Hi,
What about Mammillaria duwei for nº 3?

Hi Vicent,
This plant reminds me of P. tuberosus, this seems to be a very variable species so perhaps its just a form of it.

If you would like to know the backgrounds of cactus study, it might be interested to read the 'old' books as well, such as Britton and Rose, Ritter and Backeberg. These 'old' books can be downloaded here: http://www.cactuspro.com/biblio/

Hi,
These are the typical flowers for a Cleistocactus. A good point to start would be this website.
Of you really want to know a lot about them, you should buy some good books. The new cactus lexicon would be a very good choice, but might be a bit difficult for a beginner.

Hi,
As your seedlings seem to be green near the seed remains (giving them shadow), I'm quite sure they have been burned by the sun. Cactus seedlings need to be in the shadow for the first year, no direct sun at all. Also your substrate looks quite weird and dry for cactus sowing.

fanaticactus wrote:So the ID is not definite, but it is narrowed down to either uebelmannianus or crassigibbus?

I think so, that it is one of these two species.

Daiv, we all keep learning new things The more you learn the less you know.

Daiv, Notocactus uebalmannianus can have both purple and yellow flowers and both grow just side by side in habitat. Just check the pictures here: http://forum.tuinadvies.be/forum_topic.php?hid=10&sid=28&tid=31096&hl=uebelmannianus I'm not knowledgeble enough in these Notocactus to tell a...

Hi,
That's a Cylindropuntia, but no clue what species.

Hi,
I would say this second one is that spineless cultivar of Notocactus uebelmannianus.

Hi,
If you refer to those large and hard patches, that's not scale indeed, as Ian already told you. That's probably an epidermal fungus like Phoma causing this.

Could nº5 be a young Stenocereus dumortieri?

Hi,
The first one is an Oreocereus, the second one is Opuntia monacantha monstruosa variegata, the third one is another monstrose Opuntia. Plant nº 4 is a Mammillaria and the last one is possibly a TRichocereus spachianus with an aeral root.

Opuntia robusta then? This species seems to be quite abundant in southern France so it wouldn't be that rare to show up in the Netherlands then.

Hi,
That opuntia does look like O. ficus-indica, but on such small plant without flowers nor fruits it's almost impossible to be sure about the name.

Several Espostoa species have those short, dark spined under the whool. I currently have nice seedlings of E. lanata ssp. lanianuligera that have those short brown spines as well.
I would say, wait 10 or 15 years till flowers appear to get the ID right