256 



INDEX. 



Page. 



Pliysostegia 106, 179 



Virginiana, var. denticulata ... 13 



Phytolacca 107,180 



Phytolaccace£B 107 



Phytology, the last science to be systematic- 

 ally studied 57 



Pickerel- weed 124 



Family 124 



Pierce'sMill 20 



Pig-nut Ill 



Pigweed 107 



PUea .' 111,182 



pumila 49 



Pimpernel 96 



PimpineUa 82,162 



Pine 137 



Abundant species of 48 



Family 137 



Pine-sap 96 



Piney Branch 20, 25 



Pink 68 



Family 68 



Pin-Oak ll^j 



Pinus 137,199 



inops 48 



mitis 48 



pungens 21 



rigida 48 



Strobus 20 



Pin-weed 60 



Pinxter-flower 49, 95 



Piperaceae 52, 109 



Pipe wort 124 



Family 124 



Pipsissewa 95 



Pirus 51,78,159 



Americana 12 



arbutifolia 20 



Pitch Pine 48,137 



Pitcher-Plant Family 64 



Plagiochila 143,206 



Plane-Tree Ill 



Family Ill 



Plantaginacese 51, 106 



Plantago 106,179 



cordata 24 



Plantain FaiuUy 106 



Plantain-leaved Everlasting 89 



Plants, Probable number of, in 1830 16, 17 



Early-flowering 27, 28 



Number of (species and varieties), 

 as basis of statistical compari- 

 sons 34 



The companionship of 56 



Representative parts of 212 



that turn black in drying 222 



Whatto "do with" 237 



in the herbarium, compared to books 



in the library 237 



PlatanacesB Ill 



Platanus 111,182 



occidentalis 48 



Platygyrium 142, 204 



Pleurisy-root 97 



Plum 76,77 



Page. 



Poa 132,196 



annua 30 



brevifolia 28, 50 



pratensis 50 



sylvestris 50 



Podophyllum 63, 149 



Podostomaceae 109 



Podostemon 109, 181 



ceratophyllus 24 



Pogonatum 141, 203 



Pogcmia ; 119, 186 



divaricata 13 



pendula 13 



Poison, Directions for preparing 224 



Poison Ivy 49, 73 



Sumac • 73 



Poisoning plants 224 



Necessity for 224 



Pokeweed 107 



Family 107 



Polemoniaceae 98 



Polemonium 99, 133 



Family 98 



reptans 20 



Polygala 67,152 



ambigua 24 



cruciata 12 



lutea 12 



pauciflora 12 



setacea 12 



vorticillata 12 



PolygalacesB 51, 67 



Poly galeae 51 



Polygonaceas 108 



Polygonatum 122, 188 



latifolium 13, 238 



Polygonum 108,180 



amphibium 238 



var. terrestre 22 



dumetornm 49 



sagittatum 49 



tenue 13 



Virginianum 49 



Polymnia 89,167 



Polypetalae. Proper systematic position of 



the 53 



Polypodium 137, 199 



viilgare 50 



Polypody 137 



Polytrichum 141, 203 



Pond-Lily 63 



Poudweed 118 



Family 118 



Pontedoria 124, 189 



cordata 33,50 



Pontederiaceae 124 



Poor Man's "Weather-Glass 96 



Robin's Plantain 89 



Poplar 1 16, 117 



Poppy 64 



Family 64 



Popularisation of science 55 



Population in 1830 and 1880, 



of the District of Columbia 14, 15 



of Maryland 15- 



