Organization of the collection
Our holdings of seed plants are organized following the Dalla Torre and Harms system at the family level, alphabetically by genus within families, and alphabetically by species within genera. Ferns and fern allies are shelved alphabetically by genus.
Within species, specimens are grouped in color-coded folders by region, as follows:
Yellow - Arizona
Pink - United States (excluding Arizona), Canada & Greenland
Green - Mexico and the remainder of the Americas, including Caribbean Islands
Brown - Old World
White - Cultivate specimens, regardless of region
Exceptions are noted prominently at the appropriate locations in the herbarium.
In addition to the regular collection, types are stored separately, as is the boxed collection of large fruits and cones. There is also a collection of seeds, and small holdings of bryophytes and lichens.