May EcoQuest - Mystery of the Star-lily
Spring is finally here! One of the showiest spring-blooming plants in the Denver-Boulder metro area in early spring are the star-lilies, Leucocrinum montanum. Star-lily is the only member of the genus Leucocrinum, and is found throughout western North America in grasslands and shrublands. It is also often called sand-lily because these plants mostly grow in sandy soil. Despite its common name, star-lily is more closely related to asparagus than it is the true lilies. The name star-lily comes from the resemblance of these flowers to lilies – both have six perianth parts or tepals.
Star-lilies are rather unusual in that the fruit matures below-ground. In fact, once the plant has finished flowering in late May or early June, the entire aboveground portion of the plant withers away. The maturing fruit remains buried below-ground among the fleshy roots. Once the fruit is ripe, just how the seeds of star-lily are dispersed is a mystery – some speculate that the seeds are pushed out of the soil by new growth the following year, but others have suggested that the seeds are released from the fruit when the sandy soil surrounding the plant is worn away. One additional hypothesis is that ants or other insects transport the buried seeds food, and in the process replant them away from the parent plant. But, the seeds of star-lily offer no reward of food for ants, so this scenario seems unlikely.
Adding to the mystery of the star-lily is a lack of knowledge about what is pollinating these flowers for fruit to be produced. Some think that the flowers are pollinated by hawkmoths, which are attracted to the white flowers, and that are visible at dusk. The long floral tube of star-lilies could offer some kind of reward at the base for hawkmoths too. Or perhaps star-lilies self-pollinate, relying only upon themselves to produce seeds for the next generation. This is definitely a plant that needs additional study!
See if you can locate some star-lilies and help Denver Botanic Gardens by photographing as many plants as possible in the month of May. See if you can spot any insects that could be pollinating the flowers and photograph those as well as part of your observations. Post your findings to iNaturalist so they will automatically be added to the Denver EcoFlora Project.
