New succulent species named by UC Santa Cruz botanist

SANTA CRUZ — Emeritus Director of Research at the UC Santa Cruz Arboretum & Botanic Garden Stephen McCabe has helped name yet another succulent species in the genus Dudleya, called Dudleya chasmophyta, or the crevice-loving Dudleya, which is found exclusively on a cliff band in Orange County.

This is the fifth species of the genus that McCabe has had a part in naming over more than four decades of research and comes on the heels of two others named last year — Dudleya delgadilloi in honor of a prominent Mexican botanist, José Delgadillo Hernandéz, professor and director of the herbarium at the Universidad Autónoma Baja California en Ensenada — and Dudleya cochimiana in honor of the Indigenous people known as the Cochimí.

The discovery of the new succulent species came about after McCabe had become aware of some Dudleya research conducted around 1950 in Orange County. The researcher, David Verity, had studied Dudleya plants in the area but failed to collect and save specimens. After reading into it further, McCabe suspected the researcher had conflated distinct species of the succulent and wanted to see the plants for himself.

“Because I am concerned with the genus, I thought that in order to understand everything about them, I ought to go and visit the site,” said McCabe. “I tried finding it on my own and couldn’t.”

McCabe sought the help of Fred Roberts and Ron Vanderhoff of the California Native Plant Society, and they provided McCabe with their local knowledge and helped arrange access through the U.S. Forest Service to the cliff-loving plants. McCabe and Roberts then bushwhacked their way through dense foliage and poison oak to find the plant’s steep habitat.

“We got permission from this landowner to come up from the bottom, and there had been a fire there,” said McCabe. “The vegetation had recovered from the fire and included Ceanothus, which has really sharp thorns on it, so it was really unpleasant.”

When naming the plant chasmophtya, McCabe along with colleagues Kristen Hasenstab-Lehman and Matt Guiliams of the Santa Barbara Botanic Garden, veered away from naming the plant after a specific person or place, but rather chose to derive its new name from one of the plant’s distinct features.

“It’s tricky because so many Dudleya grow on rocks but this particular species only grows on steep cliffs,” said McCabe. “I had named one other species after Jimi Hendrix but there’s a movement to not name things after people but to try and name them after some feature of the plant and in this case crevice-loving seemed like a good moniker.”

The name of the cliff-loving succulent was officially published in the California Botanical Society journal Madroño earlier in March and another scientific paper by Hasenstab-Lehman, Guilliams, and McCabe describing Dudleya chasmophyta’s genetic makeup is still in the works.

“They’ve done some great genetic work that shows that it is really separate from everything else,” said McCabe.

Because the Dudleya chasmophyta plant lives in such a limited and steep area, poaching may not pose a threat to it as it does some of its succulent cousins, but giving the succulent a name and saving its seeds will help in conserving and protecting the plant and saving it from the potential effects of the changing climate.

“Without the name, many of the agencies will not recognize it as something that needs protecting,” said McCabe.

With another newly named Dudleya under his belt, McCabe is excited to continue his research on the Channel Islands where Dudleyas were devastated by non-native animals such as cows, deer and pigs, brought by humans in the past. The animals were removed over time, however, and the many Dudleya species living there have slowly started to grow back and McCabe is sure there are some succulents there that have yet to be named.

“The Nature Conservancy is going to give me a ride on a helicopter to the Channel Islands in May to try and document a potentially new species,” said McCabe.