Yosemite National Park, world-famous for its majestic granite cliffs and thundering waterfalls, is also a region of great appeal to the admirer and student of wildflowers. Many casual visitors are aware of only a few of the more showy species such as redbud, dogwood, azalea and lupine, but interested observation will disclose a fascinating array of flowering plants, seemingly endless in their variety of form, color and life habits. When one’s interest and attention are drawn to this facet of Yosemite’s splendor, it becomes a continuing source of delight and inspiration, increasingly so with each visit.

The great diversity in Yosemite’s flora is chiefly a product of the pronounced altitudinal variations within the Park. On the western edge, near the El Portal entrance, the elevation is only 2,000 feet above sea level, within the Digger Pine-Chaparral Belt of the foothills. (Under the former Merriam system of life zone classification, this would be known as the Upper Sonoran Zone.) By contrast, the Sierra crest which marks the eastern boundary of the Park includes peaks reaching to heights of 12,000 to 13,000 feet, the so-called Alpine Zone. Between these two extremes are gradually increasing elevation zones which contain basins, canyons and mountain slopes, yielding wide contrasts in climate and soil conditions and thereby producing an amazing variety of plant forms.

One of the interesting concepts of plant occurrence in Yosemite is the sequence of wildflower blooming. This extremely pleasant aspect of the floral year is particularly associated in our minds with the season of springtime, when all the world of nature arouses itself from winter dormancy and begins its primary task of producing seeds and fruits—preceded, of course, by the beautiful phenomenon of multi-hued blossoms. Spring, according to the calendar, normally may be expected during the months of April and May, with the increasing warmth of June, July and August generally bringing an end to the period of bloom. Not so, however, in Yosemite National Park.

In this favored region, spring puts in its first appearance in early March (sometimes even in late February) with the earliest buttercups pushing through the greening turf of the Sierra foothills. As week follows week across the calendar, spring strolls in footsteps of beauty up the mountain slopes, stopping in a grassy meadow, then beside musical streams of icy melt-water, pausing to decorate a canyon’s walls or to add vibrant colors to a lakeshore. As spring passes, each succeeding altitudinal zone of the Park comes alive with its own varieties of flowers. Finally, at the end of August, the pageant of springtime reaches its last act with the flowering of the gentians across the subalpine meadows while rock-fringe and alpine columbine bloom among the rocky fastnesses of the summit peaks. A blessed land is this, indeed, where one is privileged to enjoy six months of springtime, through the simple expedient of following the season vertically through the Park!

The purpose of this book is to provide a trail guide to these flowers of Yosemite, especially the ones most likely to attract attention. Within the confines of this small volume it was not possible to be more inclusive; over 1,500 classified flowering plants, shrubs and trees occur within Yosemite National Park. I will try to point out representative trails and roads where you may follow the ascending passage of spring. The book will attempt to list the most showy flowers in these areas and to suggest when and where they may be seen. Descriptions of the flowers have been phrased in nontechnical terms, emphasizing the salient characteristics of color, form, size and location which will enable the layman to make a ready identification. But for further use in studying these plants and their related taxonomic classifications, the scientific names have been included with the common names used in the Yosemite area. Mary Curry Tresidder was one who knew and loved the wildflowers of Yosemite, with a deep sensitivity born of a lifetime spent in the Park. Though every other aspect of Yosemite was familiar to her as well—its trees, its birds, its waterfalls, its trails and its incredible scenery—the wildflowers remained her chief joy and constant inspiration. She understood their characteristics, knew where to find them and when to expect them, and felt ever at home among the flowered canyons and meadows of this part of the Sierra Nevada.

For many years she had considered writing a book on Yosemite wildflowers, hoping to communicate to others some of her own feeling for their unique charm, while assisting the interested beginner to learn more about them. Though she kept careful diaries and field records, the years slipped by and the book was never started. As she neared the end of her life, realizing she would never achieve this cherished goal personally, she decided to make provision in her will for the work to be accomplished.

This book is the direct result of her vision and generosity, reflecting a lifetime of interest in Yosemite wildflowers. Much of its material is based on her journals, diaries and articles she prepared occasionally for publication in newspapers and magazines. Additional field work has been done by the author along the trails and roads of the Park during many years of residence in Yosemite. I am deeply indebted to Dr. Carl Sharsmith, noted Yosemite Ranger-Naturalist, Emeritus Professor of Botany at San Jose State University, San Jose, California, and an outstanding authority on the flora of Yosemite, for checking the work for scientific accuracy.

Dana C. Morgenson

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