North-Central U.S.A.

North-Central U.S.A. is the American Midwest and northern Plains, grouped into one TDWG region covering roughly 2.13 million square kilometres. It includes Ohio, Indiana, Michigan, Illinois, Wisconsin, Minnesota, Iowa, Missouri, Kansas, Nebraska, North Dakota, and South Dakota. Climate is temperate throughout — humid continental in the north and east, drier and more continental on the Plains, and edging into humid subtropical along the Missouri–Kansas border.

Most of the region is flat to gently rolling, shaped by ice and rivers. Glaciers reworked the northern half during the last ice age, leaving moraines, drumlins, and the thousands of lakes that define Minnesota and Wisconsin. The Mississippi and Missouri river systems drain almost the entire region. Two upland exceptions break the pattern: the Ozark Plateau in Missouri, and the Black Hills of South Dakota, where Black Elk Peak rises to 2,207 metres.

Vegetation falls into three broad belts. The eastern third was historically deciduous forest — oak-hickory in the south, beech-maple in the Great Lakes states, mixed with sugar maple, basswood, and eastern hemlock further north. The central third is tallgrass prairie, dominated by big bluestem (Andropogon gerardii), Indian grass (Sorghastrum nutans), and switchgrass, with rich forb diversity — Echinacea, Liatris, Silphium, Asclepias. The Plains states grade westward into mixed-grass and finally shortgrass prairie. Wetlands punctuate everything: prairie pothole complexes in the Dakotas, Great Lakes marshes, and bottomland hardwood forests along the major rivers.

The Ozarks support an unusually rich woodland flora with a number of regional endemics. Spring ephemerals — Sanguinaria canadensis (bloodroot), Trillium grandiflorum, Dicentra cucullaria — carpet eastern deciduous forest floors for a few weeks each year before the tree canopy closes.

The Verdarium catalogue currently has fifteen species tagged here: thirteen circumboreal mosses (Hylocomium splendens, Dicranum scoparium, Polytrichum formosum, and others) plus two semi-aquatic plants, Hydrocotyle verticillata and Spirodela polyrhiza. None are signature prairie or eastern woodland species.

The region holds some of the country's most important botanical institutions — the Missouri Botanical Garden in St. Louis is one of the world's leading plant research centres, joined by the Chicago Botanic Garden and the Morton Arboretum further north.