Cross-section of pink root 219 Cross-section of ruellia root 219 Cross-section of spigelia rhizome 223 Cross-section of ruellia rhizome 226 Powdered pink root 227 Powdered ruellia root 227 CHAPTER II STEMS Herbaceous stems 233 Cross-section, spigelia stem 233 Ruellia stem 235 Powdered horehound 237 Powdered spurious horehound 237 Insect flower stems 241 CHAPTER III WOODY STEMS Buchu stem 242 Mature buchu stem 242 Powdered buchu stem 245 CHAPTER IV BARKS White pine bark 248 Powdered white pine bark 250 CHAPTER V WOODS Cross-section quassia 254 Radial-section quassia 254 Tangential-section quassia 258 CHAPTER VI LEAVES Klip buchu 260 Powdered klip buchu 262 Mountain laurel 264 Trailing arbutus 264 CHAPTER VII FLOWERS Pollen grains 270 Non-spiny-walled pollen grains 273 Spiny-walled pollen grains 273 Stigma papillæ 274 Powdered insect flowers 278 Open insect flowers 280 Powdered white daisies 282 CHAPTER VIII FRUITS Celery fruit 285 CHAPTER IX SEEDS