586 
VAUGHAN MACCAUGHEY 
conspicuously wind beaten. The heads of the valleys in the Punaluu 
region support a much finer type of forest than that of Manoa, for the 
former region has been practically free from the ravages of wild goats 
and other herbivores, and the forest is in its primitive condition. 
The Manoa Valley head occupies an ecologic position somewhat 
intermediate between the extremely arid and depleted valleys toward 
Makapuu Point, and the hygrophytic valleys of the central part of 
the range. 
13. PU'U PUEO (PUPIA) 
The upper floor is bifurcated by a ridge which emanates from the 
main summit ridge and which terminates in a green grassy hill known 
as Puu Pueo, the Owl Hill. This median ridge is about 2 miles long, 
its lowest point is 300 feet above sea-level, and Puu Pueo rises 500 feet 
above the valley floor. Due to the extensive erosion in the region 
mountainward of the hill, the ridge is conspicuously saddle-shaped, 
when viewed from the side. 
Puu Pueo was at one time, like the region immediately adjacent 
to it, densely covered with the mantle of the lower forest; the ravages 
of wild goats and cattle, wood-cutters, and in recent times, dairy 
cattle, have stripped from the hill practically all of its forest growth. 
The principal plant now is the ubiquitous Paspalum conjugatum; other 
plants occurring here and there upon the hill are Scaevola Chamis- 
soniana, Acacia Koa, Microlepia strigosa, Cordyline terminalis, Cler- 
montia macrocarpa, Pipturus alhidus, Sadleria Hillehrandii, Osteomeles 
anthyllidifolia, etc. 
This ridge originally extended down the valley much further than 
it does at present. It is not unlikely that there were other ridges 
lying parallel with it, and that the physiography was considerably 
more complex than that of Manoa today. The present broad floor 
may be the result of the almost total elimination of several of these 
ancient ridges. Under this hypothesis the plant life of the valley 
under these early conditions was probably more diversified and 
precinctive than it is at present. Erosion has caused an infinitely 
gradual shifting of plant groups and zones. Projecting this vision 
into the future, the head of the valley will become increasingly larger, 
all contours more regular, and the life conditions more mesophytic. 
Puu Pueo will have vanished and the foothills will have been com- 
pletely isolated as outliers, with low open gaps into Nuuanu and 
