Dixon publishes book on regional plants


hobart dixon

Dr. Hobart "Hobey" Dixon, Adams State University emeritus professor of biology, has published an identification guide to the plants of the San Luis Basin. Written for professionals and serious amateur botanists the book identifies ferns, conifers, and flowering plants of the San Luis Valley, the Taos Plateau, and surrounding mountains.

Including more than 1,200 plants, the book identifies plant species and includes English and Spanish common names. Familiar words and Latinized terms are used and a glossary defines the technical terms. A few diagrams illustrate diagnostic characters of some difficult families, but there are no pictures.

The guide is a "key" consisting of a series of either/or choices called couplets. At each couplet one picks the best of two choices which then leads to another couplet which, in turn, leads to others until the name of the plant is revealed. A key to conifers might begin:
1a. Needles in clusters . . . . . . . . . . . . . . .Pines
1b. Needles single. . . . . . . . . . . . . . . . . . . . . .2
2a. Needles square, stiff . . . . . . . . . . . Spruces
2b. Needles flat, soft. . . . . . . . . . . . . . . . . . . .3 etc..

Trained as a plant ecologist, Dixon was frustrated when he came to the Valley in the late 1960s because there was no reliable guide to the local flora. During the 35 years he taught at Adams State he used free time to work on the key, but most of the work was done after his retirement in 2001. Writing the key was "like creating a computer program and it was an intriguing challenge."

For the most part Dixon used plant specimens for the comparisons, but relied on some descriptions in professional publications when a specimen was not available. "Writing the key was fun, but proof reading 150 pages of either/or choices was the worst tedium," Dixon said.

The plants included in the book are those collected from the Basin, most of which are archived in the ASU herbarium. Under Dixon's guidance this plant collection grew from a few hundred to about 8000 specimens that were collected in southern Colorado and northern New Mexico.

Plants in the herbarium were collected by Dixon and botany students who had outdoor state and federal summer jobs and were able to collect in areas often not accessible to the general public.

Each plant specimen in the herbarium is pressed and dried, glued on a sheet of special paper, and labeled with complete collection information. Credit is given to collectors whose specimens are in the herbarium. Other herbaria report Basin plants that are not in the Adams State collection.

Dixon and his wife, Ruth, spent many hours in the mountains collecting and photographing wildflowers. He has done plant surveys with the Park Service, Forest Service, BLM, and the Colorado Division of Parks and Wildlife. Most recently he spent much of a summer on the Baca National Wildlife Refuge where he enjoyed quiet that included the sounds of coyotes, birds, toads, and mosquitoes.

An earlier edition of the guide was used by field workers who identified and classified vegetation at Great Sand Dunes. These workers helped in proof reading the 150 page guide. Fred Bunch, Resource Management Specialist at Great Sand Dunes and Adams State alumnus '77, was instrumental in the publication of the book.

The next project, in partnership with Ruth, will be a photographic guide to common local wildflowers in the San Luis Valley. "It will be written for the casual botanist rather than the professional field worker," Dixon said.

Currently "Vascular plants of the San Luis Basin, Colorado and New Mexico" is available at the Colorado Native Plant Society, the Narrow Gauge News Stand in Alamosa, or from the author at pixies@amigo.net.