Despite both its attractiveness and the year it was planted (~1988), I only noticed butter lily (or Christmas lily) in the UBC Alpine Garden for the first time last week. The epithet modesta means “unassuming” or “moderate”, so perhaps I overlooked it in favour of bolder plants in years past.
The Pacific Bulb Society has a Wiki entry on Littonia; it's worth visiting, as it shares photographs of this South African species as it grows from seedling to fruit. It also includes an image of its tuber.
The tendril-like leaf tips are described botanically as a “cirrhose leaf apex” (see Jim Croft's Botanical Glossary). Functionally, they act as they appear to act, helping the plant “climb” (or at least be supported) as it grows in height.