naa a22 4500 510746853 CHVBK 20180411083049.0 cr unu---uuuuu 180411e20130501xx s 000 0 eng 10.1007/s13199-013-0234-2 doi (NATIONALLICENCE)springer-10.1007/s13199-013-0234-2 Armstrong R. Department of Vision Sciences, Aston University, B4 7ET, Birmingham, UK aut Development of areolae and growth of the peripheral prothallus in the crustose lichen Rhizocarpon geographicum [Elektronische Daten] an image analysis study [R. Armstrong] Areolae of the crustose lichen Rhizocarpon geographicum (L.) DC., are present on the peripheral prothallus (marginal areolae) and also aggregate to form confluent masses in the centre of the thallus (central areolae). To determine the relationships between these areolae and whether growth of the peripheral prothallus is dependent on the marginal areolae, the density, morphology, and size frequency distributions of marginal areolae were measured in 23 thalli of R. geographicum in north Wales, UK using image analysis (Image J). Size and morphology of central areolae were also studied across the thallus. Marginal areolae were small, punctate, and occurred in clusters scattered over the peripheral prothallus while central areolae were larger and had a lobed structure. The size-class frequency distributions of the marginal and central areolae were fitted by power-law and log-normal models respectively. In 16 out of 23 thalli, central areolae close to the outer edge were larger and had a more complex lobed morphology than those towards the thallus centre. Neither mean width nor radial growth rate (RaGR) of the peripheral prothallus were correlated with density, diameter, or area fraction of marginal areolae. The data suggest central areolae may develop from marginal areolae as follows: (1) marginal areolae develop in clusters at the periphery and fuse to form central areolae, (2) central areolae grow exponentially, and (3) crowding of central areolae results in constriction and fragmentation. In addition, growth of the peripheral prothallus may be unrelated to the marginal areolae. Springer Science+Business Media Dordrecht, 2013 Rhizocarpon geographicum nationallicence Prothallus nationallicence Marginal areolae nationallicence Central areolae nationallicence Radial growth rate (RaGR) nationallicence Size distribution nationallicence Symbiosis Springer Netherlands 60/1(2013-05-01), 7-15 0334-5114 60:1<7 2013 60 13199 https://doi.org/10.1007/s13199-013-0234-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s13199-013-0234-2 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Armstrong R. Department of Vision Sciences, Aston University, B4 7ET, Birmingham, UK aut NATIONALLICENCE 773 0- Symbiosis Springer Netherlands 60/1(2013-05-01), 7-15 0334-5114 60:1<7 2013 60 13199 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer