396 The American Naturalist. [May, 
shrouded in carbonate of lime, the growing tips alone project- 
ing out of the stony mass. In ferruginous and in siliceous 
waters the mineral matter of the waters obscures and hides the 
vegetable filaments. Unfortunately, those who have studied 
the flora of hot springs have rarely published sufficient detail 
concerning the habitat of the species described to enable one 
to follow up this interesting feature of the subject, while the 
algae have been studied rather from a systematic than a broad 
biological standpoint. 
In reviewing the literature bearing upon the subject, I 
have found that vegetable life is a common accompaniment of 
thermal springs, and as widely distributed as the springs 
themselves. At the noted warm springs of Carlsbad, where 
the algous life has been studied by several botanists, there is a 
great variety of species, but the limiting temperature appears 
to be 130^ Fahr.' 
Sir William Hooker^ and Baring Gould' both mention the 
occurrence of crimson algae in the hot geyser waters of Ice- 
land, and Hochstetter' and other writers' describe slimy con- 
fervoid plants lining the bottoms of hot pools and streams in 
New Zealand, the highest temperature at which such growths 
have been observed being 153'' Fahr. 
In the hot springs of the Azores, Mosely found alga; grow- 
ing in water whose temperature was between 149*^ Fahr. and 
156*^ Fahr., and on areas splashed by almost boiling water. 
At the volcano of Camiguin no vegetation was found until the 
water had cooled down to 113.5^ Fahr.' In the Himalayan 
hot springs Dr. Hooker found a luxuriant growth of Lepto- 
thrix at leS^Fahr. and below.' Several other references were 
.433- Spencer. Tram 
1 Hooker. Vol. : 
Journal of J 
I Tour in 
Iceh 
md. V 
Iceland: I 
ts Scenes and 
Sagas. 
Reise der Oe Frigat. 
:No' 
Skey. Tra 
ns. N. Z. 
Inst 
;. Vol. 
XV., p. 302. 
Journ. Lin, 
1. Soc. 1 
;Bota 
iny.) A 
Himalayan 
Travels. 
Jos 
. Daltoi 
