Chapter XII: Book II: is called ‘de Bulbosis,’ and a section of Book IV, including

eighteen genera, is headed ‘Umbelliferæ.’ Some of the sections represent truly natural groups. Book III, Section VI, for example, consists of ten genera of Compositæ, while Book III, Section II includes six Crucifers. Other sections contain plants of more than one family, but yet show a distinct feeling for relationship. For instance,