FLORA OF HAWAIIAN ISLANDS HITCHCOCK. 459 



striking habit of most of these. The prevailing form is palmlike, a 

 slender trunk crowned with a cluster of narrow leaves. In some of 

 the larger species the trunk may be as much as 40 feet high. The 

 flowers are clustered at the base of the leaves or are borne in showy 

 racemes, and in many species are remarkably beautiful. 



To the botanist and layman alike, there is no group of plants that 

 presents more of interest than the ferns. They are everywhere from 

 desert to rain forest and from sea level to the upper limit of vegeta- 

 tion on the high mountains. In size they vary from the gigantic tree 

 fern to the minute epiphytic ferns less than an inch long. In some 

 regions they are so numerous in both species and individuals that they 

 impart the dominating aspect to the scene, and other plants appear 

 as individuals scattered among them. The ferns and their allies num- 

 ber about 185 species. As individuals the tree ferns are the most 

 conspicuous. They comprise 3 species belonging to the genus Ci- 

 botium. A common and widely distributed species is C. menziesii 

 in which the twice pinnate fronds are as much as 12 feet long and 5 

 feet broad, raised upon trunks usually only a few feet tall but some- 

 times as much as 30 feet (Rock). At the base of the leafstalk there 

 is a growth of soft yellowish wool called pulu by the Hawaiians and 

 used by them for stuffing pillows and mattresses. 



Contrasted with these giants are the pygmies in the form of nu- 

 merous species of epiphytes. In the rain forest the epiphytes, in- 

 cluding ferns, mosses, and lichens, cover every available trunk and 

 branch with a soggy coating dripping with moisture. Some of the 

 ferns creep over the surface by means of rootstocks; others are 

 tufted. In some of these epiphytic forms the fronds are narrow and 

 only an inch long with one or two fruit spots upon them. 



A common and, to the explorer, troublesome fern is a climbing 

 ( i species {Gleichenia dichotoma) with repeatedly forked steins. These 

 $ r trail over bushes and often form impenetrable thickets over large 

 areas. 



On lava flows on the upper slopes of the high mountains, extend- 

 ing to the upper limit of vegetation, is a tufted coriaceous species 

 {Polypodium pellutidum) about a foot high, with pinnatifid fronds. 

 In dry areas the lobes incurve until the tips touch over the upper 

 surface. Plants of this species may be found in holes in the lava as 

 the last outposts of vegetation on Mauna Loa. 



To the layman a description of the flora of the Hawaiian Islands 

 would be incomplete without a reference to the silver sword {Argy- 

 roxiphium sandwicense) . This rare and striking plant is found on 

 the cinder slopes in the crater of Haleakala and on upper slopes of 

 the high mountains of Hawaii. The form in the crater of Haleakala 

 is slightly different from that on Hawaii and has been distinguished 



