Zs. P. Komáromy szerk.: Studia Botanica Hungarica 16. 1982 (Budapest, 1982)

Rajczy, Miklós: About the length of active life of some xerophytic cryptogams in the dry season

Materials and methods One moss and two lichen species being common on the investigated territory were used: Tortula ruralis (Hedw.) Gaertn., Meyer et Sc herb.

;; Cladonia furcata (Hds.) Schrad.

; Cladonia convoluta Lam. The measurements were carried out on a sandhill near Füiöpháza (Comit. BácsKiskun, Hungária centralis) on the territory of Kiskunság National Park. This territory is a sandy steppe on the Great Hungarian Plain. The soil is calcareous sand with pure vegetation (Brometum tectorum and Festucetum vaginatae danubiale), and in two places with sand-drift. In summer the climate is rather dry. Fig. 1 shows the daily precipitation and daily maximal and minimal temperature values of the nearest meteorological station (Izsák, cca. 10 km from it) in July 1977. The following measurements were performed from 8 p.m. 20.07.1977 till 7 a.m. 21.07. 1977. 1. Gravimetric determinations were carried out on an analytical balance in the field to four places of decimals. Two samples were taken from each species (whole little thalli from the lichens and a piece of a great tuft from the moss). All samples were put into a little box folded from aluminium foil and laid onto a small grating on the ground. Air-dry samples were weighed in the laboratory at room temperature. There was no need for oven-drying the samples because only the amount of relative changes was studied. 2. Microclimatic measurements: a recording thermometer indicated the temperature of the air at ground level. Mercuries were placed into a moss tuft; under a moss tuft (both were Tortula ruralis); into the soil at -1 cm. Air humidity was determined by an Assman Psychrometer at ground level. Fig. 1. Daily precipitation and daily maximal and minimal temperature in July, 1977. Meteorological station at the village Izsák (T - temperature; t - time)