Phytolith types and type-frequencies in native and introduced species of the sagebrush steppe and pinyon-juniper woodlands of the Great Basin, USA

This study catalogued phytolith morphotypes and production of common native and introduced flora from two primary plant community types in the Great Basin Desert region of the USA - sagebrush steppe and pinyon-juniper woodlands. The reference collection for this study included 143 species from 40 plant families, including 68 introduced and 75 native plants. We examined 96 forbs, 33 grasses, sedges and rushes as well as 14 trees and shrubs. The phytolith morphotypes of more than 100 of these species were previously not described. We found that about 51% of the plants produced none or only trace amounts of phytoliths, while the remaining 49% had common to abundant production. All the grass species produced abundant phytoliths. Morphotype and frequency of phytolith production differed between native and introduced grass species. At least half of the forbs had common phytolith production and most generated the common dicotyledon morphotypes such as silicified epidermal cells and hairs. Several morphotypes in native and introduced forbs were unique for the genus and species within the reference collection. There was very little phytolith production in the woody species we examined. We found no identifiable phytolith assemblage for pinyon-juniper woodlands in the Great Basin. These results will be useful for future research regarding historical ecology, palaeoecology, palaeoclimatology and ethnobotany. (C) 2009 Elsevier B.V. All rights reserved.