HAWAII NATURE NOTES
THE PUBLICATION OF THE
NATURALIST DIVISION, HAWAII NATIONAL PARK
AND THE HAWAII NATURAL HISTORY ASSOCIATION

HALEAKALA PLANTS

Haleakala rises above the belt of warm trade winds into the cold, dry climate of the Alpine Zone. Temperatures at night may drop below freezing even in the warmer part of the year; the growing season is short and life is severe. The sparse plants that can live here crouch closely to the ground, diffusing or forming compact rosettes. All they have in which to grow are porous rocks and loose cinders that cannot hold moisture, lack organic matter, and do not yield a firm base for rooting. Species extending to lower elevations are here depauperate from wind and cold, although elsewhere they may attain a sturdy stature, even tree-size. Few seedlings are seen; individuals whose life span has finished remain conspicuous in death. Neither trees nor mats of shrubs are seen, but mosses and lichens find this Alpine desert to their liking. Oddly enough, one looks in vain for brilliant blossoms, such as one has come to expect in the high Sierra and the Rockies. The summit is a biological island on an oceanic island which, geological evidence indicates, never was part of a continent. The Hawaiian Chain was never near land of appreciable height and size.

How the Alpine plants came to Hawaii is uncertain since they have descended from ancestors so remote that past relationships are vague. The great Swedish botanist, Carl Skottsberg, believes that they are derived from a flora that grew on summits higher than any that exist today. Such assumption adds to the problem, as little else leads one to believe that elevations ever significantly exceeded 14,000 feet, i.e., the highest that exist today. In a report for the Fifth International Botanical Congress (Proceedings, pp. 91-97, Cambridge, 1931), Skottsberg listed 13 species found exclusively in the Alpine Zone, all of which are endemic, native to no other place than Hawaii's highest volcanoes. Three other species listed as occurring in the Alpine Zone extend their range downward into the next lower Subalpine Zone, for which he has listed a total of 23 species, 20 of which he labels endemic. These adjoining zones are not sharply delimited, but blend into each other at 9,000 feet.

As elevation decreases and conditions for growth become better, the number of plant species increases. The Subalpine Zone with lower limits just above the park entrance has some of the most interesting plants found in the islands. Trees are absent but some of its shrubs extend their range to lower elevations and grow big, sometimes even to tree-size. Most Subalpine plants have small leaves or leaflets, indicating that lasting moisture is still scant. Occasional snowfall seldom remains long and never piles into drifts, which would conserve moisture.

Most of the interior of the crater is bare or thinly covered with vegetation. The uncongenial climate of the summit spills into it and extends throughout its length, though the elevation is much lower. Extensive aa flows, ash, and cinder cones cover the floor. Yet the crater has perhaps become best known through the presence of one of its plants, the silversword. Also, the lips of Koolau and Kaupo Gaps are botanically distinctive in contrast to the barreness elsewhere. This results from the fog and rain that sweep through them in late morning, only to dissolve upon mixing with the warmer air inside. As the day progresses, clouds push further and further inward, until, rarely, the whole depression may become filled. Koolau especially is a treasure-trove for the plant-lover. Below 6,000 feet, quite outside the park, it becomes impenetrable jungle surpassed only by that in Kipahulu Valley, a few miles east. Kaupo Gap is comparatively dry, but it supports a sparse scrub cover of great interest. The lower parts of Kaupo Valley are grazing land. Paliku is the only place within the park in which vegetation is lush. As it climbs Leleiwi Pali, Halemauu Trail is bordered by OHELO and ferns, among them AMAU MAU which is pleasing to the weary hiker's eye.

In the northwestern angle of the park not far from the inn, Nianiau Crater has had a renowned floral character and history. Today it is overgrazed and drab. Dr. Joseph Rock, Hawaii's famed dendrologist, discovered a curious tree lobelia, Clermontia haleakalensis, growing within it. He happily described the plant as "antediluvian in appearance." This most primitive member of a distinctive Hawaiian floral group had a robust trunk from which clumsy, stubby branches shot off, each crowned with a feather-duster of long, thick, strap-shaped leaves like some pompous dictator's headdress. MAMANE and AKALA grew thickly around it; rarer associates included tree geraniums, Neurophyllodes sp., with flowers like violets, tree Railliardia, shrubby Hawaiian buttercups, and greensword, Argyroxiphium virescens, that is threatened with extermination by grazing to an extent greater than of its relative, the silversword.

