The enticement of desert wildflowers was definitely on my mind when I applied for my job at theNAT.  To my delight we had the requisite rains this winter, and my first March in San Diego produced a “super bloom.” I was excited to join the hordes of flower peepers heading to Anza-Borrego Desert State Park.

At the Museum, we love it when it rains. TheNAT provides the perfect rainy-day activity, and we’re delighted to welcome foul-weather visitors. Our scientists also know that rain brings the region to life. 

With the right amount and timing of rain the plants have a good year. The insects that eat them also have a good year. The birds, lizards, and other animals that eat insects follow, and of course their predators benefit in turn. We should have one fat and happy bioregion this year.

For many years, desert plants can lie dormant as seeds or bulbs beneath the surface waiting for the perfect conditions. Seeds can be numerous in desert soil, with thousands found in a square meter.  Although most of us marvel at the carpets of purple Desert Sand-verbena (Abronia villosa), yellow Desert Sunflower (Geraea canescens), and white Dune Evening-primrose (Oenothera deltoides), botanists find great joy in the less showy spring blooms.

I invited myself along on Jon Rebman’s Botany Department field trip to the desert. Jon and his hardy crew of volunteers planned to spend several days collecting in Imperial County. I opted for 24 hours with them, and knew this would not be a typical super bloom pilgrimage when we made our first stop.

Jon pulled our caravan over to the side of the road north of Ocotillo, California (population 266) next to a patch of nondescript shrubs, with no flowers in evidence. We were looking for Pilostyles thurberi, a small parasitic wildflower that lives entirely inside the stem of another plant, White Dalea (Psorothamnus emoryi). Pilostyles is so obscure that it basically lacks a common name (although it is referred to as Thurber’s Pilostyles, an English translation of the scientific name). It also lacks roots, stems, and leaves. The plant depends entirely on its White Dalea host for nutrition and water. Tiny flowers appear like dark pimples that pop through the White Dalea stems. Pilostyles provided our first wildflower show, a modest warm-up act for what was to follow.

Of course we saw plenty of flashy wildflowers. Beavertail Cacti (Opuntia basilaris) were blooming in many shades of pink and magenta, and Brittlebush (Encelia farinosa) looked like yellow flower baskets set along the side of the road. Our boots and pants legs were covered in sticky pollen from the great swaths of Brown-eyed Evening-primrose (Chylismia claviformis).

However, the Botany crew was most excited about the more obscure plants. 

My personal favorite was the threadplant. As the name implies, Nemacladus orientalis is nearly invisible. It grows low to the ground, and to the untrained eye looks like someone emptied a hairbrush on the desert floor. The white flowers were the size of large sand grains. However, when viewed through a magnifying glass these brown-tipped beauties looked like miniscule orchids.

The field expedition was organized to re-survey one of the 3-mile by 3-mile grid squares, “Q 29” in the San Diego County Plant Atlas, and to visit some other low desert areas in Imperial County. It had been at least five years since the area was last surveyed and many years since the last big desert bloom. Jon and crew added 26 new species to the grid list and documented them with specimens for the herbarium. In all, 234 new specimens were collected in the low desert areas during this entire trip. As unskilled labor, I helped prepare the plants for preservation and also washed the dinner dishes.

On the way back to San Diego, my colleague Ann Laddon and I slipped into Anza-Borrego Desert State Park to gawk at the floral display along Henderson Canyon Road. We found parking between a group of bikers and a row of campers and joined the crowd peering at the improbably beautiful and seemingly endless field of flowers. We knew that somewhere under the explosion of purple, yellow, and white there were other species—tinier but certainly no less remarkable.

On the hunt for Pilostyles parasitizing White Dalea.

Pilostyles flowers.

It was easy to get distracted by flowering Beavertail Cactus, Brittlebush, and Ocotillo

The badge of super bloom honor: we were plastered with characteristically sticky Brown-eyed Evening-primrose pollen.

Preparing cacti for the plant press can be a “bloody, painful experience,” so Jon Rebman demonstrates good technique to Ann Laddon.

Botanical fieldwork continues beyond nightfall. We spent the evening processing plants from the field presses to prepare them for drying.

Find the threadplant! Hint: it is next to the white rock in the center of the photo.

Threadplant, Nemacladus orientalis.

Threadplant, Nemacladus orientalis.

Breakfast in the desert. Ann Laddon and her 4x4 camper provided the chase car for the expedition.

The group photo with the Botany truck includes: Victoria Marshall, Louise Russell, Judy Carlstrom, Anna Arft, Jim Roberts, Judy Gradwohl, Ann Laddon, and Marty Blake-Jacobson

The super bloom along Henderson Canyon Road in Anza-Borrego—pretty, but not as exquisite as threadplants.

Posted by President and CEO Judy Gradwohl on March 31, 2017