HAWAI'I'S ENVIRONMENT
Rare native plant has many relatives
By Jan TenBruggencate
Advertiser Columnist
Last week's column on the critically rare native tomato relative, Solanum incompletum, or popolo ku mai, led to a number of questions from readers about the once-widespread plant, now found only in the saddle area between Mauna Loa and Mauna Kea. Here is one of them:
Q. "There is a small tomato-like plant which seems to be infesting an area of (Kalopa State Park) ... orangish in color with thorns. I am wondering if this could possibly be the popolo. The thorns were really nasty and someone even told me that it was poisonous ... What do you think?
— Edith Worsencroft, Honomu, Hawai'i.
A. It's hard to tell without having a botanist inspect the plant. There are many tomato relatives in the Islands, including a handful like the popolo ku mai that are native to Hawai'i and found nowhere else, but also a number of imported ones.
U.S. Army
Among the native members of this clan are the endangered O'ahu and Kaua'i forms of Solanum sandwicense, popolo 'aiakeakua, which can grow into tall shrubs with black berries. Another native is the coastal dune shrub known as popolo on most islands and 'akia on Ni'ihau, Solanum nelsonii. Its fruits are black, though there are reports of a red-fruited form from the island of Nihoa in the Northwestern Hawaiian Islands.
The popolo ku mai can only be found in the saddle area between Mauna Loa and Mauna Kea on the Big Island.
Many of the other members of this group are weeds.
A relative that can confuse people is the glossy nightshade, Solanum americanum, which was well known to the early Polynesians as an edible and medicinal plant. It has shiny black berries a quarter-inch or so in diameter. It is called popolo or 'olohua.
However, a very similar looking plant introduced after European arrival in Hawai'i is the Solanum nigrescens, and its fruit is reported to be toxic. Its berries may not be as glossy as those of the popolo.
Neither of these look-alikes is thorny.
One introduced thorny specimen is the lei fruit, kikania, Solanum capsicoides, also known as akaka or cockroach berry. It can grow 3 feet high with half-inch spines and round, bright-orange fruit. Another thorny introduction has yellow fruit an inch or so in diameter. It is known as popolo kikania, or Apple of Sodom, Solanum linnaeanum. Both the kikania and the popolo kikania are reputed to be poisonous.
A photo of the popolo ku mai is shown on Page B1. For views of its native relatives, visit University of Hawai'i botany professor Gerald Carr's Web site at www.botany.hawaii.edu/faculty/carr/solanum.htm.
If you have an issue, question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate, The Advertiser's Kaua'i Bureau chief and its science and environment writer. Reach him via e-mail at jant@honoluluadvertiser.com, by telephone at (808) 245-3074, or by regular mail at P.O. Box 524, Lihu'e, HI 96766.
