COMPARISON OF GROWTH AND MORPHOLOGY OF ATRIPLEX-CANESCENS VARIETIES OCCIDENTALIS AND ANGUSTIFOLIA

Two varieties of Atriplex canescens from a disturbed site in the Navaj oan desert of the Colorado Plateau were compared. Variety angustifolia could be distinguished from var. occidentalis by its greater fruit di ameter (>1.5 cm) and leaf width:length ratio (>10), and absence of met hoxy flavonols in the leaves. Variety angustifolia was the less common variety on the site but was clearly superior to Mr. occidentalis in g rowth and water use efficiency of seedlings in a greenhouse study. See dlings of both varieties were transplanted into caliche and dune soil at the site; growth and survival were followed over the establishment year. Variety angustifolia had 3 to 6 times greater canopy volume than var. occidentalis on both soil types, but the differences were greate st on dune soil, in which var. occidentalis had only 32% survival and showed little growth whereas var. angustifolia had nearly complete sur vival and positive growth over the establishment year. The results sup port other studies suggesting the diploid var. angustifolia is adapted to rapid establishment on unstable dune soils, whereas the slower-gro wing var, occidentalis may be adapted for heavier soils which retain m oisture longer than dune sand. Variety angustifolia was the better cho ice of germplasm for revegetation of this disturbed site.