VERIFIED PLANTS OF SPECIAL CONCERN WITHIN THE COUNTIES 



ANNUAL BURSAGE 

 Ambro sia acanthicarpa 



CLASSIFICATION 



1. FAl-IILY: Asteraceae; Composite or Sunflower Family. This 

 family has the largest number of species in Montana, and is 

 subdivided into twelve v/ell-def ined tribes in most technical 

 keys. Annual bursage is a member of the Heliantheae Tribe, 



a large tribe distinguished by imperfect flowers, style 

 without a fringe of hairs, pappus never chaffy, and style 

 branches flattened, v;ithout stigmatic lines and commonly 

 with elongate, pointed hairy tips. 



2. GENUS: Ambrosia ; Ragweed genus. Some species in this genus 

 have notoreity in that their v;indborne pollen causes 



hayf ever . 



3. SPECIES: Annual bursage ( Ambrosia acanthicarpa ) . The 

 scientific species epithet refers to its spiny 



(Gr. acanthi-) fruits (Gr. -carpa) . 



PRESENT LEGAL OR OTHER FORKAL STATUS 



1. FEDERAL STATUS 



a. U.S. FISH AND WILDLIFE SERVICE: none 



b. BUREAU OF LAND MANAGEMENT: none 



2. STATE: In 1993, Annual bursage was added to the Montana 

 state species of special concern list since it was only 

 known from six collections in the state, and five of the six 

 were before 1940. It was given a state rank of "SU" (status 

 unknown) because it was also suggested by Dorn (1984) that 

 it may possibly be adventive. The appropriateness of 

 tracking it on the state list was re-evaluated in the course 

 of this study. The reason for its apparent rarity as 

 indicated by collection records is because it is restricted 

 to settings with reworked sand deposits, which are uncommon 

 in the state and have not been closely-studied. However, 

 this species increases under heavy grazing pressure and is 

 under no foreseeable threats. It is therefore re-assigned a 

 state rank of "S3S4" (vulnerable or potentially secure in 

 Montana) . 



10 



