CORVALLIS, Ore. - While some plant species may have disappeared from Oregon in the last half century, other species are moving north, adding to the state's floral diversity.

Those are among the results reported by the Oregon Flora Project in a new book, the first comprehensive assessment of the state's native and naturalized plants since 1961.

"This book is for a broad audience," said Linda Hardison, project director and an assistant professor in the Oregon State Department of Botany and Plant Pathology. "The information has practical uses for so many people: ranchers, gardeners, landscapers, planners. We are always striving to make it useful for people."

For more than two decades, from the high desert to the Cascades and the Willamette Valley to coastal rain forests, botanists and citizens have assembled almost 600,000 observations of Oregon's diverse flora. Among the findings:

  •  Oregon is home to about 4,700 plant taxa (species, subspecies and varieties), making it the fifth most diverse state in the country, despite differences in area. This is 15 percent more than were recorded here in 1961.
  •  A total of 159 taxa collected prior to 1961 have not been documented since then.
  • Some plant species have moved into Oregon from Nevada and California, possibly reflecting the impacts of climate change.

Flora of Oregon: Volume 1: Pteridophytes, Gymnosperms, and Monocots, was published by the Botanical Research Institute of Texas. It can be ordered for $75 on the project website,

"Oregonians love their land and its natural resources," said Hardison. "Individuals statewide have contributed to make the book and our website a better resource." More than 1,000 volunteers shared photos, reviewed data and submitted lists of plants seen on hikes. Plants have also been included from studies by university researchers, the Native Plant Society of Oregon and state and federal agencies.

In addition to descriptions of grasses, sedges, lilies, ferns, and conifers, the volume includes a history of botanists in Oregon, color photos and descriptions of the state's 11 ecoregions and 50 mapped locations for exploring botanical sites. Artist John Myers contributed 86 new pen and ink drawings.

"Plants are the foundation of life on Earth, and correctly identifying plants can help us make good decisions," added Hardison, such as being aware of the presence of rare plants or invasive weeds. "With a new Flora, a rancher can recognize a new noxious weed that invades their property and, by controlling it, save their rangeland. This work is the basis for knowledge that touches every citizen of this state."

Volume 2 is due to be published in the fall of 2017 and volume 3 in late 2019.

In addition to individual donations, support was provided by the Bureau of Land Management, the Oregon Community Foundation and the Native Plant Society of Oregon.

Editors include Hardison, Stephen C. Meyers, Thea Jaster and Katie E. Mitchell. The book is dedicated to the memory of Scott Sundberg, an Oregon native, former Oregon State researcher and University of Oregon graduate who founded the Oregon Flora Project in 1994. Sundberg died in 2004.


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Linda Hardison, 541-737-4338