IOWA ACADEMY OF SCIENCES. 



161 



EXPLANATION OF PLATE. 



No. No, 



1. Acrostichum aureum. 31. 



2. Polypodium vulgare. 32. 



3. Polypodium falcatum. 33. 



4. Polypodium Californicum. 34. 



5. Polypodium pectinatum. 35. 



6. Polypodium aureum. 36. 



7. Gymnogramme triangularis. 37. 



8. Xotholsena ferruginea. 38. 



9. Xotholccna nivea. 39. 



10. Vittaria lineata 40. 



11. Adiantum capillus-Veneris. 41. 

 12 Pteris longifolia. 42. 



13. Pteris cretica. 43. 



14. Pteris longifolia. 44. 



15. Cheilanthes microphylla. 45. 



16. Cheilanthes Alabamensis. 46. 



17. Cheilanthes viscida. 47. 



18. Cheilanthes lanuguinosa. 48. 



19. Cryptogramme acrostichoides. 49. 



20. Pellaea gracilis. 50. 



21. Pellaea atropurpurea. 51. 



22. Pellaea andromedasfolia. 52. 



23. Pellaea ternifolia. 53. 



24. Ceratopteris thalictroides. 54. 



25. Lomaria spicant. 55. 



26. Blechnum serrulatum. 56. 



27. Woodwardia radicans. 57. 

 28 Asplenium pinnatifidum. 58. 



29. Asplenium trichomanes. 59. 



30. Asplenium firmum. 



These tables show that there are differences with respect to 

 size and character of species; in some genera species show 



marked differences in size of spores. Schizaea pusilla, the 



smallest of our ferns, has the largest spores of any species 

 examined, Onoclea Struthiopteris has relatively small spores. 



Asplenium Thelypteroides. 

 Asplenium Filix-foemina. 

 Scolopendrium vulgare. 

 Camptosorus rhizophyllus. 

 Phegopteris calcarea. 

 Phegopteris Dryopteris. 

 Phegopteris Polvpodioides. 

 Phegopteris alpestris. 

 Aspidium spinulosum. 

 Aspidium Oreopteris. 

 Aspidium Noreboracense 

 A spidium Thelyp teris. 

 Aspidium acrostichoides. 

 Aspidium unitum. 

 Aspidium Lonchitis. 

 Xephrolepis exaltata. 

 Cystopteris bulbifera. 

 Onocloa sensibilis. 

 Woodsia obtusa. 

 Woodsia livens is. 

 Woodsia glabella. 

 Dicksonia punctilohula. 

 Trichomanes Petersii. 

 Lygodium palmatum. 

 Aneimia adiantifolia. 

 Aneimia Mexicana. 

 Osmunda cinnamomea. 

 Osmunda regalis. 

 Schizsea pusilla. 



Fig. 56. Spores of ferns, 

 Ameimia Mexicana. 



11 



Fig. 58. Osmunda 

 regalis. 



Fig. 59. Schizola 

 pusilla. 



