The Hawaiian flora, occurring as it does on the most remote large land mass on earth, in extremely diverse terrain and climates, has a high proportion of endemic plants upward of 88 percent of flowering plant species and 76 percent of ferns and fern allies. Yet this array derives from an estimated 256 to 280 individual species arriving and diversifying over the 70million years of the archipelago’s existence. About 80 percent of native species can be traced to IndoMalayan origins, 18 percent to American origins, and 2 percent to Austral origins. Currently, a huge number of the native species are rare, threatened, or endangered. Slide after slide showed individuals from the last known populations of their species in the wild, some numbering in the double and single digits.

The means by which those pioneer ancestor species’ seeds and spores arrived include attaching to birds’ feet and feathers, embedding in mud on birds’ feet, and importation in their digestive tract. In addition, winds likely carried very light propagules, such as seeds of the ancestor of ‘Ohi’a lehua, Metrosideros polymorpha offered by Don Mahoney in the plant drawing this night, and spores of various ferns to Hawaii; salt-tolerant, buoyant seeds, like those of Wiliwili, Erythrina sandwicensis, probably floated by sea.

Gustafson showed slides from the five major plant zones: coastal, lowland forest, montane forest, subalpine and alpine. Mo’omomi, on the northwest coast of Moloka’i, is an extensive intact dune area where Sesbania tomentosa, a showy low pea shrub with reddish flowers, grows. Populations with different color forms grow or grew on most of the major islands. Chamaesyce roxburgii, a euphorbiaceous shrub, is one species in a diverse genus under pressure. Many of the coasta-lzone plants are adaptable for cultivation and are being used in new landscaping on Waikiki, for example. The greatest number of indigenous species those known to be also native to Hawaii and beyond are found in the coastal zone. Vitex rotundifolia, a plant that has been available at Cal Hort drawings, is one.

Lowland forest species Gustafson found in the Pu’u Wa’awa area of the Big Island in the 1980s include Caesalpinia kavaiensis, an ornamental tree with bipinnate foliage, Kokia dryanarioides, a Hibiscuslike tree with ruby-red flowers adapted for pollination by endemic honeycreeper finches, and a tree violet, Isodendron, known from only one cinder cone and vulnerable to fire. In other lowland forests grew Gardenia brighamii, a treelike gardenia now limited to one wild specimen on Moloka’i.

The lobelioids, genera allied to Lobelia, have proliferated in the copiously wet, ferny, montane forests of the Islands. Gustafson showed many of the unusual shrubs and trees and their tubular, bisymmetrical flowers, each adapted to specific bird pollinators now endangered or extinct due to predation by introduced mammals and birds. Perhaps the most spectacular was Lobelia wahiawaensis, with profuse four-foot spikes of creamy greenish flowers on a low shrub. He noted a few species, like Cyanea grimesiana, that had gone extinct in the wild since he had photographed them.

Subalpines occur only on Maui and Hawai’i, the Big Island, where volcanoes rise to 10,000 and over 13,000 feet, respectively. One potential ornamental for cool-summer parts of the Bay Area may be Mamane, Sophora chrysophylla, a tree found on the slopes of Mauna Kea along with the local variant of cosmopolitan Dodonea viscosa. Higher up on the sometimes snowcovered Mauna Kea, as well as on Haleakala, the volcano on Maui, is the famed silversword known to the Hawaiians as Ahinahina, Argyroxiphium sandwicense, descended from the tarweeds Madia, etc. of California. Each of the two alpine peaks has its own subspecies, and other peaks, like Pu’u Kukui in West Maui, have their own species and other genera in the alliance, such as Dubautia.

From beachside to high peaks, Robert Gustafson provided a tour of the plants that he had studies and photographed, often at great personal peril and discomfort, and gave the audience a sense of the delicate, subtle beauty of the original, besieged flora of Hawaii. He completed his talk with a gorgeous assortment of slides of rare exotic tropical ornamentals being cultivated in botanic and private gardens on the populated islands.

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