DIVERSITY,LIFE HISTORY,AND ECOLOGY OF TRENTEPOHLIA AND PRINTZINA (TRENTEPOHLIALES,CHLOROPHYTA) IN URBAN HABITATS IN WESTERN IRELAND 1

On the basis of field and culture investigations, five species of the genera Trentepohlia and Printzina were found to occur in urban habitats in western Ireland: Trentepohlia abietina (Flotow) Hansgirg, T. aurea (Linnaeus) Martius, T. iolithus (Linnaeus) Wallroth, T. cf. umbrina (Kützing) Bornet, and Printzina lagenifera (Hildebrandt) Thompson et Wujek. These species formed perennial populations on a variety of substrata. T. abietina occurred on bark of trees; T. cf. umbrina occurred on stone walls; and P. lagenifera grew on several substrata, mainly cement and asbestos sheeting. T. aurea and T. iolithus were found on old concrete and cement walls; in particular, the latter species formed characteristic, extensive, deep‐red patches on many buildings. In culture, best growth and reproduction of these species were observed at 10 and 15° C, 16:8 h light:dark. Both in culture and in the field, reproduction took place by release of biflagellate swarmers behaving as asexual spores, germinating to produce new plants without any evidence of sexual fusion; release of biflagellate swarmers in the field was generally observed in all seasons throughout a whole annual cycle. Confirmation of the occurrence of sexual reproduction in Trentepohlia was not obtained.