By Jon Letman, Editor
Writing in A Monographic Study of the Hawaiian Species of the Tribe Lobelioideae Family Campanulaceae in 1919, botanist Joseph Rock described the genus Brighamia as “one of the most curious Hawaiian Lobelioideae, though not one of the handsome ones.” Rock noted that renowned American botanist Asa Gray named the succulent genus for Dr. William T. Brigham, the first director of Honolulu’s Bishop Museum.
Describing the species that would later bear his name — Brighamia rockii — the Vienna-born botanist wrote unflatteringly: “It certainly is a most grotesque plant.” German botanist William Hillebrand, who preceded Rock in Hawaii by half a century, compared Brighamia to a “cabbage put on a fence post.”
Lobeliads, to which Brighamia belongs, found their way to the Hawaiian Islands some 13 million years ago in a single migration, evolving into 159 endemic taxa of Campanulaceae (bellflower family).
Rock was certain that Brighamia migrated from Australia, perhaps as one of the last of the Lobeliads to arrive in Hawaii and, as a result, lacked sufficient time to speciate before animals and humans began to present a threat.
In the early 1900s Brighamia was classified as a monotypic[1] genus although botanist Charles Forbes differentiated between the Brighamia on the cliffs of Kauai with their yellow flowers which inspired the species name citrina, and the Molokai form which bears white flowers. Today they are recognized as two species, B. insignis and B. rockii respectively. In Hawaiian they’re best known as alula or puaala.
Viewed side by side, they differ only slightly in appearance except for the color of the flowers. Other differences — calyx lobe size, leaf shape, seed surface — are very subtle.
Rock documented Brighamia’s habitat in the early 20th century — the steep, windward cliffs of Niihau, Kauai, Molokai, and Lanai. He reported seeing Brighamia on the cliffs of the Kalaupapa peninsula of Molokai and “on almost bare rockwalls between Kalawao and Waikolu, within the spray of the sea, only a few feet above the mighty breakers of the Pacific.”
He also reported Brighamia growing in the dry, rocky gorges at the entrance to Molokai’s Halawa Valley. French botanist Jules Remy collected a single specimen in the early 1850s and the last Brighamia seen on Niihau was in 1947.
It was another botanist, Harold St. John, serving as a scientific advisor for NTBG in the mid-1970s, that first suggested to a young nurseryman and field botanist named Steve Perlman to search for, collect, and grow Brighamia. Perlman was unfamiliar with the genus but began searching the known habitat.
Over the next three decades, Perlman, along with fellow NTBG botanist Ken Wood, climbed, rappelled, hand pollinated flowers, and later collected the tiny seeds as they defied gravity, roping along the vertigo-inducing cliffs of Kauai and Molokai.
Among their findings, they located several plants along the upper cliffs of Molokai’s Wailau Valley, but those plants are now gone. They spent years searching for B. rockii in the Halawa Valley, but found none. Perlman and Wood also collected seeds on Huelo Rock off Molokai but those plants are now gone. Perlman spotted B. rockii on Molokai’s Kaaloa cliffs and a few plants may remain.
The largest remaining wild population of B. rockii is on the cliffs of Waiehu, east of Wailele falls, but a series of landslides has rendered the area too hazardous to work and NTBG botanists haven’t been back since they last roped down to the site in 2011. The last known seed collection of B. rockii was by staff of the Plant Extinction Prevention program in December 2014. Today there are an estimated 30 plants remaining on Molokaii’s seacliffs.
On Kauai, B. insignis populations crashed after Hurricane Iniki devastated the island in 1992, with the last plant dying on Mt. Haupu in 2002 and the last one seen on the Na Pali Coast around 2015.
With the threat of landslides, hurricanes, feral goats, rats, and the loss of the suspected pollinator, a giant sphinx moth, wild Brighamia spp. hover just above extinction.
Between Kauai and Molokai, on the island of O‘ahu, there have never been credible claims documenting Brighamia. If it ever did exist there (nothing suggests that is so), one could posit that with limited field collectors and the difficulty of accessing steep cliff terrain, any plants might have vanished before they were discovered.
Spanning more than 30 years, NTBG botanists have collected seed from all Brighamia spp. colonies, making repeat visits to conduct pollen exchanges by hand, and returning to collect seed for deposit at NTBG’s Conservation and Horticulture Center. Garden staff determine if seeds are put into storage or propagated for outplanting. NTBG usually has anywhere from 50 – 250 B. insignis and less than a dozen B. rockii in the greenhouse for planting in the gardens.
Multiple attempts at outplanting B. insignis have been made with some of the most successful results in the relatively protected Limahuli Valley which is near their native habitat.
Perlman says, “We would like to have some protected areas to do outplanting of species…the best way to keep that species the same and alive is to put it back where it evolved, where you have the same rainfall and same kind of soil.”
Having hand-pollinated and collected tens of thousands of seeds, NTBG staff have partnered with Kalaupapa National Historic Park on Molokai whose natural resource managers have planted B. rockii on the cliffs as part of restoration efforts.
On Kauai, NTBG’s Seed Bank and Laboratory currently houses over 15,000 seeds from 52 accessions representing B. insignis and more than 11,000 B. rockii seeds from 23 accessions.
Seed Bank and Laboratory Manager Dustin Wolkis notes that Brighamia spp. represent some of the NTBG’s earliest seed collections, going back 24 years. Part of storing seeds at NTBG is conducting germination trials to better understand how long seeds can be stored and how to increase longevity. The seeds are desiccation tolerant but decline more rapidly at -18°C (conventional storage temperature) compared with cool +5°C.
Genetic material is also stored by the University of Hawaii’s Lyon Arboretum Hawaiian Rare Plant Program which has over 100 in vitro Brighamia spp. seedlings, as well as some 20,000 seeds (6,000 B. insignis and 14,000 B. rockii) banked. Additional seed collections are held by the National Laboratory for Genetic Resource Preservation in Colorado, and elsewhere.
For over a century, Brighamia has captured the imagination of botanists and fueled their passion for rare plant conservation. This includes Seana Walsh who, prior to accepting a position as a conservation biologist at NTBG, completed her Master’s thesis on the floral biology, pollination ecology, and ex situ genetic diversity of B. insignis.
Walsh has gone on to help establish collaborations between NTBG, Chicago Botanic Garden (CBG), and others who are conducting ongoing studies of genetic diversity of Brighamia. Based on these results, researchers at CBG are developing and implementing an ex situ conservation management plan for the species that considers lessons learned by zoologists with similar genetic management goals.
Besides outplanting live plants and storing living genetic material, growing B. insignis in cultivation and sharing widely among botanic gardens and the horticulture industry has increased plant numbers to the tens of thousands. These efforts stem from Perlman, who began sending Brighamia seeds to other botanical gardens, first across the U.S. and then in Europe where they caught the attention of commercial nurseries in the Netherlands and elsewhere. According to the sourcing guide PlantSearch, B. insignis is cultivated ex situ in at least 55 botanical collections.
In recent years, B. insignis has taken off as a wildly popular house plant sold in Europe as the “Vulcan palm” or “Hawaii palm.” And while there may be only one B. insignis and just a few dozen B. rockii left in the wild, today there are thousands of B. insignis growing in cultivation, all but ensuring they won’t fade away any time soon.
From a conservation standpoint, commercially grown cultivated plants may not be the ideal end goal, and yet the botanists who have spent decades literally risking their own lives to find, collect, and save these gems of plant evolution say it’s better than the alternative: an endemic plant genus abandoned on remote cliffs, left on its own to slip quietly and unnoticed into the permanence of extinction.
[1] A genus with only one species