xiii 
Plantago, 57, 83. 
Platea, 80 
Platanthera, 189. 
Platygrapha, 238. 
Pleospora, 131, 279, 323. 
Pleurocybe, 238. 
Pleuropetalon, 178. 
Pleurosigma, 502. 
Pleurotus, 56, 340. 
Plicatura, 341. 
Poa, 310, 327, 344. 
Poacites, 123. 
Podophyllum, 358. 
Podosira, 502, 503. 
Podosordaria, 540. 
Pogonia, 370, 552, 589. 
Polemonium, 252. 
Polychidium, 240. 
Polygonella, 47, 167. 
Polygonum, 46, 50, 167, 220, 243, 334, 
344, 353, 421, 541. 
Polypodium, 216, 219, 260, 324, 432. 
Polyporus, 82, 146, 168, 326, 340, 370, 
541. 
Polystictus, 125, 323, 340. 
Polystroma, 239. 
Pontederia, 59. 
Populus, 278. 
Porella, 512. 
Poria, 56, 277, 340. 
Porpeia, 501. 
Portulaca, 178, 186, 421. 
Portulacaria, 178. 
Potentilla, 1, 91, 166, 249, 326. 
Pratia, 387. 
Prenanthes, 353. 
Primula, 160, 355. 
Prionodon, 215. 
Prosthemium, 31, 163. 
Protococcus, 77. 
Prunus, 44, 167, 570. 
Pseudauliscus, 504. 
Pseudotsuga, 167. 
Psilocybe, 144, 326. 
Psora, 239. 
Psoroma, 240. 
Psorotichia, 240. 
Pterigiopsis, 240. 
Pteris, 103, 160, 409, 469, 588. 
' Pterocactus, 167. 
Pterotheca, 504. 
Pterula, 56. 
Puccinia, 86, 163, 168, 208, 282, 323, 
324, 341, 457, 508, 539, 540, 591. 
acinar ; 
Pulsatilla, 417. 
Py 
Pyrenopsidium, 240. 
Pyrenopsis, 240. 
Pyrenothamnia, 241. 
Pyrgillus, 238. 
Pyrrocoma, 455. 
Pyrus, 167. 
Pyxilla, 502. 
Pyxine, 239, 341. 
Quamoclit, 212. 
Quercus, 31, 62, 278, 280, 285, 291, 326, 
320, 438, 448, 460, 460, 473, 527, 
542, 591. 
Radulum, 56. 
Ramalina, 239. 
Ramularia, 472. 
Ranunculus, 58, 245, 310, 362. 
Raphidostegium, 216, 367. 
Ratibida, 410. 
Ravenellia, 540. 
Reseda, 581. 
Reticularia, 69. 
Rhabdonema, 502. 
Rhabdonia, 59. 
Rhabdoweisia, 367. 
Rhamnus, 456, 471. 
Rhaphidostegium, 215. 
Rhexia, 155, 332. 
Rhizocephalum, 162, 386. 
Rhizopus, 480. 
Rhododendron, 64, 569, 586. 
Rhodora, 586. 
Rhus, 130, 407, 462, 485. 
Rhynchosia, 266 
Rhynchostegiella, 216. 
Rhynchostegium, 213, 314. 
Rhytisma, 285. 
Ribes, 57, 58, 93, 164, 276, 325, 460 467. 
Ricasolia, 240. 
Riccia, 321. 
Rinodina, 239, 447, 539- 
Robinsonella, 369. 
Rocella, 238. 
Romanzoffia, 344. 
Romneya, 484. 
Roripa, 58, 362. 
Rosa, 456, 483. 
Roseanthus, 274. 
Rosellinia, 126, 277, 323, 541. 
Rotala, 154. 
Rottboellia, 21. 
Rubus, 129, 279, 563, 570. 
Rudbeckia, 410. 
Ruellia, 157. 
Riilingia, 417. 
Rumex, 273. 
Rutilaria, 502. 
Russula, 340. 
| Sabbatia, 26, 165, 332. 
