April 12, 2014

Sand Blazing Star a real show-stopper

Sand Blazing Star (James Cornett )
James Cornett
Desert Sun


Under favorable conditions, Sand Blazing Star is one of the desert’s most striking wildflowers.

While other ephemerals may collectively produce spectacular displays, a single Sand Blazing Star can be a show all in its own. In wash environments, where both local winter rain and runoff can provide a seasonal bounty of moisture, an individual plant may exceed two feet in diameter, grow nearly as high and produce many dozens of pale-yellow flowers. Even the most uninterested layperson will be impressed with a Sand Blazing Star in full bloom.

Like nearly all members of the Loasa Family (Loasaceae), Sand Blazing Star has tiny barbed hairs on its foliage. The leaves feel rough to the touch and easily adhere to clothing, almost like Velcro, if contact is made. It is generally believed a function of barbed hairs is to make leaves and stems unpalatable to animals.

Wildflower enthusiasts cannot help but notice flowers of Sand Blazing Star resemble those of Ghost Flower, Mohavea confertiflora. Examination reveals both species have flowers similar in size, shape and color. This similarity is in spite of the fact the two species are in completely different plant families (Mohavea is placed in the Figwort Family, Scrophulariaceae). The two species also often grow in the same area as well. (For example, both grow together in the wash behind my home.)

Biologists believe the ghost flower has evolved an appearance that mimics Sand Blazing Star. But for what purpose?

Sand Blazing Stars produce nectar in their flowers to attract pollinators. Ghost Flowers don’t produce nectar but attract selected bee pollinators by having a similar appearance and by having a dark spot near the bottom of each flower that looks like a female bee. Male bees enter a Ghost Flower because they think there is a female in it. By the time a male realizes she’s not there, a trap-like structure has stuck pollen onto the bee’s back where he can’t reach it. He exits the flower and eventually flies on to another Ghost Flower, inadvertently pollinating it in his quest for nectar, pollen or a female bee.

Although the bee gains nothing, the Ghost Flower achieves pollination without having to produce nectar or having its pollen consumed. The fact that Sand Blazing Stars are more common than Ghost Flowers means that bees will be successful more often than not in finding females and nectar, in spite of wasting some time in Ghost Flowers.

Humans can distinguish the two species by examining the structure of the flower. The petals of the Ghost Flower are fused to form a slightly elongated cup. Sand Blazing Star has distinct petals that overlap but are not fused together. Look for both species in desert washes.