Agronomy and Horticulture Department


Date of this Version



Published in American Journal of Botany, Vol. 29, No. 5 (May, 1942), pp. 366-372. Copyright 1942 Botanical Society of America. Used by permission.


Many profound changes in mid-continental grasslands have resulted from the recent extended drought. In the prairies of eastern Nebraska, Kansas and South Dakota, the earlier continuous stands of bluestem (Andropogon scoparius and A. furcatus) have often been greatly fragmented and now occur as relict patches a few square feet to many square rods in extent. Loss of approximately 95 per cent of little bluestem has left the prairie cover very open. Over large areas, except for weeds and a few surviving grasses and forbs, the soil was bared (Weaver, Stoddart and Noll, 1935; Weaver and Albertson, 1939). Grasses more xerophytic than the bluestems have greatly increased, notably needle grass (Stipa spartea), prairie dropseed (Sporobolus heterolepis) and western wheat grass (Agropyron smithii). The wheat grass has entirely replaced other grasses in many prairies and is such a vigorous competitor for water that its invasion into countless relict areas of weakened bluestems has gradually resulted in their disappearance together with most of the accompanying forbs.