Cnothera, 54. 
Old Witch Grass, 130. 
Oleacee, 88. 
Olive Family, 88. 
Onagracee, 53. 
Onoclea, 135. 
Onopordon, 68. 
Opegrapha, 154. 
Ophioglossacez, 132. 
Ophioglossum, 132. 
Opuntia, 55. 
Orange Grass, 37. 
Orchard Grass, 125. 
Orchidacez, 107. 
Orchis, 107. 
Orchis Family, 107. 
Origanum, 81. 
Ornithogalum, 112. 
Orobanchacee, 77. 
Orpine Family, 52. 
Orthotrichezx, 139. 
Orthotrichum, 139, 171. 
Oryzopsis, 124. 
Osgood, George, 15, 21. 
Osier Willow, 99. 
Osmorrhiza, 19, 57. 
Osmunda, 136. 
Ostrich Fern, 135. 
Ostrya, 98. 
Oswego Tea, 82. 
Oxalis, 41. 
Painted Cups, 80. 
Painted Trillium, 111. 
Pale Golden-rod, 638. 
Pale Laurel, 73. 
Panicum, 129. 
Pannaria, 151. 
Papaveracee, 32. 
Paper Birch, 98 # 
Parmelia, 150. 
Parnassia, 51. 
Paronychiee, 39. 
Parsley Family, 55. 
192 
Parsnip, 56. 
Partridge Berry (Mitchella), 60. 
Paspalum, 129. 
Pastinaca, 56. 
Pasture Thistle, 68. 
Peach, 48. 
Pearlwort, 39. 
Pearly Everlasting, 67. 
Pedate Violet, 35. 
Pedicularis, 80. — 
Pellia, 144. 
Peltandra, 103. 
Peltigera, 151. 
Penthorum, 52. 
Pepper-grass, 34. 
' Peppermint, 81. 
Pertusaria, 153. 
Petrocelis, 160. 
Petunia, 86. 
Pheosporee, 163. 
Phalaris, 129. 
Phegopteris, 134. 
Pheum, 123. 
Philadelphus, 51. 
Phlox, 84. 
Phlox Family, 84. 
Phragmites, 127. 
Phraseolus, 47. 
Phryma, 80. 
Phyliitis, 165. 
Phyllophora, 160. 
Physalis, 85. 
Physcia, 150. 
Physcomitrium, 141. [170. 
Physcomitrium (Gymnostomum), 
Physostegia, 82. 
Phytolacca, 89. 
Phytolaccaceez, 89. 
Picea, 101. 
Pickerel-weed, 114. 
Pickerel-weed Family, 114. 
Pickering, Charles, 23. 
Pignut Hickory, 96. 
Pigweed, 89. 

