k 
* 
The Vegetation 
The vegetation of Hihoa is dominated by a lov herbaceous cover comprised 
of the followings Sida fallax , Chenopodium oahuense , and Panicum torridum . 
Solanum nelsoni and Euphorbia celastroides are important members of this 
vegetation type. At the time of our visit (September, 1964-) the island was 
very dry and the common grass Eragrostis variabilis did not appear as 
plentiful as previous reports on the vegetation of the island would indicate. 
This grass is probably a seasonal dominant after the rainy season. The 
Euphorbia appears to prefer exposed volcanic rock sites, ho leaves were 
present on the plants observed in 1964. 
Portulaca caumii was common in the soil pockets of crevices on the 
middle and upper slopes. Portulaca lutea was dry on the lower and middle 
slopes and not obviously abundant in these areas while on the flat area 
near Miller 1 s Peak which receives more precipitation the plants were plump 
and in flower, 
Pumex giganteus was found on the north cliff face near the top of Tanager 
Peak. Collections of lichens were made and determinations of these are 
being made by various collaborators. The Hurnex was sterile at this time. 
Panicum torridum was most conspicuous on the upper slopes. Sesbania 
tomentosa and Tribulus cistoides were found on the south side of the cliffs 
on the upper slopes - the plants flattened and very dry. Most of these 
herbs shed much of their leaves during the dry season. 
Pritchardia remota, endemic to hihoa Island, is found in the dry 
stream beds and middle slopes of the east and west canyons and on the east 
upper slope of East Palm Canyon and on the upper west side of West Palm 
Canyon. A count of the Pritchardia revealed the following numbers: 
a) West Palm Canyon: 107 seedlings, 148 non-flowering and fruiting trees, 
127 flowering and fruiting trees; b) East Palm Canyon: 32 seedlings, 
69 non-flowering and fruiting trees, 46 flowering and fruiting trees. 
The following plant associations were observed: a) on rocky upper 
slopes with thin soils: Euphorbia - Chenopodium - Sida - Solanum ; Panicum 
- Portulaca ; Eragrostis - Sida - Chenopodium ; bj middle and lower slopes 
with deeper soils, some formerly held by terraces: Chenopodium - Sida - 
Eragrostis; Euphorbia on volcanic rock ridges; c) wet north face cliffs 
with soil pockets or bare rock: lichens; Panicum - Pumex - Portulaca lutea ; 
on middle and upper slopes in soil pockets: Portulaca caumii ; wet west 
and south face cliffs, thin soil on bare rocks: Chenopodium - Portulaca ; 
dry lichens; stream beds and sheltered cliff bases: Pritchardia ; Chenopodium 
- Sida - Solanum . At the base of West palm Valley is a sand beach which 
shifts prbbably on a seasonal basis. Heliotropium was collected from this 
site in 1964. Boerhavia diffusa was collected from this site in 1923. Wo 
evidence of Tetragonia or Schiedea was found in 1964. Both were very local 
in distribution in 1923 (Christophersen and Caum, 1931)* Twenty-seven 
plants of Heliotropium were counted, mainly on the slopes above the beach. 
