CIRCULAR ARRANGEMENT OF STIPAGROSTIS-CILIATA CLUMPS IN THE NEGEV, ISRAEL AND NEAR GOKAEB, NAMIBIA

Circles of tufts or tuft remnants of the perennial grass Stipagrostis ciliata were found in sandy soils in desert areas of Israel and Namibi a. It is suggested that such a circular pattern is due to vegetative p ropagation of this and other species by means of horizontal rhizomes. The central part of the older specimens dies and detached offspring ra mets develop in the periphery of the genet. Other species with similar arrangement of ramets are Stipagrostis obtusa, Asphodelus ramosus (Li liaceae), and Cyperus macrorrhizus (Cyperaceae). The shrubby dicotyled ones Calligonum comosum and Artemisia monosperma, which also produce c ircles of clumps, are capable of reproducing vegetatively by means of adventive roots and new branches, which are the extension of buried br anches in the periphery of the genet.