Oklahoma Natural Heritage Inventory
This website is provided by the Oklahoma Biological Survey to aid persons interested in the study and identification of the woody plants of Oklahoma. The information provided was developed with both the academic and amateur in mind. It is our hope that in doing so a broader audience will come to appreciate the richness and variety of the Oklahoma flora. There are approximately 2,400 plant species in Oklahoma (Taylor and Taylor 1994) and about 330 are trees, shrubs, or woody vines.
For the purpose of this document, a woody plant is defined as a plant that retains some living woody material at or above ground level through the non-growing season (several species of small cacti fit this definition, but are not recognized trees or shrubs). Categorizing a woody plant as "tree", "shrub", or "vine" is often difficult and can appear arbitrary. Distinguishing between a tree and a shrub can be particularly difficult. That is why it is not unusual to see descriptions such as "small tree or large shrub." In this treatment we have adopted the following definitions: a tree is a woody plant that is at least 10 cm (4 in ) in diameter at 1.4 m (4.5 ft) above ground level; a shrub is less than 10 cm in diameter at 1.4 m above the ground and usually has multiple stems or is clonal; a woody vine does not stand upright without support but climbs on other vegetation or sprawls on the ground.
We hope that the format we have adopted will both aid in identification and enrich general knowledge of woody plant species. Each entry starts with the species' Latin binomial or scientific name, followed by the family name and a short list of synonyms (e.g., older scientific names that are no longer in use) . This information was acquired from a variety of sources, but the Natural Resources Conservation Service list was used extensively. Also included is the common name, or names, for each species. The most prevalent common name heads the list. Some common names are quite descriptive and can actually aid in plant identification (i.e., moonseed vine, rough leaved-dogwood, skunkbush). Others give clues to medicinal and other uses (i.e., toothache tree, whorehouse tea, soapweed). Others seem whimsical and rather entertaining (supple-jack, sow-teat blackberry, ladies' eardrops).
Following the species name is a set of descriptions of the physical characters of the plant. This is the primary vehicle for plant identification. To facilitate identification, photographs (all of which are taken by the authors unless noted otherwise) are inserted throughout the description section. Unfortunately, photographs are not available for all woody plant species at this time. The description of each species includes information regarding bark (color, pattern, etc.), twigs (size, leaf scars, bud morphology), leaves (size, shape, placement), flowers (size, color, number of petals, etc.) and fruit (size, shape, color). Currently, there are no dichotomous keys available for the woody flora on this website. We hope to redress this matter in the near future.
Knowledge of the habitat preferences and distribution of a species is another important identification aid. Therefore, we have provided a succinct description of each species' associated habitat. Information regarding a species' geographic distribution is provided in a written synopsis listing state and regional distribution. A county dot map accompanies each entry to illustrate the distribution within the state. The dot maps were derived from herbarium specimens housed at the Bebb Herbarium, at the University of Oklahoma, the Oklahoma State University herbarium, the University of Science and Arts of Oklahoma, and the University of Tulsa. Label data, including county of collection, directions to collection site, collector, and year of collection, were recorded into an electronic database. We are continuing to database specimens from other regional schools (i.e., University of Tulsa, Southeastern Oklahoma State University, Cameron University, Northwestern Oklahoma State University and Northeastern State University) and institutions beyond our borders (i.e., the Botanical Research Institute of Texas, the University of Kansas).
Distribution maps are not only an effective tool for the study of species ranges, but also focus floristic survey and inventory activities. For example, as a result of this mapping exercise, we have identified several Oklahoma counties with inadequate representation in herbarium collections. These gaps in our knowledge can affect how we interpret distribution maps. Therefore, we have engaged in an systematic collection program in those "under represented" counties. As a result of these activities, the distribution maps for some species will be updated annually.
Finally, we included some general comments, notes regarding the etymology of scientific names, tips for field identification and distinguishing species with similar appearance, medicinal uses, horticultural uses, wildlife uses, and Regional Wetland Indicator (RWI) status. (RWI information will be of most interest to specialists in wetland issues. The indicator status species changes from time-to-time, so we encourage interested individuals to visit the USDA plants database for the most current designation.)
We hope that you find this website useful for the study of Oklahoma woody plants. We would like to emphasize, however, that this is a work in progress. Updates will be made regularly. Forthcoming features include dichotomus keys for identification, additional photographs, and updated distribution maps for all of the native and naturalized woody plants found in Oklahoma.