Collection location: Sewanee, Franklin Co., Tennessee, USA [Click for map]
Location: 35°13’21.51"N, 85°57’3.86"W, el. 572 m, Rutledge Point Trail.
Substrate and habitat: Growing on and through a layer of mosses on a near vertical sandstone cliff in a patch of rock given to seepage, in oak-dominated eastern deciduous woodland at the western rim of the Cumberland Plateau.
Identification: Specimens of this lichen were identified by Gary Perlmutter at the UNC Herbarium as Peltigera polydactylon. Gary remarks that the “Peltigera is possibly two taxa, one with small lobes and another with large ones. I’ve split the sample into 031 (small lobed) and 031a (large lobed). Both are P. polydactylon s. lat. While Brodo et al. (2001) keys the large lobed to possibly P. neopolydactyla, Harris & Ladd (2005) are more cautious: ‘We do not pretend to understand the P. polydactylon complex in eastern North America.’ I’ve grown to err on the side of caution, and this being more recent than Brodo et al., am following Harris and Ladd.”
Interesting to compare the relatively sparse, dark, bushy or cable-like rhizines in these photos with the dense, white, smartly regimented, sabre-tooth rhizines in Observation 13159.
Voucher specimen: Tennessee, Franklin County, Sewanee, Rutledge Point Trail, 22 Mar 2009, Chris Parrish 0031, det. Gary Perlmutter (NCU)
Common name: many-fruited pelt (The apothecia in this species are striking, but I haven’t found any yet! See the photos in Observation 13159 and in Brodo, p.518.)
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Yes, I’m still very unsure of the ID of observation 13159: depending on how you classify the veins (which are not visible in my photos) it may also key out to P. degenii; and depending on how broad and wavy the lobes are, it could key out to P. neopolydactylon. Actually, I think I would go with that knowing what I know now, but that is still too little to be sure, and Gary’s comments about the taxonomic state of thes polydactyon group convince me not to try!
As for rhizines. In this group they should “mostly taper to a point” (Trevor Goward’s key). I see at least one of yours tapering to a point (e.g. image 42161). I believe it is important to look at the rhizines near the edge that are not yet actually attached to the substrate. (All attached rhizines will eventually splay out upon touching the substrate.) I don’t actually see any “pristine” rhizines in your photos, interestingly. Not sure what that means. So I would be hesitant to classify your rhizines as “bushy” based on the photos. As for color… Well, you can only see the very youngest rhizines on my observation; generally older rhizines turn darker in my limited experience, even in species which supposedly have white undersides.
Created: 2009-04-27 23:29:38 EDT (-0400)
Last modified: 2009-04-27 23:29:38 EDT (-0400)
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