494 MacCauGHEY: THE STRAND FLORA 
reservation that not all strand plants are halophytes. The 
Hawaiian types to be considered may he referred to the litho- 
philous and psammophilous classes, as follows: 
A. LITHOPHILOUS 
Sheet or flow lava. 
Vertical rock shores or sea cliffs. 
Littoral creviced rocks. 
Lava boulder and pebble beaches. 
Tufa beaches. 
Coral limestone strands. 
2 ee 
B. PSAMMOPHILOUS 
Coral sand. 
Root molds. 
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1. Sheet or flow lava.—This type of strand is of first impor- 
tance in the Hawaiian group, both quantitatively and from the 
standpoint of ecologic history. There are more miles of lava 
beach than of any other type, or of all the other types combined. 
The relatively large areas and recent formation of Maui and 
Hawaii have caused this to be the dominant type. Historically 
it is first to appear, and it eventually gives way to strands of other 
types. The lava flows may be either relatively recent and un- 
eroded, like many on the island of Hawaii, or they may be of ex- 
treme antiquity and deeply carved, like those of the Na Pali 
coast of Kauai, or Kaena and Makapuu, on Oahu. The beach 
itself, in either case, is formed of exposed lava beds, very rocky, 
with practically no sand or soil, and distinctly uncongenial to 
plant life. Lava sheet beaches occur on all the larger islands, but 
are best exhibited on the shores of Hawaii and East Maui. Every 
gradation may be found from very low, flat lava strands, only a 
few feet above sea-level, to bare sea precipices 600-700 feet in 
height. 
From the historic standpoint the lava beach is of twofold sig- 
nificance. If of recent flow material—e. g., the Hawaii flows of 
, and the exposure of a new littoral 
