GUNNERA PETALOIDEA GAUD., A REMARKABLE PLANT 
OF THE HAWAIIAN ISLANDS 
Vaughan MacCaughey 
A distinctive- feature of the Hawaiian flora is the prevaiHng en- 
demicity of the rain-forest species. About 85 percent of the flowering 
plants of the islands are endemic, and the bulk of these are character- 
istic of the rain-forest zone. This zone lies between the elevations of 
2,000-6,000 ft. The mountains of Kauai, Oahu, East Molokai, 
West Maui, and the Kohala Range on Hawaii, rise to heights of 3,000- 
6,000 ft., and thus their summits are covered with dense rain-forest 
vegetation. The great valleys of erosion have eaten back into the 
very hearts of these mountain masses, so that the summit regions 
abound in knife-edged ridges and great precipices. Many of the 
summit ridges are only three or four feet wide at the crest; many of 
the precipices are 800-1,800 ft. high. The rainfall in these regions is 
torrential, and much of the vegetation is of the most pronounced 
hygrophytic type. 
One of the most characteristic and conspicuous plants of these 
humid summit regions is the endemic halorrhagaceous Gunnera 
petaloidea Gaud.^ In the little hanging valleys that abound in this 
zone, on the precipices as well as in the steep stream-beds, are masses 
of this titanic herbaceous-perennial. The gigantic leaf-blades are 
three to four feet in diameter, peltate on fleshy petioles two or more 
feet long.2 The petioles arise from a creeping or erect rhizome, which 
is fleshy, green, and four or five inches in diameter. The huge crown 
of leaves springs from the apex of the rhizome. As the latter is often 
branched, the total mass of foliage was spread over an area of ten or 
twenty square feet, with a height of six or eight feet. In places where 
they have not been disturbed by the landslides that are common in 
these regions, these gigantic herbs often cover areas fifty to a hundred 
feet long and twenty or more feet wide, as on the upper slopes of a 
precipice, where they form a beautiful mural tapestry. 
1 See bibliography. 
2 The blades of the Chilean G. manicata, the largest of the genus, are 5-10 ft. 
in diam., on petioles of 6-7 ft.; these are used in Chile for tanning hides. 
33 
