INTRODUCTION 



In recent times, there has been a rapid increase in public awareness of 

 the need for understanding and maintaining the diversity of life on earth. 

 This concern has prompted private organizations and governmental agencies to 

 include biological diversity issues in their planning and activities. The 

 purpose of this volume is to provide current information on the rarer elements 

 of the flora of Montana, enabling interested parties to include assessments of 

 sensitive plants in their work. 



In 1984, the Montana Rare Plant Project published Vascular Plants of 

 Limited Distribution in Montana . Since that time, there have been many 

 advances in our knowledge of the flora of the state. Many species formerly 

 thought to be rare have been found to be more common, while other species 

 previously not known from Montana have been found here. Establishment of the 

 Montana Natural Heritage Program in 1985, with its data organization and 

 acquisition procedures, has also contributed to our knowledge of the state's 

 flora. Consequently, a need to update the available information regarding the 

 rare plants of Montana arose; this volume represents an updated synthesis of 

 this information. 



The Montana Natural Heritage Program is a computer-assisted inventory of 

 the geographical locations of rare plants, animals, and plant communities in 

 the state. The database also contains information on the size and condition 

 of each species occurrence. Computer searches for occurrences in particular 

 geographic areas, or for particular species, can be conducted. To request 

 such information, the program may be contacted at the following address: 

 Montana Natural Heritage Program, State Library, 1515 E. 6th Avenue, Helena, 

 MT 59620; phone 406/444-3009. 



Information on the status of rare species is dynamic, and subject to 

 change as further studies and documentation accumulate. New information 

 regarding locations for the plant taxa listed in this volume can be submitted 

 to the MTNHP, for entry into the database. Any comments or recommendations 

 for status changes, additions, or deletions from these lists can also be sent 

 to the above address. 



NOMENCLATURE 



In most cases, nomenclature follows Hitchcock and Cronquist (1973) and 

 Great Plains Flora Association (1986). References for some taxa must be 

 sought in the recent taxonomic literature; these are cited where necessary. 

 Synonyms are given only when we feel they may be in common usage. Common 

 names are taken largely from Hitchcock and Cronquist (1973). 



STATUS CLASSIFICATIONS USED IN THIS MANUAL 



MONTANA STATUS 



We reviewed all species previously listed as rare, threatened, 

 endangered, or undetermined by Lesica et al. (1984), as well as many others, 

 including recently described species, those recently discovered within the 

 state's boundaries, and those nominated for consideration. We placed all 

 reviewed species in one of the following eight categories based on the 

 perceived degree of threat to the continued existence of the plant in the 

 state. There are no state laws that provide any direct, substantive 

 protection for rare plants in Montana; thus, these categories are currently 



