1. INTRODUCTION TO LICHENS

2. What is a lichen? Lichens are fungi that associate with algae. Most are ascomycetes, a few are basidiomycetes. ascomycetes basidiomycetes

3. Are lichens a ‘natural’ group? they have evolved many separate times

4. Are lichens a ‘natural’ group? they have evolved in basidiomycetes as well

6. photobionts

7. photobionts - Trentepohlia

8. photobionts - cyanolichens sometimes look grey, or the dull blue-grey cyanobacteria seen when thallus is broken

9. photobionts - cyanolichens some cyanolichens swell when moist (but most do not)

10. photobionts - cephalodia

12. crustose lichens - cracked

13. crustose lichens - smooth

14. crustose lichens - leprose

15. crustose lichens - endolithic

16. squamulose lichens

17. squamulose lichens

18. foliose lichens

19. fruticose lichens

20. fruticose lichens

21. fruticose lichens – can be flattened

22. fruticose lichens – can be flattened

23. crustose with lobes: placodioid

24. filamentous shape is determined by photobiont

25. foliose lichens - rhizines

26. foliose lichens - cilia

27. pseudocyphellae

28. vegetative reproduction the lichen needs to disperse the fungus and the alga together

29. vegetative reproduction soredia isidia (in a soralium)

30. vegetative reproduction soralia

31. vegetative reproduction - soralia

32. vegetative reproduction - soralia

33. vegetative reproduction – soralia position is useful in species identification

34. vegetative reproduction – isidia

35. vegetative reproduction – phyllidia

36. vegetative reproduction – pseudoisidia

37. vegetative reproduction isidioid soredia/isidiomorphs – soredia which stay in place and become corticate

38. vegetative reproduction blastidia schizidia

39. vegetative reproduction - blastidia often very similar to soredia

40. sexual reproduction apothecium perithecium

41. sexual reproduction - apothecia

42. sexual reproduction - apothecia

43. sexual reproduction – apothecia no thalline margin thalline margin (lecideine) (lecanorine)

44. sexual reproduction – apothecia no thalline margin

45. sexual reproduction – apothecia convex; margin absent or almost

46. sexual reproduction – apothecia elongated apothecium (lirella)

47. sexual reproduction – apothecia Stalked, with a dry spore-mass

48. sexual reproduction – perithecia

49. sexual reproduction – perithecia perithecia sunk in pits in limestone

50. asexual spores called conidia usually in pycnidia

51. asexual spores apothecia together with pycnidia

52. asexual spores apothecia together with pycnidia, immersed in surface of limestone

53. basidiolichens

54. basidiolichens

55. When is it not a lichen?

56. When is it not a lichen, but it is a ‘lichen’?