What would you like to know about Melocactus?

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Marlon Machado
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Re: What would you like to know about Melocactus?

Post by Marlon Machado » Fri Oct 19, 2007 1:23 pm

Hello Stuart,

Salt-tolerant plants do not necessarily need salt to survive, as opposed to halophytes which are plants that need a salty environment to carry out its normal physiological functions. Melocactus violaceus for sure receives a salt spray from the sea, but the salt is washed away when it rains, at which time the sandy soil is salt-free at least close to the surface of the soil, where the roots of the Melocactus are located - roots of Melocactus are quite superficial and do not penetrate more than a few centimeters in the soil. Thus, when it rains M. violaceus is capable of absorbing salt-free water for its needs. Thus it is not a true halophyte - it does not need a salty environment to grow, although it can survive in one.

Cheers,
Marlon Machado.

Institute for Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
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anders
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Re: What would you like to know about Melocactus?

Post by anders » Fri Oct 19, 2007 3:43 pm

I would like to know what M. disciformis is. I have encountered this name many times on the Internet, but never in NCL and similar publications.
Marlon Machado
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Re: What would you like to know about Melocactus?

Post by Marlon Machado » Fri Oct 19, 2007 4:07 pm

Hi Anders,

The name Melocactus disciformis is a nomen nudum - it has not been published, and therefore is not valid. The plants that you usually find under this name are in fact Melocactus conoideus.

However, the name disciformis was used by Rizzini as a variety of Melocactus margaritaceus Rizzini, but the name disciformis as a variety is also an invalid name according the article 43.1 of the international code of botanical nomenclature (ICBN), because the species under which the variety was described, Melocactus margaritaceus, was not validly described according the article 37.1 of the ICBN - Rizzini failed to indicate a type specimen for the species. Thus, both Melocactus margaritaceus and Melocactus margaritaceus var. disciformis are invalid names. Both names were described by Rizzini in the same publication (Rizzini, C.T. 1982. Melocactus no Brasil. 142p. IBDF, Jardim Bot?nico do Rio de Janeiro.).

The name margaritaceus was later used by Nigel Taylor as a subspecies of Melocactus violaceus, and since Taylor indicated a type-specimen and Rizinni's description of Melocactus margaritaceus, it was in accord with the rules of the ICBN, and the name margaritaceus is therefore valid as a subspecies of Melocactus violaceus.

Back to the name Melocactus disciformis, it follows that it could also be used for Melocactus violaceus, but as far as I know the plants in trade bearing the name Melocactus disciformis all belong to Melocactus conoideus.

Cheers,
Marlon Machado.

Institute for Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
North Lincs Mike
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Re: What would you like to know about Melocactus?

Post by North Lincs Mike » Fri Oct 19, 2007 8:24 pm

Hi Marlon.

It's good to see you on the Forum and welcome. Melos are my favourate cacti. Thanks so much for this initiative which is most informative. I enjoyed your talk at our last convention and am looking forward to reading your articles.

My collection includes several Melos including a very long spined ernestii which won a couple of BCSS Best in Show Diplomas during the summer.

At the BCSS judges course I had a chat with George Thompson from Scotland who is next year due to publish a book on Melos. He like Ernie,
above, has recommended watering during the winter. Mine are kept in a fully insulated (foil faced foam panels up to eaves and heavy bubble wrap above) 8ft by 10ft greenhouse hopefully kept at 15C as George recomended.

Should they be allowed to dry out between watering in the winter. Should I also water regularly or even keep damp my 2007 BCSS seedlings and is 15C necessary or as I think you suggest is 10C adequate.

Mike
Newish collector/grower; mixed lot in a new 12x18 g/h and my old re-erected 10x8 - good job I didn't sell it !
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Trevor
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Re: What would you like to know about Melocactus?

Post by Trevor » Sat Oct 20, 2007 7:17 am

Thanks for the ID Marlon !

