ROLE OF SEDGES IN COLORADO PLANT COMMUNITIES 
129 
be somewhat different from the present hydrarch meadow, the characters 
of which depend largely on local edaphic conditions. Just what the cli- 
matic alpine meadow will be toward which both the xerarch and hydrarch 
series necessarily tend is not now quite apparent. For a long time to come 
the Carex elynoides grassland will be found just where it now exists. It is 
of a more permanent character, because more mesophytic, than the com- 
munities dominated by Carex stenophylla, C. rossii, and C. siccata. 
Carex in Various Xerophytic Associations 
Less important xerophytic Carices may be listed without extended 
comment. C. heliophila (pennsylvanica of western authors) is frequent in 
the mixed grassland of mesas and foothills, extending occasionally to the 
montane zone. Other species found at moderate elevations, none of them 
of common occurrence, are Carex brevior, C. occidentalism C. xera^itica, C. 
douglasii. In the montane zone Carex oreocharis is somewhat abundant 
and C. obtusata rather occasional in dry grassland of parks; C. geyeri occurs 
in dry forest openings. At high altitudes Carex phaeocephala and C. pyre- 
naica are frequent species of dry rocky slopes. C. perglobosa is occasional 
on alpine ridges. 
List of Species of Carex'^ 
In the following list the species of Carex are arranged in three groups ac- 
cording to the "soil moisture index" employed by the writer (6). It need 
hardly be stated that species may sometimes be found outside their accus- 
tomed habitats. 
(a) Species in water or wet soil (marsh plants), the soil moisture index 
8, 9, or 10: aquatilis, aurea, canescens, capillaris, chalciolepis, disperma, 
halleri, illota, lanuginosa, lasiocarpa, nehraskensis , nelsonii, nigricans, pau- 
percula, phaeocephala, rostrata, scopulorum, stipata, tenuirostris, vesicaria. 
{b) Species in meadow or other mesophytic situations, the soil moisture 
index 6 to 7 or sometimes 5 : albonigra, bella, ebenea, festivella, illota, nova, 
pachystachya, praegracilis, praticola. 
(c) Species in xerophytic situations, the soil moisture index typically 4 
but varying to 5 or 3 : brevior, douglasii, elynoides, geyeri, heliophila, obtusata, 
occiderttalis , oreocharis, perglobosa, phaeocephala, pyrenaica, rossii, siccata, 
stenophylla, xerantica. 
Summary 
The foregoing paper deals with the part played by sedges in the plant 
communities of northern Colorado. It is based upon studies in all the life 
2 This is not a complete list of the Carices of northern Colorado but includes only the 
species mentioned in this paper. Most of the author's collections were originally identi- 
fied by Dr. Theodor Holm, but recently the specimens have been gone over again by Ken- 
neth K. Mackenzie, Esq. Thanks are due to both these gentlemen for their courtesy and 
painstaking care. 
