Leichtlin's Mariposa Lilly (Calochortus leitchlinii) is one of the coolest and most distinctive flowers in the Sierra. If you see it in bloom, it's hard to confuse it with anything else except the much more rare, and inappropriately named, Ordinary Mariposa Lilly (Calochortus invenstus). I suppose it's ordinary somewhere outside the park. Botti, p. 386, gives the common name for Calochortus leichtlinii as Subalpine Mariposa Lilly, but most books will list it as I have.