Pyrola

Abstract: Four hundred and eighty plants in northern California from 27 taxa in the Ericaceae and 5 in the Pyrolaceae were surveyed for presence of ectomycorrhizae, arbutoid, or ericoid mycorrhizae between September 1977 and April 1978. Of these, 337 in the Ericaceae and 8 in the Pyrolaceae had one or more types of mycorrhizae.At least 88% of the plants of larger shrubs or trees (Arbutus menziesii or Arctostaphylos spp.) were mycorrhizal in various locations in northern California. Of the plants in the remaining twenty-two taxa that were mycorrhizal, 67–100% had ectomycorrhizae or arbutoid mycorrhizae. Twenty-three taxa of ericaceous or pyrolaceous plants in the genera Cassiope, Gaultheria, Kalmia, Ledum, Leucothoe, Phyllodoce, Rhododendron, Vaccinium, Pyrola, and Chimaphila were also mycorrhizal. The type and abundance of mycorrhizae appear to depend on as yet undefined ecological factors.Ectomycorrhizae (including the Cenococcum type) or ericoid mycorrhizae are reported for the first time in Arbutus, most Arctost...

Abstract: The small subfamily Pyroloideae, comprising four genera, is unusual in Ericaceae because of its nearly herbaceous habit, largely free petals, and tendencies toward leaflessness. A surprising number of hypotheses exist with respect to the relationships among these genera. Parsimony analysis of 23 morpholog- ical characters gave a pattern that is largely congruent with that obtained from analysis of ITS sequences. Two sister clades of monophyletic/monospecific genera are resolved-Chimaphila + Moneses and Orthilia + Pyrola. Relationships among three species of Chimaphila are not clearly resolved. Some structure is present within Pyrola, with two strongly supported clades (P picta + PR aphylla + PR chlorantha and P elliptica + P minor). The placement of P minor is unsuspected; most past classifications have segregated it from other Pyrola due to its short, straight style (as opposed to a longer, curved style). Developmental study reveals that the style terminates elongation early, so that in fact it is not clear which style orientation is present. The overall bud-like nature of the flower in P minor further suggests a juvenile morphology relative to other Pyrola. The developmental information, in combination with its position on the cladogram, indicates a pae- domorphic origin for the floral morphology of P minor.

Abstract: The northern temperate genus Pyrola L. is the largest and arguably the most taxonomically complex element in the tribe Pyroleae (Ericaceae). Here we present a molecular phylogenetic study with extensive sampling comprising 26 ingroup and 7 closely related taxa. The results, based on parsimony and Bayesian analyses of nuclear (ITS) and chloroplast (atpB-rbcL, trnS-trnG, trnL-trnF) DNA sequences, add substantially to our understanding of relationships within this diverse group and call for taxonomic changes. Pyrola is confirmed as a monophyletic group with two redefined sections and six series: P. sect. Pyrola (P. ser. Pyrola, ser. Ellipticae and ser. Rugosae) and P. sect. Scotophylla (P. ser. Japonicae, ser. Scotophyllae and ser. Chloranthae). Members of each respective section and series share similar morphological traits and/or geographical distributions. For the potential hybrids P. media and P. faurieana, the maternal donor was identified by their close affinity to P. minor in the chloroplast trees whereas the paternal donor remained unclear.