252 
PACIFIC SCIENCE, Vol. IV, July, 1950 
that winds of hurricane force sweeping across 
the Pacific in different directions at different 
periods of geologic time are responsible for 
this random deposition. Certainly tremen- 
dous variations in climate have existed since 
the origin of the islands sometime in the 
early Tertiary period. 
Speciation and distribution of the carices 
of Hawaii have not followed the usual pat- 
tern found in many island genera. There are 
only two narrow endemics — Carex kauaien- 
sis R. Krauss, which is limited to the bogs of 
Kauai, and Carex pluvia var. koolauensis R. 
Krauss, which is found in the central Koolau 
Range on Oahu. The other species occur on 
most of the islands, though certain ones are 
conspicuously missing on the more westerly 
islands. There are no records of Carex maclo- 
viana var. subfusca ( W. Boott) Kiikenth., 
Carex Svenonts Skottsb., or Carex Nealae R. 
Krauss on Oahu, Molokai, and Kauai. Hawaii 
and Maui, on the other hand, have every spe- 
cies and variety with the exception of Carex 
kauaiensis R. Krauss and Carex pluvia var. 
koolauensis R. Krauss. Carex Meyenii Nees, 
however, is the only species found on all the 
islands. The lack of local endemism is to be 
expected in a genus which fruits prolifically 
and is dispersed easily by air and water. Most 
of the species and varieties are able to survive 
on ridges as well as in ravines, so that geo- 
graphical isolation of minor mutations does 
not occur often enough to be a factor in the 
development of taxonomic entities. Never- 
theless, there appears to be some difficulty in 
achieving dispersal across the channels of 
water separating the islands. It is to be ex- 
pected that a complete distribution will be 
achieved naturally in the future inasmuch as 
suitable habitats exist on all the islands for 
almost all of the species. The range of Carex 
wahuensis var. rubiginosa R. Krauss, which 
is moving into the region occupied by variety 
Meyeri, by migration from east to west, illus- 
trates the path of such invasions although 
the habitat range for this species is consider- 
ably greater than that for some of the others. 
TAXONOMIC TREATMENT 
This section presents a key to and descrip- 
tions of the species of Carex found in the 
Hawaiian Islands. The key is based on char- 
acters found in the mature- fruited inflores- 
cence. The key may be followed using peri- 
gynia alone but, wherever feasible, additional 
characters of inflorescence and vegetative 
structure are included. The key is strictly an 
artificial one and no implications as to natu- 
ral relationship are to be drawn from it. The 
distribution of the species may be more read- 
ily perceived by reference to the maps. The 
citations of specimens examined are followed 
by letters designating the herbarium in which 
they are found. These abbreviations follow 
the system proposed by Lanjouw (1939: 
142). If no abbreviation is included, the 
specimens are in the Herbarium of the Ber- 
nice P. Bishop Museum, Honolulu, T. H. 
The abbreviations and the institutions in 
whose herbaria the specimens are deposited 
are as follows: 
C — Cornell University, Ithaca, New York 
GB — The Botanical Garden, Gothenburg, 
Sweden 
G — Conservatoire et Jardin Botanique, 
Geneva, Switzerland 
GH — Gray Herbarium, Harvard Univer- 
sity, Cambridge, Massachusetts 
K — Kew Botanical Gardens, England 
KY — University of Kyoto, Japan 
NY — New York Botanical Garden, New 
York 
P — Museum National d’Histoire Naturelle 
de Paris, France 
US — Smithsonian Institution, Washington, 
D. C 
TI — University of Tokyo, Japan 
The illustrations have been selected to 
show the range of variation within each spe- 
cies and variety. Three different specimens 
