1917] MACCAUGHEY—HAWAIIAN FLORA 393 
Haleakala, and lastly Hualalai, the smallest of the four mountains; 
(3) the summits are marked by volcanic vents; either an active 
crater (Loa); or an extinct caldera (Haleakala); or great numbers 
of cinder cones (Kea); or by innumerable pit craters and cinder 
cones (Hualalai); all of these are large and tangible evidences of 
the earth forces by means of which the mountains were built up 
to their present height; (4) the mountains rise directly and gradu- 
ally from the sea, without intervening lowlands or plateaus; (5) the 
—Cinder cones on floor of Haleakala caldera; at extreme upper left are 
some eae sword plants (Argyroxiphium sandwicensis var. macrocephalum). 
slopes and flanks of each mountain are covered by thick blankets 
of lava, cinders, and ash, which in the arid summit and leeward 
regions have undergone little or no erosion; (6) each mountain 
has a lower windward region which receives heavy precipitation; 
this rain, amounting to several hundred inches per annum in many 
localities, has caused the rapid decay of the lava flows in these 
zones and has covered the flows with luxuriant rain forest; the 
original flow structure is obliterated beneath heavy beds of 
soil and vegetation. This paper does not include the humid 
areas, 
