Observation 19342: Parmotrema reticulatum (Taylor) M. Choisy

When: 2009-03-08

Collection location: Sewanee, Franklin Co., Tennessee, USA [Click for map]

Who: Chris Parrish (kitparrish)

Specimen available

Notes:
Location: 35°12’38.36"N, 85°54’0.40"W, el. 587 m, Beckwith’s Point Trail.

Substrate: Growing with other lichens on a fallen log which was quite rotten and easily pulled apart

Habitat: oak-hickory woodland near the western escarpment of the Cumberland Plateau

Characterization: ruffled lichen with marginal setae and
(1) reticulate macular pattern on thallus surface
(2) pillow-like marginal soredia
(3) undersurface black in the center, grading to brown under marginal lobes
(4) rhizines extending to lobe margins; rhizines sometimes forked

Chemistry:
cortex: C-, K+ yellow to red to dark brown
medulla: C-, K+ yellow → blood red → dark red

Similar species: Parmotrema margaritatum and reticulata are very similar, and margaritatum may even show a reticulate white macular pattern on the upper surface for which reticulata is better known. They both contain salazinic acid, so presumably their spot tests are similar. The most prominent differentiating characters seem to be the largely rhizine-free marginal areas and discrete soredial patches on narrow marginal lobes of P. margaritatum vs. rhizines occuring up to the thallus margins, sometimes forked rhizines, and coallescing, pillow-like marginal soralia of P. reticulatum (Harris and Ladd, 2005; Brodo et al., 2001).

References:
Sharnoff’s Parmotrema reticulatum gallery
CNALH images, description, and locality map, and a larger, interactive locality map.

Voucher specimen: Tennessee, Franklin County, Sewanee, Beckwith’s Point Trail, 08 Mar 2009, Chris Parrish 0004, det. Gary Perlmutter (NCU)

Common name: cracked ruffle lichen (Listed as Rimelia reticulata in Brodo, Sharnoff, Sharnoff, pp.642-643.)

Species Lists

Images

thallus, 7.1x
thallus, 10x
lobe, 25x
lobe, 32x
lobes, 25x
maculae, 50x
soredia, 16x
undersurface, 25x
undersurface, 40x
undersurface, 40x
rhizines, 25x

Proposed Names

28% (1)
Used references: Harris and Ladd, 2005; Brodo et al., 2001
56% (1)
Used references: Specimen identified at the UNC Herbarium

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= Observer’s choice
= Current consensus

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Created: 2009-03-11 13:35:09 PDT (-0700)
Last modified: 2009-03-11 13:35:09 PDT (-0700)
Viewed: 278 times, last viewed: 2019-04-08 18:20:10 PDT (-0700)