Tue Oct 23, 2007 5:38 pm
by Marlon Machado
Hi Maria,

The plant is not buried, Melocactus paucispinus is disk-shaped, it grows larger than tall.

Vic,

Yep, they are pollinated by hummingbirds - the flowers seems to be small because they are buried in the cephalium, usually only the petals showing above it. But the flowers have long tubes, and thus the right shape for the hummingbirds. And the flowers are also of the right colour - hummingbirds are attracted to red, magenta and pink colours.

Ian,

This is another Melocactus that is not looking so nice - the plant was photographed in the dry season, and it was quite shrunken and dehydrated, and it also has a yellowish color, evidence of sun-stress.

Cheers,

Re: What would you like to know about Melocactus?

Posted: Tue Oct 23, 2007 5:51 pm
by Maria J
Oh right! Thanks Marlon!

Re: What would you like to know about Melocactus?

Posted: Thu Oct 25, 2007 12:31 pm
by Stuart Estell
One thing that puzzles me is the evolutionary route the various cephalium-bearing genera have taken - both the columnar ones and Melos/Discos. What is the purpose of them, and/or how did they come about, do we know?

Re: What would you like to know about Melocactus?

Posted: Thu Oct 25, 2007 12:33 pm
by North Lincs Mike
Hi again Marlon.

Another question - is it possible to get seed of any of the multi-ceph species from anywhere?

Mike

Re: What would you like to know about Melocactus?

Posted: Fri Oct 26, 2007 5:33 pm
by Marlon Machado
Hello Stuart,

I started a new thread about the cephalium in cacti to answer your question.

[hr]
Mike,

I do not know where you can find seeds of the "multicephalus" form of Melocactus ernestii. A few years ago, when plants could still be found at the place where this form grows, I visited the place with a friend of mine from France who specializes in growing Melocactus, Gerard Delanoy, and he collected seeds of this plant - his field number is GD 86.2. He probably has seedlings of this form, you should contact him and ask if he has any to sell. His website is http://www.melocactus.net/ and his email is delanoy@unice.fr.

Another friend who visited the same habitat with me and collected some seed was Graham Charles. His field number for this form is GC 491.03. He may also have seedlings of this species.

Cheers,

Re: What would you like to know about Melocactus?

Posted: Sun Oct 28, 2007 4:24 pm
by Marlon Machado
A friend of mine recently sent me the pictures below. This is a sad sight which unfortunatelly is still commonly seen in the roadsides of many areas in Eastern Brazil:
[img]http://i213.photobucket.com/albums/cc42 ... ale_01.jpg[/img]
Photo: Domingos Cardoso.
[img]http://i213.photobucket.com/albums/cc42 ... ale_02.jpg[/img]
Photo: Domingos Cardoso.
[img]http://i213.photobucket.com/albums/cc42 ... ale_03.jpg[/img]
Photo: Domingos Cardoso.
[img]http://i213.photobucket.com/albums/cc42 ... ale_04.jpg[/img]
Photo: Domingos Cardoso.
[img]http://i213.photobucket.com/albums/cc42 ... ale_05.jpg[/img]
Photo: Domingos Cardoso.
[img]http://i213.photobucket.com/albums/cc42 ... ale_06.jpg[/img]
Photo: Domingos Cardoso.
The cacti species in the pictures above are Melocactus salvadorensis (the more globular Melos, with shorter spines and shorter cephalia), Melocactus ernestii (the more elongated Melos, with long spines and tall cephalia), Pilosocereus gounellei, Pilosocereus catingicola, Arrojadoa penicillata, Stephanocereus leucostele, Tacinga palmadora and Tacinga inamoena.

It is common to see dozens of mature specimens of Melocactus with well-developed cephalia being offered for sale as ornamental plants along the main highways that cross the regions where these plants grow. The plants are collected in the surrounding countryside by the poor local people, and exposed at the roadsides for sale as ornamentals.

The local people are not to be blamed; actually, I pity them, because I know how difficult the situation is in these poor areas of the countryside, and the local people are only trying to supplement their sparse income by exploiting the natural resources available in their environment.

However, the collection of mature Melocactus specimens is highly detrimental to the natural populations of the Melocactus species. Melocacti only begin to reproduce when they reach a certain size, a process that in the case of the larger bodied species can take more than a decade. Only at maturity the cephalium develops, from which the flowers and subsequently the fruits are produced. Since Melocactus does not offset unless damaged at the apex, the propagation of new plants relies entirely on reproduction by seeds. Continuous collection of adult specimens can therefore wipe out entire populations: if every year all cephalium-bearing plants are removed from a population, there will be no production of seeds to replenish the population seed-bank, and each time fewer and fewer seedlings will be generated to replace the adult plants that are being taken. Thus, the repeated collection of cephalium-bearing plants will ultimately result in the complete demise of the natural populations.

I am very worried to see that now the stands of Melocactus being offered for sale by the roadsides is composed of mostly Melocactus ernestii plants. A few years back the most commonly species seen for sale was Melocactus salvadorensis, what makes sense because this is a species that grows in soil between shrubs in the region, thus in more easily acessible areas what facilitates the collection of plants. On the other hand, Melocactus ernestii grows only on rock outcrops, which are very big and steep in this region, and thus the plants of this species are less easily accessible for collection. The fact that now Melocactus ernestii is more common in the stands of plants for sale than Melocactus salvadorensis means that the last species has become rarer, what forced the collectors to start collecting Melocactus ernestii in the rock outcrops.

Melocactus salvadorensis is quickly becoming an endangered species in the region.

Cheers,

Re: What would you like to know about Melocactus?

Posted: Sun Oct 28, 2007 4:55 pm
by Cactus Jack
Wow at that rate it wouldn't be long before an area was totally wiped out :frown:

Re: What would you like to know about Melocactus?

Posted: Sun Oct 28, 2007 6:31 pm
by Vic
Hi Marlon,

Extremely sad to see indeed! Some of the plants look many many years old and as Stephen says it can't be long until they could even become extinct in certain areas, the fact that the local people are now collecting harder to reach plants is more worrying. I expect they only sell them for meagre amounts and only to exist - feed their children etc. Does ernestii grow in many locations or only few?

I wonder what can be done if anything to put a stop to it? If there is a market for such plants and people willing to buy them then it's going to be impossible I would imagine.

I saw a similar thing whilst in Big Bend with many Ariocarpus fissuratus being sold at the roadside for $5 each, you could tell they had been dug up many were badly potted with their huge tuberous roots bulging out of the top of the pots. Only difference being this is being done out of greed rather than seen as a way of making money to survive.

Re: What would you like to know about Melocactus?

Posted: Sun Oct 28, 2007 11:29 pm
by Greenlarry
Hi Marlon,i didn't realise there were so many species,mind they do look very similar(they always remind me of young Saguaro when not of flowering age)
One thing of interest I once read in an old cactus book of mine regards the naming of cacti way back in the early days. At the time a cactus was found and it was given the genus name Cactus, I forget the species name. But the interesting thing is that later it was renamed Melocactus and so it seems that the first cactus that was found all those years ago could have been a Melo!
I've fancied having a go with one of these but its rather off putting knowing that they need winter heat to survive. I don't have a greenhouse yet but even when I do it won't be heated enough for certain cacti,Melos numbering amongst them. Now a could of questions. How old do they need to be before forming the distinctive cephalium and are Discocactus closely related to them?