Total macro fungus frequency in closed forest associations of the Laurentide Mountains varied little (147 – 185 %) from one to another. The macrofungal flora of the deciduous forest was composed mainly of many infrequent species, whereas coniferous forests had few, but very frequent, macrofungi. Total frequency was significantly lower (15%) in open stands of the spruce–cladina association. Species richness decreased gradually (from 125 to 34 species) towards the north and with increasing altitude. Both the Simpson and the Shannon–Wiener diversity indices were significantly lower in the coniferous forest when compared with the deciduous forest. This decrease in diversity was due to the scarcity of saprophytic fungi in mor humus, whereas the number of ectomycorrhizal species remained constant. The diversity of saprophytic fungi was related significantly to that of vascular plants, whereas the diversity of ectomycorrhizal macrofungi was related mainly to the percent cover of ectomycorrhizal hosts. A total of 195 species of macrofungi were recorded for the study sites. In the maple – yellow birch forest, most of the macrofungi were saprophytic members of the Tricholomataceae, Hygrophoraceae, Strophariaceae, and Clavariaceae, many being exclusive in this association. However, each biological group had approximately equal frequency (44–54%) and richness (37–45 taxa). Species composition of the coniferous forest differed from the former in the clear dominance of ectomycorrhizal macrofungi from the Cortinariaceae, Russulaceae, and the Boletaceae. In the black spruce – cladina association, saprophytic fungi were scarce and ectomycorrhizal species were also relatively infrequent. In all the sites, the equitability of macrofungal frequency was high, as seen by the high proportion of rare species. The decline in species richness observed in this study, when moving from deciduous to coniferous forests, corresponds well with the increase in environmental rigor and instability, as well as the decrease in the diversity of organic substrate and species of vascular plants.

At Mount Albert, Quebec, many taxa are found exclusively on either serpentine or amphibolite contiguous formations. This exclusivity is clearly more noticeable within the saxicolous lichens than within the other groups. Serpentine seems to be an unfavourable substratum for the growth of saxicolous lichens. There are more infrequent taxa on serpentine than on amphibolite. The saxicolous, muscicolous, and terricolous lichen flora and the lichenicolous fungi of the plateau include 202 taxa, most of which have an arctic affinity. Of these taxa, 36 are recorded for the first time in Quebec, 16 in Canada and, 11 in North America. The ecological influence of serpentine on the lichens is, in many aspects, similar to that observed on vascular plants.

Observations were made in a sugar maple (Acer saccharum Marsh.) stand on the phenological response of three geophytes, Claytonia caroliniana, Erythronium americanum, and Trillium erectum, to solar radiation and temperature. The three species started development when the ground was partly covered with snow. The peak of the leafing and flowering stages occurred prior to the leaf development of the maple canopy. Two of the geophytes, Claytonia and Erythronium, completed their life cycle prior to leaf development in the canopy. The life cycles appear to be strongly influenced by temperature and solar radiation.

No abstract

The apical and floral development of Claytonia caroliniana var. caroliniana has been studied concurrently with soil temperature, in a sugar maple forest of the Stoneham mountain, Québec. Apical cellular activity begins early in May, while the flowering stems of the year are present. At the beginning of July, external apical development becomes visible. In the first days of August, 9 months before flowering, the foliar and floral structures of the next year are already present in the soil. Meiosis takes place at the beginning of October and first pollen mitosis follows shortly after, in the middle of the same month. From that time, well developed individuals, without chlorophyll, are present just under the litter. They can occasionally turn green and reach the upper surface of the litter in November or December, where they will spend wintertime under the snow, at a temperature oscillating between 0 and −4 °C. This behaviour is quite close to the survival strategy of hemicryptophytes. The active epigeous growth period begins in the middle of April, with the melting of snow. Second pollen mitosis and flowering take place at this time, rapidly followed by seed setting, dissemination, and destruction of the aerial portion of the plant. Cytoecological investigations to study possible influence of environmental factors on chromosomal anomalies in primordia should thus be conducted during the year preceding the flowering of Claytonia.