Welcome to the NPWRC Herbarium

The Northern Prairie Wildlife Research Center's herbarium was established in the 1960's to house reference and voucher specimens of plants for researchers in wetland and waterfowl ecology in the northern Great Plains. Since then, specimens from many other areas of the United States and Canada have been added to the collection. In 1978, the Herbarium (code NPWRC) was listed in the International Index Herbariorum to facilitate inter-herbarium loans and exchanges.

Today, the NPWRC herbarium houses over 6,000 plant specimens. All specimens in the collection are in a searchable database that can be accessed from this page. For more information on the NPWRC Herbarium, please contact the collection's manager using the “Contact Us” form found on this page.

Featured Plant - Hymenoxys richardsonii

Plant Image

Only western North Dakota is home to the Colorado rubber plant. Except for one record in Divide County, all collections of this species have been south and west of the Missouri River. Elsewhere, the plant occurs south along the east side of the Rocky Mountains from Saskatchewan to Texas west to Utah and Arizona at elevations up to 10,000 ft.

North Dakota specimens of Colorado rubber plant are about 4 inches tall. Plants are perennial, and tufted from a branching woody structure (caudex) atop a rather thin taproot. The thread-like leaves are branched, lie below the flower heads, and are covered with tiny resin glands. Mature plants usually have about 5-20 stems that each have 1-5 yellow flower heads about 3/4-inch wide. Fruits are tiny achenes about 1/8-inch long.

Look for Colorado rubber plant from June to August on dry soils in hilly areas. Grazing seems to have little effect on the plant's abundance. These "rubber plants" probably were so called because the Amerindians of New Mexico made chewing gum from the bark and roots.

Colorado rubber plant is a member of the sunflower family (Asteraceae) of which there are about 15,000 species worldwide and about 200 species in North Dakota. The generic name was compounded from the Greek humen "membrane" and oxys "sour", likely in allusion to the translucent scales at the base of the flowers and the sour or bitter taste of several of the species. Theodore Cockerell (1866-1948) published the first acceptable scientific description of the plant in 1904, long after its discovery by Sir William Jackson Hooker (1785-1865), who named the species in honor of the famous Scottish biologist and arctic explorer Sir John Richardson (1787-1865). Professor Cockerell was an intrepid student of the natural history of Colorado and New Mexico.

Author Credit:

"Plant of the Week" comes from a series of articles about native wildflowers of the North Dakota grasslands written by NPWRC biologist Harold A. Kantrud. The articles appeared weekly in local newspapers. Each article is three to four paragraphs in length and usually consists of the life history of the species, its identifying traits, where in North Dakota one can expect to find it, and its nomenclatural history. Kurt A. Adolfson and Jack Lefor provided the many excellent photographs used in the original articles and this resource.