A different type of bouquet—a male Encephalartos woodii produces a showy cluster of bright cones. Photo by Gary Roberson. | The Huntington Library, Art Museum, and Botanical Gardens.
When it comes to romantic gestures, roses and orchids often take center stage on Valentine’s Day. But in the plant world, few species can rival cycads as a symbol of everlasting devotion. These ancient plants—often mistaken for palms or ferns but closer relatives of such conifers as pines and fir trees—have withstood the test of time, surviving ravenous dinosaurs, ice ages, and other cataclysmic events. Today, however, habitat loss, poaching, and declining pollinator populations threaten their survival, placing cycads among the most endangered organisms on Earth. Thankfully, their unconventional charm has inspired conservation efforts worldwide, including at The Huntington.
Most plants are monoecious, meaning their flowers contain both male and female reproductive organs, or a single plant can produce male and female flowers at different times. An individual plant’s ability to produce both pollen and seed increases the species’ reproductive capacity. In contrast, cycads are dioecious, with individual plants producing either male cones that contain pollen or female cones that bear seeds. This means reproduction requires both male and female plants. One particularly fascinating cycad species is the enigmatic Encephalartos woodii, which has no known female counterpart.
Ginkgo biloba has existed about as long as cycads—some 300 million years. Like cycads, these trees are also dioecious, which means that they have male and female reproductive organs in separate individuals. Insights gained from studying cycad reproduction may shed light on this species as well. Illustration by Jane Levy Campbell. Used with permission from the artist.
The Lonely Cycad
Only one wild specimen of E. woodii has ever been found. The lone, multistemmed male cycad was discovered in 1895 by botanist John Medley Wood on the edge of the Ngoye Forest in South Africa. Efforts to locate a female, or any other wild individuals, failed. By 1916, the original plant was relocated to the Durban Botanic Gardens in KwaZulu-Natal, South Africa, where it continued to thrive.
Over the years, Durban shared offsets, which are genetically identical to the parent plant, with other botanic gardens and, in some cases, private collectors, including the late Loran Whitelock, a renowned cycad expert. Whitelock donated his estate, including his collection of some 1,500 cycads, to The Huntington. The extensive cycad terrace adjacent to the Huntington Art Gallery is home to the collection, which includes two E. woodii.
Two of The Huntington’s four E. woodii plants came from the Loran Whitelock estate. One of the pair is pictured here in the Whitelocks’ home garden just above the stone lantern. Photo by Gary Roberson. | The Huntington Library, Art Museum, and Botanical Gardens.
Gary Roberson, lead project gardener at The Huntington, oversaw the transfer of plants from the Whitelock estate and recalled the day in 2015 that the first E. woodii was relocated.
“It was like witnessing a comet—something that happens once in a lifetime,” Roberson said. “I felt that same sort of wonder when we were loading the E. woodii at Loran’s house, taking it down the driveway, and loading it on the truck.”
Left: Transporting the two E. woodiis from the Whitelock estate was a momentous occasion. Photo by Gary Roberson. Right: Gary Roberson next to a successfully transplanted E. woodii. Photo by Brandon Tam. | The Huntington Library, Art Museum, and Botanical Gardens.
Propagation Efforts: Challenges and Innovations
Currently, more than 500 E. woodii individuals exist globally. However, these individuals are all genetically identical clones of the original male plant at Durban, so they lack the genetic diversity crucial for the long-term health and survival of the species. To address this, a female plant is needed. In the 130 years since the discovery of the lone male E. woodii, advancements in technology have revolutionized this quest.
Pollen from the E. woodii males is routinely collected to share with other botanical gardens and collectors who are growing hybrids. Video by Sandy Masuo.
To increase genetic diversity among E. woodii, scientists are exploring three approaches:
1. Backcrossing with Related Species
One traditional horticultural method involves crossing male E. woodii pollen with the seeds of a closely related species, Encephalartos natalensis. Female offspring from these crosses are then pollinated with E. woodii pollen, gradually increasing the genetic makeup of E. woodii in subsequent generations. This process, called backcrossing, relies on patience because it can take 10 to 15 years for these cycads to produce their first cones. The method eventually produces a plant that is very close to but never entirely the same as E. woodii.