Clermontia Haleakalensis (BISHOP MUSEUM, J. F. ROCK COLLECTION).

Even though they are outside the park, some plant communities on the outer slopes of the mountain should be mentioned, because they are related to park forms and carry a compelling interest. The trail from Olinda to Waikamoi is through a transition forest between the wet and the dry that once drew botanists from many parts of the globe. It is now overgrown with foreign weeds, so that native shrubs survive only here and there. The mountain forests above Olinda have all been destroyed and are replaced by plants from faraway lands.

Although it now lies devastated by change, one of the richest botanical regions in Hawaii comprises the forbidding lava fields of Auwahi on the southwest slope of Haleakala. Fifty species of native trees once thrived in its fabulous mixed forests. The only known specimen of Maui hibiscadelphus, H. wilderianus, a relative of the hibiscus, was found here. It had a curved corolla that opened only slightly at the top. Its congener, H. giffardianus, once equally rare, still survives in Kipuka Puaulu at Kilauea, where a few vigorous plants, started by air-layering, receive tender care from the National Park. The last known Maui specimen of MAHOE, Alectryon macrococcus, grows in an Auwahi gulch. This tree has large double fruits (mahoe means twins) that split open to expose a shiny, chestnut-brown seed clasped in a brilliant scarlet aril. The ALANI, Pelea multiflora, of the lava fields is festooned with a lichen, Usnea australis, that appears to prefer it to all other trees. Haleakala sandalwood, Santalum haleakalae, with attractive red flowers grows to be a tree 25 feet tall. Other famous native trees include 'OHE'OHE, Tetraplasandra kauaiensis; OHE, Tetraplasandra meiandra; A'E, Fagara sp., 'ALA'A, Planchonella auahiensis, with golden fruits; HO'AWA, Pittosporum terminalioides; OLOPUA, Nestegis sandwicensis; A'IA'I, Pseudomorus sandwicensis; MEHANE, Antidesma pulvinatum; and KAUILA, Alphitonia ponderosa, whose hard and durable timber was used in sacred structures.

Many unusual plants occur in the steep valleys to the north and east outside the park. Since the dense jungles in which they grow are inaccessible except to hardiest botanists, they are seldom seen. Here grow 'APE'APE, Gunnera petaloidea, a plant with geranium-like leaves three or more feet in diameter; a delicate, rare, native begonia, Hillebrandia sandwicensis; several exquisitely flowering lobelias. The summit bogs on Kukui and Mt. Eke in West Maui have a curious, distinctive flora that includes three species with origins ascribed to the Antarctic: Orebolus furcatus, a sedge; Acaena exigua of the Rose Family; and Lagenophora maniensis, a composite.

Tetramalopium (BISHOP MUSEUM, J. F. ROCK COLLECTION).

Begonia (BISHOP MUSEUM, J. F. ROCK COLLECTION).

The Haleakala road is the easiest way to reach elevations above 7,000 feet in Hawaii. The lower mountain slopes up which it winds were once clothed with fern jungles that yielded with altitude to dry forest. All is now altered. Extensive grasslands and eucalyptus groves today leave the lasting impression on the visitor. Even on the heights, cattle, goats, introduced plants, insects, and other agents have wrought permanent change. Rare and interesting forms of native life have been exterminated or are well on the way to extinction. The National Park is trying hard to save what is left of the native cover within its boundaries and to restore the former scene wherever it is possible to do so.

Plants of the distinctive Haleakala environment show differences, some slight, some considerable, from close relatives elsewhere. Examples are the OLAPA at Paliku, the silversword, and the KUPAOA. The differences have been fashioned by combinations of factors. The unstable, permeable ash and cinders have scant soil and little available mineral matter. They cannot hold water nor do they yield secure anchorage. The effects of winds, isolation, exposure, and nature of terrain are reflected by the distorted shapes. Silversword, Artemisia, Bidens, and many other plants well show adaptation to peculiar environment. Why are some species found nowhere else? How did the plants get here in the first place and how have they changed with the passing of time? What has been the impact of exotics? What use did the Hawaiians make of the plants? To the hurried and casual visitor, the flora of Haleakala may appear drab and uninteresting. With better acquaintance, it becomes a stimulating study indeed.

'Ape'ape (BISHOP MUSEUM, J. F. ROCK COLLECTION).