MAMANE, Sophora chrysophylla Salisb. [Fig. 4.] A common native shrub or small tree of the Bean Family both inside and outside the crater up to tree line. It is recognized by more or less downy, narrow, compound leaves, racemes of yellow flowers, and twisted pods that have four wings and are constricted between the seeds. Goats eat it greedily and quickly exterminate it in an area. The hard, durable wood was used by Hawaiians in many ways; today it is a principal firewood for the crater cabins. A tree in full bloom is a beautiful object. The height of the flowering season is mid-spring.
GERANIUM, NOHOANU, HINAHINA. Fig. [6], [7]. Neurophyllodes tridens (Hillebr.) Degener & Greenwell is common above the park entrance and on the south wall within the crater. It sometimes becomes three feet tall and is readily identified by its silvery leaves, each of which has three small teeth on the end. The white flowers have purplish veins especially toward their centers. The blooming season is July to October. The silvery aspect of the plant, like the silversword, is imparted by a mesh of fine white hair that reflects the light of a passing car as effectively as the glass-beaded paint of directional signs.
Two native geranium relatives grow in Koolau Gap, N. ovatifolium (A. Gray) Degener & Greenwell and its variety superbum. The latter is common on the trail to Waikau not far from the foot of Leleiwi Pali.
One of the common plants growing on the crater floor is the exotic pink-flowered G. carolinianum var. australi (Benth.) Fosberg whose pointed fruiting bodies give it the common name, cranesbill.
HAWAIIAN HOLLY, KAWA’U, Ilex anomala Hook and Arn. The forest growing on the talus behind the Paliku cabins is the finest within the crater. A striking tree of this association is the Hawaiian holly that has dark, shiny, oval leaves with conspicuous networks of slightly depressed veins that make identification easy. Dense panicles of small, white flowers are followed by shiny, black drupes, like Christmas holly “berries.” The genus is that of the English holly. Curiously, the scientific name has been locally corrupted to ileck.
OLOMEA, Perrottetia sandwicensis A. Gray. A native shrub or small tree belonging to the same family as the bittersweet of the continent. The numerous tiny, round, red fruits, borne in panicles, suggest the relationship. The bright red venation of leaves and petioles make the plant easily recognized. I know of no plants within the park, but found many trees a thousand feet below the park boundary in Keanae Valley.
A’AL’II, Dodonaea eriocarpa Smith. [Fig. 8.] This is a common shrub in several varieties along the highway and in the western end of the crater. At Paliku and Kaupo Gap it becomes a tree up to 20 feet high and 8 inches in diameter. Its flowers are inconspicuous but clusters of dry, reddish fruit-capsules contrast, flower-like, with the surrounding green foliage. The fruits, abundant from July to September, are used for leis and dry bouquets. The hard brown heartwood was used for spears, pololu, daggers, pahoa, and other implements.
BEGONIA—PUAMAKANUI, Hillebrandia sandwicensis Oliv. (See illustration [p. 53].) The only native begonia, found in wet ravines often by waterfalls. It grows profusely at Koolau a mile below Holua Cabin at the foot of the rain-drenched pali. This succulent herb has a tuberous rhizome, unbranched, slender stems, and hairy, toothed leaves 4-10 inches in diameter. From June to August it bears sprays of bright, pink and white flowers. This is one of the floral treasures of Hawaii.
TARWEED. Cuphea carthagenensis (Jacq.) McBride. A low, sticky, hairy perennial from tropical America widely spread at lower elevations in the park. It has red or green branches, small ovate leaves, and tiny but not unattractive pink flowers ¼ inch across. Plants in rock crevices on cliffs are tiny; on the crater floor, they may become a foot high and form a dense shrubby mat over a sizeable area. The plant belongs to the LYTHRACEAE or Crepe Myrtle Family.
’OHI’A LEHUA, Metrosideros collina (Forst.) A. Gray. [Fig. 9.] This, the commonest tree in the islands, consists of a swarm of hybrids of which the parentage is still unknown. It is scattered within the park to tree line. It is abundant in the eastern end of the crater and at Paliku. The beautiful flowers, mostly red, a few yellow, may appear throughout the year. Here spring seems to be the best season for them.