4 



NORTH AMERICAN FLORA 



[V01.UMK 7 



Spores uniformly colored. 



Sori completely destroying- spikelets. 

 Sori usually destroying inner and basal parts. 

 Sori in leaf -sheaths or blades ; spores 8-11 m. 

 Spores medium, 10-14n in length ; sori in ovaries. 

 Spores large, 13-22 m in length, the inner coat with projections. 



2. Spores often apparently smooth but at least granular under an immer- 



sion lens. 



Sori in leaves ; spores scarcely granular. 



Sori in inflorescence, sometimes confined to spikelets. 



Sori in spikelets. 



Sori rather completely destroying spikelets. 



Sori destroying only basal and inner parts. 

 Sori in ovaries ; spores apparently smooth. 

 Sori in flowers protected by perianth. 



3. Spores echinulate or verruculose (occasionally minutely or obscurely). 

 Spores small, 4-9 ji^ in length. 



Sori in leaves. 



Sori in striae or areas of considerable extent. 

 Sori pustular. 



Sori involving or aborting inflorescence. 

 Sori ovoid to subspherical ; spores 4-6 1^. 

 , Sori linear ; spores 6-11 ^ in length. 

 Sori in spikelets. 



Sori rather completely destroying spikelets. 

 Hosts; Avena. 

 Hosts : Triticum. 

 Hosts : Hordeum. 

 Sori destroying inner and basal parts. 

 Sori in ovaries. 



Spores evidently echinulate or verruculose. 



Spores variable, often elongated, olive-brown. 

 Spores rather regular, reddish-brown. 

 Spores obscurely echinulate , often appearing smooth. 

 Spores uniformly colored, 4-6 /^ in length. 

 Spores often lighter colored on one side, 5-9/*. 

 Spores medium, 9-14/* in length (see also nos. 21, 47). 

 Sori on various parts of host. 



Sori at nodes and on leaves, nodular, hispid, 

 Sori in ovaries, nodes, etc., pustular, smooth. 

 Sori usually at nodes, conspicuous, ovate to lanceolate. 

 Sori on any part of host, usually very conspicuous. 

 Sori forming elongate outbreaks, aborting inflorescence. 

 Sori in leaves. 

 Sori in striae. 



Sori involving leaves at apex of culm and aborting inflorescence. 

 Sori linear, very elongate, often 1 dm. 

 Sori elongate- ellipsoidal, 5-10 mm. 

 Sori in inflorescence (see also nos. 39, 48, 52). 

 Hosts: Syntherisma (^Panicum). 

 Hosts : Chloris. 

 Sori in spikelets, infecting entire spike. 

 Sori in ovaries (see also no. 34). 



Sori conspicuous, chiefly 3-6 mm., hispid. 

 Sori rather inconspicuous, 1-4 mm. in length. 

 Spores echinulate. 

 Hosts : Eragrostis. 

 Hosts : Boitteloua. 

 Hosts : Tridens ( Tricuspis) . 

 Spores minutelj' and obscurely verruculose. 

 Spores very conspiculously echinulate. 

 Spores with coarse, often acute tubercles. 

 Sori very inconspicuous, 1 mm. or less. 

 Spores large, 14-18 /*, rarely 12 m, in length. 

 Sori in leaves. 



Sori forming oblong pustules. 



Spores smooth or obscurely verruculose. 

 Spores echinulate. 

 Sori forming linear striae ; spores verrucose. 

 Sori in inflorescence. 



Spores light reddish -brown, minutely echinulate. 

 Spores prominently echinulate ; sorus with columella. 

 Spores dark reddish -brown, verruculose. 

 Hosts : Sporobolus. 

 Hosts : Festuca. 



4. Spores coarsely verrucose to occasionally semi- reticulate. 

 Sori on leaves. 



Hosts : Agropyrofiy Elymus, etc. 



Hosts : Phalaris. 



Hosts : Panicularia {Glyceria), Scolochloa. 



14. U. affinis. 



17. U. Crameri. 

 4. U. calcara. 



18. U. lycuroides. 

 58. U. Heufieri. 



3. U. longissima. 



13. U. residua. 



15. U. Lorentziana 



16. V. bromivora. 

 19. U. Rickerii, 

 23. U. Tillandsiae. 



21. U. Ulei. 

 31. U. minor. 



12. U. Muhlenbergiae 



22. U. chloridicola . 



9. U. Avenae. 

 11. U. Triiici. 

 10. U. nuda. 



8. U. perennans. 



24. U. olivacea. 

 27. U, sparsa. 



25. U. Sieglingiae. 



26. U. Triplasidis. 



2>6. U. Crus-galli. 



34. U. pusitdata. 



37. U. heterogeiia. 



38. U. Zeae. 



39. U. KellerTnanii. 



53, U. striaeformis. 



52. U. Dieteliana. 



48. U. Aegopogonis. 



46. U. Rabenhorstiana 



51. U. elegans. 



40. U. neglecia. 



35. U. sphaerogena. 



28. 



U. spermophora. 



29. 



U. Boutelouae. 



30. 



U. Tricuspidis. 



41. 



U, Uniolae. 



43. 



U. ornata. 



44: 



U. Sporoboli. 



42. 



U. Eriocauli. 



33. 



U. Buchloes. 



32. 



U. Hieronymi. 



54. 



U. Calamagrostidis 



49. U. Hilariae. 

 47. U. Holwayana. 



45. U. Vilfae, 



50. U. Mulfordiana 



55. U. macrospora. 

 56.' U. echinata. 

 57. U. Arthurii. 



