The algae and fungi occurring in snowbanks in the Front Range of the Colorado Rocky Mountains are described and discussed. Whenever possible, details of the life cycle are given and correlated with reports in the literature. The effect of light on presence of carotenoid pigments is discussed for several species. The following organisms are reported: Carteria nivale; Chlamydomonas nivalis, Chlamydomonas spp.; Chodatella brevispina, Chodatella granulosa; Scotiella cryophila, S. nivalis, S. polyptera; Koliella nivalis; Rhizophydium sp.; Chionaster nivalis.

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Pisolithus tinctorius (Pers.) Coker & Couch was evaluated as an ectomycorrhizal associate of sweet birch (Betula lenta L.). Sand culture and mine soil growth media were employed, and three fertilization treatments were imposed by application of differing Hoagland's nutrient solution #2 concentrations. The high fertilization treatment suppressed mycorrhizal formation by P. tinctorius in both growth media, while the medium rather than the low treatment induced the most extensive colonization by this mycobiont. Seedlings with induced P. tinctorius mycorrhization exhibited enhanced above-and below-ground growth ac-cording to shoot dimensions and dry weight and root weight and length. However, these responses were frequently absent with high fertilization, especially in the mine soil. Inoculated seedlings had higher foliar N, P, and K concentrations overall but lower Ca, Mg, and S concentrations than uninoculated seedlings. Those with P. tinctorius also had lower concentrations of several potentially phytotoxic trace elements, specifically Zn, B, Mo, and Al. Furthermore, xylem pressure and soil water potentials measured during a simulated drought episode indicated that water uptake was enhanced by these mycorrhizae. Again, however, the above physiological responses were often compromised by high fertilization. Collectively, these results indicate that P. tinctorius is a viable mycobiont for the inoculation of sweet birch, and when substrate fertility is not excessive, can avail this host of physiological benefits that result in substantial growth enhancement.

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The nature and the dynamics of the terrestrial vegetation are discussed, along with observations on the effects and consequences of current and planned activities on Amchitka.