54 BOTANICAL GAZETTE [JANUARY 
The slope of most the valleys is so steep, and the drainage basin 
so restricted, that the run off is extremely rapid, and the fluctuations 
in stream volume are very pronounced. The upper course of the 
stream, through the rain forest, is littered with large lava boulders, 
dotted with small pools, and interrupted by numerous cascades. 
The waterfalls vary in height from a few feet to 1500 ft. These 
mountain streams, owing to their intermittent nature, are not very 
favorable for the algae, and luxuriant growth is rare. The con- 
trast between the abundant algal flora of a flooded taro loi or rice 
field, on the warm lowlands, and the paucity of forms inhabiting 
a cold, intermittent mountain stream, is very striking. On the 
other hand, although the algae are not abundant, they are present 
in moderate quantities and in considerable diversity. 
On the moist earth along the banks of the stream, on the rocks 
in the bed itself, and in the frequent pools one finds such algae as 
Gleocapsa quaternata, A phanothece Naegeli, Phormidium, Lyngbya, 
Anabaena, Scytonema rivulare, Tolypothrix distorta, Dactylococcus 
infustonum, Dictyosphaerium pulchellum, Raphidium polymorphum, 
Pediastrum, Conferva, Ulothrix, Stigeoclonium, Draparnaldia macro- 
cladia, Oedogonium, Bulbochaete, Cladophora nitida, Nitella haviensts, 
Xenococcus Kerneri, Characium groenlandicum, Closteriopsis longis- 
sima, Schroederia setigera, Salpinocoeca minuta, Dinobryon sertu- 
aria, Hemidinium nasatum, Asterionella formosa, Triploceros, 
Melosira, Cyclotella, Cymatopleura, etc. The faces of the water- 
falls, and the dripping cliffs immediately adjacent, are the habitats 
of such forms as Gloeocapsa magma, Oscillatoria spp., Spirulina 
major, Nostoc spp., Scytonema varium, etc. 
Hot springs and thermal waters 
The only waters in the Hawaiian Archipelago that have tempera- 
tures higher than that of the atmosphere are those in the vicinity 
of the active volcano Kilauea, Hawaii. There are a number of 
warm pools and springs in the Puna district, and these evidently all 
receive their heat from the subterranean molten lavas of Kilauea. 
The temperatures of these waters vary between 30 and 35° C. 
These warm pools contain a luxuriant algal growth, especially in the 
form of a coating over the rocks that form the sides and floors of 
the pools. Representative thermal species are Fischerella thermalis, 
