25 



difficulties in building roads through them, 

 and b.) their lack of timber. However, 

 harvesting on the slopes directly adjacent 

 to the sites would be likely to adversely 

 impact them. 



B. Overut i 1 izat ion for commercial* sporting* 

 scientific* or educational purposes: No 



significant past or existing threats known. It 

 is possible that overco 1 lee t ing for scientific 

 specimens could impact the existence of this 

 taxon, if additional locations are not discovered. 



C. Disease or predation: The only observed insect 

 pests were aphids on many of the inflorescences 

 at the Granite Creek South site. The meadows and 

 adjacent woods along Granite Creek are impacted 

 by heavy moose trampling in some areas, but 

 direct impacts on the Tr i setum clusters was not 

 observed - 



D. Inadequacy of existing regulatory mechanisms: 



None known. 



E. Other natural or manmade factors. 



1. Past threats: Not known. 



S. Existing threats: The currently known 

 number of individuals of Tr isetum 

 orthochaetum is very low, and the taxon is 

 thus presently threatened by virtue of its 

 scarcity. However, more extensive surveys of 

 similar habitats throughout the Pacific 

 Northwest may yield additional stations. 



3. Potential threats: No additional threats 

 are presently anticipated. 



II. ASSESSMENT AND RECOMMENDATIONS 



12. General assessment of vigor, trends, and status: On 



the basis of current knowledge gained during this 

 study, Tr isetum orthochaetum is a very rare taxon, 

 restricted to an extremely small geographic area. 

 Evidence reviewed above suggests, however, that the 

 taxon is a sporadically produced, virtually sterile, 

 interspecific hybrid between T. canescens and T. 

 wo If i i . The taxon does not appear to be in imminent 

 danger of extinction at this time, and more extensive 

 surveys may locate additional sites. However, further 

 biosystemat ic research remains the first priority, in 

 order to identify the correct taxonomic status of 

 Tr isetum orthochaetum. 



