Hi Dennis. I used to keep lots of terrariums when I was a kid. In one I successfully grew Lycopodium obscurum for years. Now, I don’t have any terrariums as such, but I do have two large ornamental bottles, one pear shaped and the other flat pumpkin shaped. The one which is pear shaped has a plant of Begonia masoniana which has been in that jar for about thirty years. It gets watered two or three times a year and that’s it. Otherwise it’s utterly carefree. The plant has filled the space inside the jar, and it’s very decorative. It even blooms occasionally. The low pumpkin shaped jar is used for various tropical Selaginella. These too are utterly carefree: they go for years without attention other than an occasional admiring glance or a splash of water. . They look like moss, and they have filled the space inside the jar with their bright green mossy foliage. The ones I grow are not the big tropical spike mosses, but rather the smaller ones which start out as a tidy clump which expands indefinitely. Names to look for (they might not be valid names) are Selaginella kraussiana, S. flabellata, S. emiliana and others. Some of these are available in crested forms, variegated forms or forms which produce very compact growth. One called S. uncinata produces foliage with an oil-slick effect – iit’s sometimes called blue peacock spike moss. They are all cool little plants, and as long as they don’t dry out, nothing seems to bother them. There are a million and one other choices for terrariums, but the ones above are my current favorites. If I had more room and more of those ornamental bottles, I would have Adiantum ferns in some. Bulby things, because of their general need for good drainage and typically strongly seasonal growth, don’t strike me as good choices for a terrarium which is watered, but at one time I grew some Ledebouria socialis that way and they did well. I like your idea of putting the cactuses (and their spines) behind glass. Jim McKenney jimmckenney@jimmckenney.com Montgomery County, Maryland, USA, 39.03871º North, 77.09829º West, USDA zone 7 My Virtual Maryland Garden http://www.jimmckenney.com/ BLOG! http://mcwort.blogspot.com/ Webmaster Potomac Valley Chapter, NARGS Editor PVC Bulletin http://www.pvcnargs.org/ Webmaster Potomac Lily Society http://www.potomaclilysociety.org/