. The Canadian field-naturalist. 332 The Canadian Fdeld-Naturalist Vol. 118. NNTTTTNNTF Figure 2. Digestion of the chloroplast DNA region trnT-tmV with restriction enzyme Alul for Saxifraga nivalis (N), S. tenuis (T) and S. foliolosa (F). The first lane contains a 100 bp DNA size marker (M). Note absence of the upper band on S. nivalis. Discussion The principal component analysis confirms that the S. nivalis complex in the Canadian Arctic is represent- ed by two principal morphotypes, appearing as adjacent clusters on the PCA graph. The several plants occu- pying an intermediate position betwe
. The Canadian field-naturalist. 332 The Canadian Fdeld-Naturalist Vol. 118. NNTTTTNNTF Figure 2. Digestion of the chloroplast DNA region trnT-tmV with restriction enzyme Alul for Saxifraga nivalis (N), S. tenuis (T) and S. foliolosa (F). The first lane contains a 100 bp DNA size marker (M). Note absence of the upper band on S. nivalis. Discussion The principal component analysis confirms that the S. nivalis complex in the Canadian Arctic is represent- ed by two principal morphotypes, appearing as adjacent clusters on the PCA graph. The several plants occu- pying an intermediate position between the two clus- ters displayed a somewhat intermediate morphology, but nevertheless could readily be assigned to one of the two taxa. For example, several specimens of S. nivalis from Prince Patrick Island (, Gillespie & Consaul 6869-4, 6926a-3) were very small with slender flowering stems, characters typical of S. tenuis, but otherwise had the morphological characteristics of S. nivalis. Although character states or ranges overlapped for the majority of characters examined, differences between the two taxa were statistically significant for all quantitative and for three qualitative characters. Morphological variability A significant amount of variance was observed for most characters measured. Since the S. nivalis complex is considered an environmental indicator (Aiken et al. 1998, 2000*), the variability observed may be due to phenotypic plasticity and variation in environment. For instance, S. nivalis plants growing in harsher habitats are usually shorter and less robust (, the very short plant shown in Figure 3) than those grow- ing in more nourishing environments. Also plants of S. nivalis may be taller with more slender stems in shady microhabitats as a result of etiolation. Another contributor to variance is the time of collection. Since stems elongate in the fruiting stage, particularly in S. nivalis, plants collected later in the season are more likely to
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