December 2012 Number 1 - Utah Native Plant Society

Utah Native Plant Society
ing the distant relationship between it and the other
Phacelia samples. This was a consequence of the large
number of AFLP bands that were polymorphic between
P. crenulata and the other three species (Table 1).
PCA was then used to analyze the relationships between
P. argylensis, P. glandulosa, and P. argillacea.
The first two principal components represented 9.2 and
7.2% of the total variation. The P. argillacea samples
clearly grouped separately from samples of the other
two species (Figure 2). In contrast, P. argylensis
grouped closely with the herbarium-collected P. glandulosa
group, calling its status as a separate species into
question. The field-collected western Colorado P. glandulosa
was most distant from the herbarium-collected P.
glandulosa group, as was also indicated by the large
number of polymorphic bands between these two sets of
collections, suggesting that it perhaps represents an undescribed
taxon within the group (Table 1).
When PCA was applied to data from the P. argillacea
samples from both populations and among different
years, the first two principal components, which explained
7.5 and 2.9% of the total variation, provided
enough separation to compare populations and years
(Figure 3). The resulting data grouped each sample with
cohorts from the same year more closely than by population.
For example, there was no overlap between
Tucker 2006 samples and the 2004 and 2008 samples
from the same population. Similarly, there was no overlap
between Railroad 2008 samples and the 2006 and
2007 samples of the same population. In addition, individuals
from the Railroad population were surrounded
Figure 2. Scores on the first two axes from Principal Components Analysis of AFLP (amplified fragment length
polymorphism) data for three species of Phacelia. The P. glandulosa point near the lower left hand corner of the
graph represents two bulked field-collected samples from closely adjacent populations; all other points represent individual
plants, or multiple individuals with identical genotypes.
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