I have a young friend who loves bulbs with twirly leaves. Undoubtedly, he will recognize himself here, and he has generously passed on to me some delightful examples Now, we don't usually grow bulbs for their leaves, so this fascination with the curly, twirly ones I can sympathize with, since I love Oxalis for the same reason, in that they have extremely attractive leaves. Oxalis, however, do have lovely flowers, and many of the curly leafed bulbs have flowers that are, how to put it, a bit insignificant. That doesn't matter at all, the leaves are the thing, and they are really wonderful.
Above and to the left is Ornithogalum concordiana (sometimes called Albuca concordiana) from southern Africa with tight curls. It would probably look even better in a hot dry environment. The flowers are white and green, typical of many Ornithogalums, and not that preposessing.
Another curly one is Albuca spiralis, seen here to the right. I bought my original bulbs thus labeled, and have distributed a few under that name, but I am told it isn't A. spiralis but an unidentified Albuca. Here is the original one, with rubbery curls of leaves that are very charming.
The real Albuca spiralis, here on the left, has leaves that are like ringlets. The flowers are also very attractive, yellow striped with green. I grew this amazing bulb from seed to flowering in about six months.
The genus Cyrtanthus has several members that have curly or spiral leaves. Cyrtanthus smithiae is seen to the right, with C. spiralis to the left.
Cyrtanthus herrei doesn't exactly have leaves that are spiral, but they do have a very attractive twist to them.
No-one could ever say that Cyrtanthus flowers were dull, all have extremely showy flowers, so the leaves are an added bonus.
I don't have Gethyllis linearis, but here is a link to a wonderful picture of this bulb in a friend's collection:
http://www.flickr.com/photos/88332547@N03/8175966649/in/photostream
I have read somewhere that spiral leaves are an adaptation to a dry environment or intense sunlight, and I have observed with some of my plants that the leaves are more tightly curled on some days than others.
I have to apologize once again for the formatting. It is a problem with Typepad, and whatever I do the pictures and text rearrange themselves when I publish.