It was 2013, and botanist Seana Walsh had a pollen problem. She was working at the National Tropical Botanical Garden on Kaua’i, trying to breed a severely endangered Hawaiian plant. Brighamia insignis is known as the ‘ōlulu in Hawaiian; in English, it’s jokingly called “cabbage on a stick.” But when Walsh tried to collect pollen from the staminal columns of different flowers in the garden, almost nothing came off. The little pollen Walsh did collect turned out to have extremely low viability—similar to low sperm count in animals. For the ‘ōlulu, this meant low odds of the plants successfully reproducing.
The urgency of Walsh’s work came from an alarming fact: Only one ‘ōlulu plant was known to exist in the wild, hanging from its preferred cliffside habitat on Kaua’i’s Nā Pali coast. Walsh had never seen that particular individual, but she’d visited other plants in botanical gardens across the Hawaiian Islands. Now, she was studying the plant’s breeding strategy (likely accomplished with help from moths in the wild) and attempting to coax the reproductive process along by hand.
Walsh wasn’t sure what had caused the paltry pollen harvest. Maybe it was the result of environmental differences between the botanical garden and the natural habitat—it might be hotter or drier, for example, or lacking certain nutrients in the soil. Or maybe there was some Hapsburg effect happening: the plants had experienced too much inbreeding.
But what if Walsh could play matchmaker for Brighamia insignis plants with drastically different genes? Botanical gardens and private greenhouses around the world have cultivated thousands of them and other plants, in part to study and preserve species that are rare, or potentially useful. Maybe she could mix and match distinct individuals from the same species, creating a more genetically robust population of plants, and then return those healthy cabbages to the wild.
