^'- 40 



TAXON: TrisetuBi orthochaetum A. S. Hitchc. 



COMMON NAME: None 



FAMILY : Poaceae 



STATU S : ENDANGERED 



Ha±>itat: in a boggy meadow 



Distribution: Known only from the type locality at Lolo Hot Springs, 

 Bitterroot Mts., Missoula Co., Montana. 



Nature of EIndcingerment: This elusive grass has been sought in vain over 

 several years by Dr. C. L. Hitchcock, by Dr. L. H. Harvey and by myself. 

 Dr. Harvey has on occasion tciXen agrostology classes to the type locality 

 in search of T. orthochaetum . In 1951, Dr. Harvey found a single plant 

 at this site which resembles the species. Similar plants have not since 

 been collected. I have spent 30 hours over the past three years searching 

 this area with negative results. The type locality has been altered 

 drastically since the t£ocon was originally collected (in 1908) . Where 

 once there was a boggy meadow, there is now a paved highway, a swimming 

 pool, parking lots, a bar, and a campground. The habitat and the species 

 may have been extirpated as a result of construction. 



Trisetum orthochaetum is thought to be a hybrid between T. wolfii and 

 T. canescens due to its intermediate morphology and apparent sterility 

 (i.e., the type specimen has abortive amthers) . However, the hybrid ori- 

 gin has never been confirmed. During my field studies, the putative 

 parents were found in an intermixed population along the margins of a 



