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166 LENNART FRIDENand pointed out its probable importance for thedispersal of the heath flora.The early agriculture was a kind of shifting cultivationon dry, loose soils that may have attractedStipa. Thus the name of "field wool" (akerull)earlier applied to Stipa by the rural population,may indicate a very old age indeed (FRIDEN 1951,p. 421), for Stipa never grows on arable fieldsof the modern type.It is of course impossible to prove when Stipaand its companions reached our area. The indicationsin favour of a relic theory are stronger forthe alvar flora (ALBERTSON 1946a, B. M. P. LARS­SON 1959 b, p. 209, Du RIETZ 1959c, pp. 219-220)than for the steppe plants, although an early immigrationhas considerable support.THE PRESENT STATE.-Despite dissimilar distributionpictures in different species, the Stipa communityhas a homogeneous character. With orwithout Stipa, the association has a firm footholdin the calcareous Central Vestrogothian area (FRI­DEN 1959 a, pp. 239-242, with map and table).The fruiting of the feathergrass varies greatlyfrom year to year. After the hot and dry summerof 1959, the fruiting in next summer was unusuallyplentiful (about 1000 culms in the Nas locality).During sequences of cool or rainy summers, thefertility declines, but this perennial warmth-demandinggrass is able to endure for long periods ina reduced, ' vegetative state.The three localities of surviving Stipa are protectedby law, and it is ·satisfactory that severalowners have with great alacrity consented to theprotection of additional stretches of eskers in theNas and Asaka kame area. However, the decreasein grazing and the consequent increase in developmentof brushwood and juniper scrub is a problem,and for a successful long-time management bothclearing and moderate grazing seem indispensable.Even today, agriculture may unintentionallydamage the remaining strongholds of the association,either directly or indirectly, through dust containingfertilizers, herbicides, etc., applied to theadjacent fields. Despite these unsolved problemsof management, there is good hope that the peculiar,colourful vegetation of the steppic dry meadows,possibly of great antiquity, will be preserved fortimes to come.Acta Phytogeog1·. Suec. 50