Eight general study sites were examined in the biackbmsh (Coleogyne mmosissima) zone of southwestern Utah in order to assess the impact of burning. All sites had been burned. Age since burning varied from 1 to 37 years. Plots were placed in burned areas with plots in adjacent unburned areas serving as controls. Sites were similar enough that definite trends were distinguishable despite between site variation. Recently burned areas were dominated by forbs, middle aged bums were dominated by grasses, and the oldest bums had reverted back to shrub dominance. Cryptogamic soils crusts were severely affected by burning and showed no signs of recovery after 19.5 years. Blackbrush was also severely affected and showed no signs of recovery after 37 years. Lack of recovery by blackbrush may be due to its paleoendemic nature. Future burning of stands of blackbmsh in southwestern Utah is not recommended. The blackbrush (Coleogyne ramosissima) zone of southwestern Utah is an important vegetation type occupying large areas. However, it produces relatively little livestock forage. Controlled buming has been used as a management tool during the last 20 years to remove blackbrush and increase forage production. In the nearby blackbrush zone of southern Nevada, Jensen et al. (1960) concluded that such burning was beneficial and economically feasible. However, Bowns and West (1976) state that burning of blackbrush is not desirable as a management tool since results are unpredictable. The purpose of this study was to examine blackbrush sites in southwestern Utah which have been subjected to fire and to determine what effects the burning has had on the blackbrush community.

The stem-diameter age relationships of salt cedar from 15 study sites iu central Utah were investigated. Age prediction equations were generated and found significant @<.OOl). Within rest&cd geographic arcas the stem ages of salt cedar could be estimated with fair reliability, but with substantial geographic separation results were less accurate. The impact of salt cedar invasion over prolonged periods of time was also assessed. Results indicated that the longer the community has been occupied by salt cedar the more xeric the habitat becomes. Saltcedar (Tamarix ramosissima) is a vigorous invader of pastures, moist lowlands and stream banks throughout much of the southwestern United States (Tomanek and Ziegler 1960). It is also found in dense thickets through much of central Utah (Christensen 1962). Saltcedar has the highest transpiration rates of any North American phreatophyte (Kiegler 1968) and can depress the water table often by as much as 1.2 to 2.1 m/ yr (Horton 1964). Although studies have been made of the distribution and naturalization of saltcedar (Christensen 1962, and Horton 1964) and of its ecology and habitat requirements (Tomanek and Ziegler 1960, Carman 1979), much less is known of its stem diameter: age relationship and/ or population dynamics. Studies of the growth rings of trees have been used extensively

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Variation between phytoliths produced in the laminae, inflorescence bracts, and culms of einkorn (Triticum monococcum L.) were examined. Variation in the type of phytoliths produced and in the morphometries of the various types produced was evaluated. Morphometric data were obtained using computer-assisted image analysis. Types of phytoliths produced by various plant tissues included silica cell, large and small prickle, hair cell, trichome base, stomata, sheet element, long cell, and subepidermal cell phytoliths. Laterally dendriform subepidermal cell phytoliths were unique to inflorescence tissue. Long (100–250 μm), sinuate, alate trapezoid phytoliths were unique to lamina tissue. Tukey honestly significant difference comparisons indicated that there are some significant differences (p ≤ 0.05) between the mean morphometries of silica cell phytoliths produced in the lamina tissue and those produced in the culm and inflorescence tissues. Discriminant functions based on the morphometric data obtained were effective in distinguishing between populations of silica cell phytoliths extracted from each of the plant tissue types. These results suggest that (i) when preparing reference matrial for phytolith analysis, each part of a plant should be sampled and evaluated separately, and (ii) discriminant analysis of morphometric data obtained through image analysis is a potentially valuable research tool for the further development and application of phytolith systematics. Key words: phytoliths, image analysis, Triticum monococcum.

Salt grass is an important pioneer plant in early stages of succession. The sharp‐pointed rhizomes with numerous epidermal silica cells, and the aerenchymatous network of the rhizome, leaf sheath, and roots facilitate development of the plant in heavy clays, shales, and inundated soils. In salt marshes of southern Utah, salt grass contributes to a hummock‐building process that favors localized removal of salts by capillary action and evaporation. This process provides a narrow strip of soil that is favorable for the rooting of extended rhizomes. In laboratory experiments, maximum growth for Distichlis spicata, a perennial salt marsh grass, was obtained at 15,000 ppm soluble salts in nutrient solution cultures. Comparable concentrations of salts occurred in soils of the habitat from which plants were taken. Nearly equal concentrations of sodium and potassium were found in the plant tissue where the growth of the plants was optimal; such a ratio was maintained in the plants during most of the growing season. In the field the greatest amount of growth of salt grass takes place when temperatures are cool and soil moisture is quite high during the early spring. During mid‐summer as air temperatures rise, crude protein in the plant decreases. During periods of high salt and water stress, morphological and anatomical adaptations of the stomata, salt glands, and trichomes of salt grass are important for survival. Stomata on exposed ridges of vascular bundles, where desiccation is greatest, usually are covered by four epidermal cells. In contrast, stomata found in the grooves between vascular bundles tend to be uncovered. The salt gland is composed of a large basal cell and a cap cell and actively excretes (in a diurnal rhythm) excess sodium, potassium, and chloride ions. A mechanism for salt excretion from this gland is postulated. The silica‐containing trichomes on the leaves may play a role in cooling the leaf under conditions of high solar radiation and also serve to protect the plant against attack by herbivores.