SAN FRANCISCO — Crowds lined up in San Francisco on Wednesday to see — and smell — the blooming of an endangered tropical flower that releases a pungent odor when it opens once every several years.An Amorphophallus titanum, also known as a corpse flower, began blooming Tuesday afternoon at the California Academy of Sciences, a research institution and museum.The plant blooms for one to three days once every seven to 10 years. During the bloom, it releases a powerful smell described by…