This turned out to be a very informative thread. I'll be sure to make sure my next lot of Melocactus seeds are sown, and kept, very damp !
Trevor
With a 'Downunder' collection of Cacti and Succulents in Melbourne, Australia.
Philip
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Re: What would you like to know about Melocactus?

Post by Philip » Sun Oct 21, 2007 11:34 am

Hi

I have a few dozen melos :baringt: not counting seedling.

They spend the summer in the greenhouse and come into the conservatory for the winter. In fact they?ve recently come in as I like to leave them out as long as possible, but once my heater starts working time to bring them in. This mean that they do get temps below the normally accepted 10C but I have found this isn?t a problem so long as the next day the warm up quickly and the temp is never close to freezing (the heater is set to 7C to tell me to bring in the Melos before I lower the temp for the winter)

If people want a Melo I recommend M. Matanzanus for a beginner as they mature with a diameter between 3 and 4 inch. I have some Echnopsis that are bigger the my M. Matanzanus and they?re still growing ;)

Looking after Melos is not much different that ordinary cactus, well drained soil, I use 50% chick grit and 50% JI3 in shallow pots (my biggest pots are only 4 inch high and they have mature 20+ year specimens in) water a lot in summer and some in winter. I watch mine weekly and when they show any sign of losing their ?plumpness? they get some water in the winter. Temp never close to freezing.

My last mature one that lost it roots took over 18 months to reroot, I though I was going to lose it, but over the second winter it rerooted

Seedling are easy to germinate and grow. I find it?s the first winter that I lose lots, I think I should slow earlier in the year to give them more growing time, but I?ve not got round to using grow lights, used heated propagators.

My spare seed this year is already promised elsewhere, I?m not even selling any on ebay, but if people want some M. Matanzanus I can make some available via the BCSS Forum Seed Pool if it?s still running.


[attachment 7595 M.Matanzanus.jpg]
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Marlon Machado
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Re: What would you like to know about Melocactus?

Post by Marlon Machado » Sun Oct 21, 2007 3:20 pm

Hello Mike,

Thanks for your message. This thread is being very useful for me as well, it is great to hear the experiences of other people on growing Melocactus. My advice on how to grow them is based on my observations of the plants growing in habitat, and in my experiences in growing these plants in Brazil, where the conditions are quite different from Europe.

I believe the plants should be allowed to dry out between waterings. What is not good is to allow the substrat to become bone-dry, and not giving the plants any water during the whole winter, because then there is the risk of the plants losing their roots. Regarding the temperature, 10?C is just a suggested minimum - naturally, the higher the temperature, the better for these plants. Also, this is not to say that the plants will colapse if the temperature gets lower than 10?C, the plants will survive lower temperatures, perhaps down to 0?C, but only for short periods of time.

As for the seedlings, I think you should water them regularly and provide them with warmer temperatures than your mature plants, because they are still quite young.

Cheers,
Marlon Machado.

Institute for Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
Marlon Machado
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Re: What would you like to know about Melocactus?

Post by Marlon Machado » Sun Oct 21, 2007 3:30 pm

Hi Philip,

Thanks for sharing your experience on growing Melocactus, I would suggest the same treatment that you give your plants.

Your Melocactus mantanzanus looks great, well done!

Cheers,
Marlon Machado.

Institute for Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
Marlon Machado
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Re: What would you like to know about Melocactus?

Post by Marlon Machado » Sun Oct 21, 2007 5:22 pm

Here is a picture of the habitat of Melocactus conoideus at Vit?ria da Conquista, Bahia. This region can get temperatures down to 0?C during the winter, although the average minimum temperatures are around 10?C.
Cheers,
Marlon Machado.

Institute for Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland.
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iann
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Re: What would you like to know about Melocactus?

Post by iann » Sun Oct 21, 2007 5:38 pm

It amazes me that habitat Melocactus plants always seem to be immaculate, not like those beaten up Copiapoas and Echinocactus you see ;)
Cheshire, UK
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