1917] MACCAUGHEY—HAWAIIAN FLORA 391 
Maui is a volcanic doublet made up of two masses of widely 
different ages. Haleakala probably ceased activity at about the 
same time as Mauna Kea. The windward, northern face of 
Haleakala, like that of all the Hawaiian mountains, receives 
torrential rainfall (400 inches per annum) and is densely covered 
with jungle forest. The leeward, southeastern slopes are conspicu- 
ously arid and barren. In its geological and botanical aspects 
Haleakala is much more closely related to Kea and Loa on Hawaii 
Pe 
Fic. 5.—Manana or Rabbit Island, deeply eroded tufa cone, isolated as small 
barren islet off windward coast of Oahu, near Maka-pu’u Point; about 2200 ft. long 
and 400 ft. high, separated from main island by channel of 1 7 vegetation sparse 
and stunted, no arborescent vegetation. 
than to its associate West Maui. It is separated from Hawaii 
by a relatively narrow channel, 26 miles wide and 1032 fathoms 
deep. From the standpoint of this paper it will be considered as 
one of the Kea, Loa, Hualalai family. 
THE FOUR GREAT MOUNTAIN MASSES.—These four great volcanic 
mountains, Haleakala, Kea, Loa, and Hualalai, closely resemble 
each other in a number of important ecological particulars: (1) their 
summits rise 8000-14,000 ft. above sea level and are frequently 
covered with snow; (2) there is a large treeless zone on the summit 
of each; this is most extensive on Loa, Kea stands next, then 
