Cladonia pyxidata

Starting in the 1500s, the doctrine of signatures was an ubiquitous concept in European medicine. It was thought that plants looked like the organ or ailment that they cured and various lichens were adopted into the European pharmacopoeia as a result. The main medicinal lichens in early modem era Europe were Cetraria islandica, Cladonia pyxidata, Peltigera canina, Peltigera aphthosa, Usnea spp., Lobaria pulmonaria, Xanthoria parietina, and Evernia prunastri. For more details, refer to these lichens in the tables below. The widespread use of these lichens had been mostly abandoned by 1800, with the exception of Cetraria islandica, which has persisted as a medicinal lichen in parts of Europe until today. 

Lichens are found in habitats which are subjected to high temperatures, but the effects of light and water regime on photosynthesis at these temperatures has not been examined in detail. Lange (1953) recorded temperatures of 53°-69°C within or below thalli. One specimen of Cladonia pyxidata remained at 62.5° C or above for 4 hours. Lange defined the limit of heat resistance of lichens as the temperature which caused normal respiration to be reduced by one-half. Dry lichen thalli could withstand a 30 minutes exposure to temperatures from 70°C Alectoria sarmentosa) to C (Cladoniapyxidata). However, moist thalli had a much lower limit of heat resistance which varied from 35° to 46°C... 

Ramalina siliquosa, R. subfarinacea Peltigera canina, Umbilicaria cylindrica, U. pustulata, Cladonia gr. pyxidata, Usnea muricata, H. physodes, Pseudevernia furfuracea, Parmelia conspersa, Bryoria fuscescens Hypogymnia caperata, Diploica canescens, Lecanora expallens H. physodes... 

The plant growth hormone ethylene was detected in the lichen Ramalina duriaei by Epstein 281, 282). Ott and Zwoch 569) analyzed Cetraria islandica, Cladonia rangiferina, C. arbuscula, C. sulfurina, C. cornuta, C. pyxidata, Peltigera lactucifolia and Usnea aurantiaco-ater for ethylene and found it in amounts of 0.8-5.5 pl/g dry weight/ hour. The presence of hydrocarbons with 17-33 carbon atoms has been reported 317) in Cetraria nivalis, C. crispa and Siphula ceratites in other lichens C-27, C-29 and C-31 were the main hydrocarbons 765). The hydrocarbons of the odoriferous fraction of Evernia prunastri have been examined 357). 

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