Desiccation tolerant vascular plants of southern Africa

Abstract

Drought tolerance limits are given for 36 new 'resurrection plants', sufficient to double the number of desiccation tolerant plants reported from southern Africa. Tolerance limits for angiosperm examples are usually better than those for ferns. Air-dry foliage survives for 1/2 to 5 years or more, unless stored in humidities above 50% RH Abbreviation: RH = relative humidity . Dehydration is sufficiently slow (usually 2-3 days) to allow the possibility of a tolerance induction process, like that found in Borya nitida. Rehydration after rain is usually complete in 1/2 to 1 day. A significant proportion of rain is absorbed through the leaf surface, but there is no evidence of appreciable rehydration from dew.Resurrection plants are usually pioneers in xeroseres, but they often lack xeromorphic characteristics. Anthocyanin pigmentation during drying is a reliable indicator of viability in some species.