(horizontal underground stems) . Ramets (branches 

 forming tufts of leaves at the soil surface) arise 

 from the rhizome. Each ramet persists for 1-3+ 

 years, produces a flower stem and then perishes. 

 Each year, new ramets are produced, some old 

 ramets persist in a vegetative state and some 

 ramets flower and perish. If ramets flower their 

 third year on average, then ca. 33% of all ramets 

 will be in flower on an average year. 



In 1997 only a small proportion (ca. 10%) of the 

 Carex parryana ssp. idahoa ramets observed had a 

 flowering stem. This distribution of vegetative 

 and fertile ramets suggests that ramets may remain 

 vegetative for 5-10 years before flowering, 

 assuming that 1997 was an average year. 



Carex parryana ssp. idahoa often occurs in 

 discrete colonies covering ca. 1-5 m^. Such 

 colonies may be a single genet. 



G. ECOLOGY 



1. BIOLOGICAL INTERACTIONS 



a. Competition and facilitation: Carex idahoa 



ssp. parryana occurs in dense turf of wetland 

 meadows. At 14 sites canopy cover of 

 graminoids was always high (60-100%) , while 

 canopy cover of forbs varied from low to 

 moderate (5-50%) (Appendix D) . There was no 

 correlation between the average height of the 

 vegetation and the abundance of C. parryana 

 ssp. idahoa at these sites (Appendix D) . 

 These observations suggest that C. parryana 

 ssp. idahoa is a late successional species 

 capable of persisting in a strongly 

 competitive environment. 



There were strong negative associations 

 between Carex parryana ssp. idahoa and Poa 

 pratensis, Antennaria microphylla and Aster 

 occidentalis (Appendix D) . These 

 correlations may indicate competitive 

 interactions, or they may be a response to 

 differential grazing histories among the 

 sites (see below) or both. The two forbs 

 that increased as C. parryana ssp. idahoa 

 decreased are smaller in stature and not 

 likely to cause competitive exclusion of the 

 rhizomatous sedge without herbivore pressure. 

 Poa pratensis is an aggressive, exotic, 



14 



