June 1 - 3 , 1978 - University of Hawaii at Manoa

correlated with the amount and physical phase of the available
water, as well as the age of the rock on which they are growing.
Stereocaulon vulcani, the primary colonizer of most lava
flows in Hawal'i, characteristicallv - qrows - where the annual rainfall
is above 30 inches a year. Though one would expect to find
it at the summit which supposedly receives this amount of rain
each year, it is extremely rare and very poorly developed there.
Its near absence is probably because most of the rain comes in
two or three major kona storms each year. It is found throughout
the rest of the Crater District but below 6000 feet its distribution
is regulated by the growth of other organisms. The occurrence
of this species in any appreciable quantity below 6000 feet
is generally a good indication of the recent disturbance
community.
of the
Stereocaulon octomerellum grows on large boulders in the high
rainfall area of the eastern side of the Kaupo Gap. It is
normally found only on well-weathered, exposed rocks.
Stereocaulon ramulosum has an almost intermediate ecological
position between the above two species. It favours environments
in which cloud inundation is frequent. The height and fertility
of the plants is indicative of the frequency of the cloud cover,
the lower stature and infertile specimens indicating drier,
harsher conditions.
Litter Communities
Where plant litter accumulates and areas where the humus
content of the soil is high, the endemic Cladonia leiodea is dom-
inant. The species is not tolerant of shading so it is charac-
teristic of the open scrub communities. The luxuriance and
colony size of the plants are an indication of the moisture
regime of the area. The largest specimens are found in the
wetter areas. The plant is particularly sensitive to mechanical
disturbance and may serve as an indicator of past pig activity
when absent from an area in which it should logically appear.
A rather unusual litter community occurs under the dead but
still standing leaves between Descham sia clumps. All of the
species are very attenuated and none ___P_.
are ertlle which is probably
due to the suboptimal levels of light filtering down between
the leaves. Pseudocyphellaria crocata, ~ticta weigelii,
Peltigera golydactyla and Cladonia scabriuscula are the most
common svecles in this situation. I know of no similar communitv a
type adapted to such low light intensities.
Leaf Communities
In the gullies behind Paliku a fragmentary lichen community
is found on the leaves of Pelea. Two species are present and
represent the upper elevational limit of a specialized community
normally found below 1000 feet. Their occurrence in this highly