Ask Mr. Smarty Plants

Here is a list of guides that I happen to own and use when I visit the area.  These are all very useful and also easy to use.  The first three include grasses, but I don't know of a grass ID book specific to the Northwest coast; however, there is always Hitchcock's Manual of Grasses in the United States.

Plants of the Pacific Northwest Coast by Jim Pojar and Andy MacKinnon

"A field guide to 794 species of trees, shrubs, wildflowers, aquatics, grasses, ferns, mosses, and lichens with color plates, line drawings, distribution maps and easy-to-use keys.  There are also notes on ethnobotanical uses of plants, unique characteristics and name origins."

A Field Guide to the Common Wetland Plants of Western Washington & Northwestern Oregon, Sarah Spear Cooke, editor

"This is part of the Seattle Audubon Society Trailside Series. From the description on the book cover: More than 300 species, including trees, shrubs, herbs, grasses, sedges, rushes, and ferns. Common and scientific names, cross-referenced in the index. Synonyms and US Fish and Wildlife Service wetland indicator status. Descriptions emphasizing characteristics most useful for identification. Detailed habitat and range information with icons indicating habitat preference at a glance. Illustrated with color photographs and line drawings. Modern and traditional ethnobotanical uses of many species."

Plants of Western Oregon, Washington & British Columbia by Eugene N. Kozloff

"Too large to be considered a field guide, but an excellent resource for plant identification with extensive, easy-to-use keys. It has description of more than 2500 native and non-native introduced and naturalized species with 700 color photographs and 350 line drawings."

Wildflowers of the Pacific Northwest by Mark Turner & Phyllis Gustafson

"Featuring more than 1240 stunning color photographs, this comprehensive field guide will remain a trusted, authoritative trailside reference for years to come. It describes and illustrates 1220 commonly encountered species, both native and nonnative, including perennials, annuals, and shrubs. Encompassing the Pacific Northwest from southern British Columbia to northern California, from the coast to the mountains and high desert, this handy book is perfect for hikers, naturalists, native plant enthusiasts, and anyone wishing to learn about the amazingly diverse wildflowers of the region. Organized by flower color and shape, and including a range map for each flower described, it is as user-friendly as it is informative. (From Amazon.com)"

Wildflowers of Washington by C. P. Lyons

"From Amazon.com From seashore to mountain peak, the wild, untended blossoms of Washington flourish throughout the growing season. This easy-to-use guide by the late Chess Lyons is loaded with brilliant color photographs and complete descriptions of nearly 500 species."

"From Amazon.com With over 400 species, exquisite detail, full true-color photographs, this guidebook is the best wildflower guide for Washington, Oregon, Idaho, western Montana, Northwest Wyoming, British Columbia, and western Alberta. Don't make your next trip without it. Updated version, April 2004."

Northwestern Wild Berries by J. E. Underhill

"From the book cover: Wild Berries contains a simple key and nearly 100magnificent color photographs to guide you quickly to berry identification.  Additional notes on how early Indians valued berries and where and when to collect them make this book an indispensable tool."

Here are some web resources:

From the US Geological Service (USGS)—Western Wetland Flora: Field Office Guide to Plant Species

Washington Native Plant Society has a photo gallery of native plants of Washington.

Native Grasses of the Pacific and Northwest from Gardening-for-Wildlife.com has descriptions and some photos of native grasses.

Native Plants: Identifying, Propagating & Landscaping from Washington State University Extension.

Native Plant Resources for the Pacific Northwest from the Water and Land Resources Division of King County, Washington.

Puzzled by Poaceae?--A Grass Identification Workshop are notes from a workshop at the Washington State University State Weed Conference.