Prickly lettuce, 168 Prickly sida, 146 Prostrate amaranth, 127 Prunella, 155 PU-BES´CENT, clothed with soft and rather short hairs. Pulse family, 139 Purple Jimsonweed, 155 Purple-stemmed beggar-ticks, 163 Purslane family, 131 Purslane speedwell, 157 Pusley, 131 Quack grass, 110 Ragweed, 160 Ranunculaceae, 131 Ranunculus, 131, 132 RA´PHE, the adherent funiculus connecting the hilum and chalaza in anatropous or amphitropous ovules or seeds. Red clover, 141 Red-seeded dandelion, 170 Red root, 153 RE-TIC´U-LATE, in the form of network. Rhus, 145 Rib-grass, 158 Rocket, yellow, 133 ROOT, the descending axis which is destitute of leaves or nodes. ROOT STOCK, rhizome, a stem usually subterranean and more or less thickened, producing young branches. Rosaceae, 138 Rose family, 138 Rough cinquefoil, 139 Rough pigweed, 127 Rudbeckia, 169 Rugel's broad-leaved plantain, 159 Rumex, 121, 122, 123 Running mallow, 146 Rush family, 118 Rush, slender, 118 Rush, spike, 118 Russian thistle, 126 Rutabaga, 133 Rye, 116 Salsify, 170 Salsola, 126 Sand-bur, 112 Sand plantain, 158 Sand rocket, 135 Sandwort, 129 Saponaria, 129 Scarlet clover, 141 Scleria, 128 Scrophulaceae, 156 Secale, 116 Sedge family, 118 Sedum, 138 Self-heal, 155 Setaria glauca, viridis, 117 Sheep sorrel, 122 Shepherd's purse, 134 Sherardia, 159 Shore knot-weed, 120 Sida, 146 Silene, 129, 130 Silvery cinquefoil, 138 Sisymbrium, 137 Sleepy catchfly, 129 Slender pigweed, 127 Slender nettle, 119 Slender rush, 118 Small alyssum, 132 Smaller burdock, 162 Small-flowered crane's bill, 142 Small-flowered crowfoot, 131 Small-fruited false flax, 134 Smut-weed, 120 Solanaceae, 155 Solanum, 155, 156 Sonchus, 169 Sorrel, 121 Sour dock, 121 Sow-thistle, 169 Spanish dodder, 151 Spear grass, 116 Speedwell, 157 Spergula, 130 SPIKE´LET, a small or secondary spike, as found in grasses. Spotted spurge, 144 Spring clotbur, 171 Spring sow-thistle, 169 Spurge family, 143 Spurry, 130 Squirrel-tail grass, 115 St. John's-wort family, 147 Star thistle, 163 Stellaria, 131 STER´ILE, not fertile. Stick-seed, 152 Stink grass, 115 Stipa spartea, 117 Stonecrop, mossy, 138 Stork's-bill, 142 STRI´ATE, striped with parallel ridges and grooves. Swallow-wort, 149 Swamp begger-ticks, 163 Sweet clover, 140 Sweet everlasting, 166 Syntherisma, 113 Tall buttercup, 131 Tall mustard, 137 Taraxacum, 170 Teasel family, 160 Thistle, 164 Thistle, Russian, 126 Thorn apple, 155 Three-seeded mercury, 143 Thyme-leaved sandwort, 129 Thyme-leaved speedwell, 157 Thyme-leaved spurge, 144 Toad-flax, 156 Tragopogon, 170 Treacle mustard, 135 Trefoil, 139 Trifolium, 141, 142