Sempervivum calcareum is a species of Sempervivum that has been relatively popular for a while. Most of the calcareums that I have seen tend to look similar, being characterized by a whitish green with sharp, dark tips. I'm opening this thread for people to post pics and discuss their various calcareums.
I think that calcareums are a bit more fragile or sensitive to conditions than your typical Sempervivum. I know that I have lost several types of calcareums overwintering over the years.
Here is a partial list of the calcareum varieties, which I'll update from time to time as I hear about others. * means I have it in my collection, + means I am looking to add it.
+ S. calcareum (the species type)
+ S. calcareum ex Guillaumes (S. calcareum from Guillaumes, France)
+ S. calcareum 'Extra'
+ S. calcareum from Route d'Annôt, France
* S. calcareum 'Greenii'
+ S. calcareum 'Limelight'
+ S. calcareum 'Monstrose' (or sometimes 'Monstrosum')
* S. calcareum 'Mont Ventrox'
* S. calcareum 'Mrs. Guiseppi'
+ S. calcareum 'Nigiricans'
+ S. calcareum 'Nigrum'
* S. calcareum 'Oddity' (earlier name S. calcareum 'Grigg's Surprise')
* S. calcareum 'Pink Pearl'
* S. calcareum 'Sir Wm. Lawrence'
+ S. calcareum 'Spinulifolium'
+ S. calcareum 'Tip Top'
Once you've seen a few of the calcareums, you'll start to recognize the type. However, some caution is needed before assuming a cultivar is a calcareum as there are other Sempervivum species with sharp dark tips that can look very similar.
Below is a pic of S. calcareum 'Greenii' and a closeup of the same plants. I'll add some more pics in the future of the ones I have.
S. calcareum 'Greenii'