A female Encephalartos natalensis produces colorful seed cones. This species is a close relative of E. woodii. Photos by John Trager. | The Huntington Library, Art Museum, and Botanical Gardens.
2. Using Drones and Artificial Intelligence to Locate Female E. woodii
New technologies, including drones and AI-driven plant identification software, are being used to scan potential habitats for female E. woodii in the wild. This high-tech approach replaces the labor-intensive fieldwork of the past, offering hope of discovering a long-lost mate for the lonely male.
3. Genetic Science and Sex Reversal
Some scientists believe that it may be possible to create a female E. woodii through the magic of genetic science. Since 1932, 33 cases of sex reversals have been recorded in 17 cycad species. Each instance involved individual plants in cultivation that were exposed to extreme conditions, such as a dramatic temperature shift, drought, or transplant shock. However, a cycad sex reversal—a rare and unpredictable occurrence—has never been replicated in laboratory conditions. Nevertheless, scientists, including The Huntington’s cryopreservation botanist Raquel Folgado, are curious about the phenomenon.
“I’m interested in any response to abiotic—physical rather than biological—stresses in plants,” Folgado said. “But I am not 100% confident that this is what is really happening in these cases. At The Huntington, we haven’t seen any sex changes among the many cycads transferred from the Whitelock estate, despite the upheaval of relocation and the drought conditions here.”
A flush of new growth emerges from the E. woodii. The meristem is the growth center of the plant and cannot be harvested for lab use without seriously damaging the plant. Photo by Gary Roberson. | The Huntington Library, Art Museum, and Botanical Gardens.
To test this sex-change theory, researchers would need to systematically expose cloned plants to the conditions believed to trigger sex changes. However, obtaining suitable test subjects is a challenge. Folgado is currently working on cloning E. woodii through micropropagation—a laboratory technique that can produce large numbers of new plants from a small amount of growing tissue. But the process is time-consuming and faces a significant obstacle. The ideal tissue for this process is the cycad’s meristem tissue, which functions like stem cells in animals because it contains undifferentiated cells capable of developing into new plant parts.
Unfortunately, in the case of cycads, harvesting meristem tissue is highly invasive and potentially fatal to the source plant. Given that The Huntington has only four specimens of E. woodii—an extinct species in the wild—sacrificing one for experimentation is not an option. Instead, Folgado has had some success propagating clones from the leaflets of young E. woodii fronds, but it will take time before enough clones survive and mature for testing under extreme conditions.
Through micropropagation, many plants can be cloned from a small amount of growing tissue. The vials on the left are propagules introduced in tissue culture from Encephalatos woodii leaflets. The beakers on the right contain plants regenerated from Ceratozamia miqueliana callus tissue, which is like animal stem cells. Photos by Raquel Folgado. | The Huntington Library, Art Museum, and Botanical Gardens.
The Future of E. woodii
The survival of this cycad species relies on the fascination that plant lovers, from passionate hobbyists to enthusiastic botanists, feel for it. Brian Dorsey, senior systematic and conservation botanist at The Huntington, expresses admiration for what this lonely cycad represents—whether efforts to make a match for it succeed or not.
“E. woodii may never return to the wild,” he said. “However, studying it may provide valuable insights into the evolution of sexual determination in cycads and where that system came from, which is one of the coolest things for me. That system likely predates cycads and was in the ancestor of living seed plants, which suggests it goes back at least 300 or 400 million years.”
This extraordinary species serves as a living link to Earth’s prehistoric past and a reminder of the importance of plant conservation. Whether through traditional horticulture, cutting-edge technology, or genetic science, the fascination with E. woodii continues to drive efforts to preserve this botanical marvel for generations to come.
Gardener Josh Quan and volunteer Sierra Kerr examine cones from a male E. woodii. Although a female of the species has yet to be found or created, the pollen is valuable to researchers and plant breeders who are interested in growing hybrid plants. Photo by Gary Roberson. | The Huntington Library, Art Museum, and Botanical Gardens.
Sandy Masuo is the botanical content specialist at The Huntington.