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.
PLANT NOTES
THE FERNS. The Sliding Sands Trail drops from White Hill on bare slopes of red and gray Cinders. As it levels below Puu o Pele, a lush, green carpet spreads along the south wall of the crater. It is a surprise to discover that ferns compose the verdure, for several kinds find the shelter of the cliffs agreeable. Haleakala’s KA’UPU, Polystichum haleakalense Brack., a rather coarse, low plant with scaly stems, grows among the shrubs. The pellucid polypody, ’AE, Polypodium pellucidum Kaulf., and the maidenhair spleenwort, ’IWA’IWA, Asplenium adiantum-nigrum L., grow here, but they are common elsewhere as well. Iwaiwa is a small plant with shiny, slender stems and stiff, triangular fronds that thrives in the brush. On Leleiwi Pali it is a tiny thing, clinging to the rocks. This fern is known in mountainous regions in many countries. Another maidenhair spleenwort, ’OWALI’I, Asplenium trichomanes L., makes its home on barren lava above 5,000 feet on the inner slopes of the crater. Its small, opposite, rounded or ovate frond segments, pinnae, grow on wiry stems that form dense clumps. Look for it along Halemauu Trail on Leleiwi Pali. It is found in the temperate zones and on high mountains in many parts of the world.
Bracken, KILAU, Pteridium aquilinum var. decompositum (Gaud.) Tryon, a stiff cosmopolitan, is among the best-known ferns. It grows in grassy spots inside and outside the crater. Foraging pigs, seeking its tasty rootstocks, often uproot it in the forests. The young leaves of AMA’UMA’U, Sadleria cyatheoides Kaulf., add a touch of red along Halemauu Trail on Leleiwi Pali. At Paliku, several moisture-loving ferns grow on logs, rocks, and moss-covered trees. Large, dense ae are quite unlike the frail specimens on Leleiwi Pali. The following can be seen in damp spots and on tree trunks: Maui’s paddle, ’EKAHA, Elaphoglossum reticulatum (Kaulf.) Gaud., with paddle-shaped blades 6-12 inches long; ’EKAHA-’AKOLEA, Pleopeltis thunbergiana Kaulf., a small fern with tough, pale, elliptico-oblong (paddle-shaped) fronds; and MOA, Psilotum complanatum Sw., belonging to a small group of tropical plants, PSILOTALES, which reproduce by spores, but are distinct from true ferns, clubmosses, and the better-known orders.
Swordfern, NI’ANI’AU or ’OKUPUKUPU, Nephrolepis exaltata (L.) Schott., is widely distributed at Haleakala as it is elsewhere in Hawaii. Cliffbrake, KALAMOHO LAULI’I, Pellaea ternifolia (Cav.) Link, grows among rocks in dry, sunny locations at higher elevations above the park entrance and inside the crater. It is common. The bluish-green pinnae of this short, slender fern grow on opposite sides of the dark, wiry stems. They are cleft into three linear segments.
THE NATIVE GRASSES. Several native grasses grow above the park entrance: Trisetum glomeratum (Kunth) Trin., Deschampsia australis forma haleakalensis Skottsb., and Agrostis sandwicensis Hillebr. The Trisetum, also common inside the crater, is called mountain pili, PILI being the lowland grass known in many tropical regions and used for thatching houses in Hawaii. The Hawaiian name for T. glomeratum is PILIUKA, upland pili. In some places it is also called HE’U PUEO, the hoot of an owl.
All three grasses are tufted, i.e., bunch grasses. The Deschampsia has tough, wiry blades (leaves) with shiny, open panicles of flowers and seeds. The Agrostis has stiffly upright blades and culms (jointed stems) with spike-like panicles. The pili has flat blades usually covered with soft hairs. The panicles are contracted or spike-like.
THE SEDGES. [Fig. 1]. Sedges are generally grasslike wind-pollinated herbs that grow in tufts or bunches. They are often the dominant plants in cold marshes, especially in the Arctic. They have little economic value and grazing animals find them unpalatable. Some have tough, pliable stems that are woven into mats and baskets; some have fruiting spikes that are attractive in dry bouquets. Most have 3-angled stems around which the blades are ranked. The inconspicuous, green flowers are crowded in tight, flattened spikes, often grouped on top of a slender, grasslike stem. Hawaii has a dozen or more native genera with many of its species widespread in the world.
The species common on the upper slopes of Haleakala and on the crater floor, Gahnia gaudichaudii Steud., bears shiny, ebony fruits. These can dangle, suspended by the wilted, threadlike stamens for more than a year from the fruiting stalk. Another sedge, Carex macloviana subfusca (W. Boott) Kukenth., grows in clumps along the south wall. The fruiting stalks bear cylindrical or ovoid clusters of 4-9 spikelets, each ½-1 inch long. This sedge grows from Lapland and Greenland to northern South America, but in Hawaii it has been found only on Haleakala and Kohala Mountains above 4,000 feet. The Hawaiian variety was first described from a specimen collected at Lake Tahoe, California. The interesting Oreobolus furcatus H. Mann, mentioned as occurring on West Maui, also grows in Koolau Gap.
RUSH, Luzula hawaiiensis (O. Ktze.) Buch. A visitor brought me a small tufted plant with grass-like leaves covered with soft, silky hairs. He was all excited, believing he had found a young silversword on the cinder flats near the summit of Mt. Hualalai. The plant was the endemic rush that lives in wet places above 3,000 feet in the mountains of Maui, Hawaii, and Kauai. In Haleakala Crater, I found it on Leleiwi Pali and near Paliku, where others might mistake it for an immature silversword or greensword. The Hawaiian general name for grasses, sedges, and rushes is MAU’U.