. The Canadian field-naturalist. Natural history. E 1. Pale-coloured Nardiis stiicta on Guindon soil in Site I showing abrupt margins of stand where soil type changes to Ivry. Dead Solidago rugosa conspicuous between clumps. Photo- graphed Oct. 22, Figure 2. Naniiis stricla showing closely-packed leafy shoots on rhizomes, and roots penetrating only to base of top layer of soil. soils is low, but Nardus stricta is a true calci- phobe and grows on acid soils low in nutrients in Europe (Chadwick 1960). These Guindon and Ivry soils are of Precambrian alluvio-lacus- trine origin (Lajoie 1960
. The Canadian field-naturalist. Natural history. E 1. Pale-coloured Nardiis stiicta on Guindon soil in Site I showing abrupt margins of stand where soil type changes to Ivry. Dead Solidago rugosa conspicuous between clumps. Photo- graphed Oct. 22, Figure 2. Naniiis stricla showing closely-packed leafy shoots on rhizomes, and roots penetrating only to base of top layer of soil. soils is low, but Nardus stricta is a true calci- phobe and grows on acid soils low in nutrients in Europe (Chadwick 1960). These Guindon and Ivry soils are of Precambrian alluvio-lacus- trine origin (Lajoie 1960). Nardus has tightly folded leaves with a high proportion of sclerenchyma tissue and a correspondingly low percentage of chlorophyll tissue (Figure 4). The rhizomes are unique among grasses in Can- ada in having the bundles of leaf sheaths packed so closely, two or three abreast, that there were as many as ten to fifteen on 2 cm lengths of rhizome (Figure 2). The density of the clump, and the leaf form are presumably xerophytic modifications, cutting down water loss. However, the apparent inability of Nardus stricta to thrive on the Ivry soil while growing well on the Guindon soil immediately bordering it, might indicate an ecotype which under our particular climate conditions, reached the limit of its tolerance of low water and low nutritive supply on the latter soil. Significant in this re- gard is the fact that the European plant is described as having a horizontal spreading root system of 30-40 cm, and a depth penetration of 50 cm or more, while our plants had no spread- ing root system and a depth penetration of only 17-20 cm. J. de Coulon, quoted by Chadwick (1960), states that its drought resistance is largely due to its extensive root system. If this type of growth is general in Europe it could make Nardus less sensitive to the water content of soils there than in our area. Some importance may be attached to the fact that the top layer of the Guindon soil contained amo
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