A Comparison of Mycetozoa Fauna in Sandstone and Limestone Regions of Augusta County, Virginia

Abstract

Collecting the Mycetozoa in southeastern Augusta County has disclosed a number of unusual forms, and has revealed that the types of genera present in one region compared to another vary according to the lime content of the soil. This investigation is the first ecological study of the Mycetozoa in relation to their lime requirement. Forms have been secured from two general localities: one situated in a sandstone region near the base of the Blue Ridge Mountains, the other in a limestone region well out in the Shenandoah Valley. The forms in the sandstone region select habitats on old logs and sphagnum moss which is scattered around the numerous ponds that appear there. Numerous springs feed into these ponds which are formed as a result of limestone sinks. However, there is no outcropping of limestone in the present area as it is completely covered by overthrusting and many feet of talus and wash at the foot of the Blue Ridge. Therefore, the limy material that lies many feet below the sandstone wash is unavailable to the use of the lime genera of the Mycetozoa. The ponds usually present a gradual incline on the sides, and are well hidden in the flat woods. The numerous springs near these ponds form boggy shallows on the edges, affording excellent pockets in which leaves and other vegetable materials collect. In the process of decay these materials hold much moisture. All of these factors are favorable to the growth of the Mycetozoa. Many of the more familiar species of the Mycetozoa are present here. Didymiiumn nigripes var. xanthopus Lister grows in abundance on sphagnum moss. Lam proderma arcyrionema Rost., Comatricha typhoides Rost., Arcyria denudata Wettstein, A. cinerea Pers., A. digitata Rost., A. nutans Grev., Stemonitis