namely, how it is possible for the morphological affinity of species in the system to be in so high a degree independent of their physiological adaptation to their environment.
The modern teaching on vegetable cells, modern anatomy, and morphology, and the improved form of the theory of selection are the product of inductive enquiry since 1840, a product, the full importance of which will be described in the following portions of our history. At present we have to deal only with morphological and systematic results, and therefore with a part only of the abundant labours of the botanists who will be noticed in this chapter; the remainder will be reserved for succeeding books, which contain the history of the anatomy and physiology of plants.
It is one of the characteristic features of this period of botany, that morphology enters into the closest connection with the doctrine of the cell, with anatomy and embryology, and that researches, especially into the process of fecundation and the formation of the embryo, form to some extent the central point of morphological and systematic investigations. A strict separation of these various enquiries, which are all ultimately applicable to the purposes of systematic botany, can therefore scarcely be maintained, and least of all in dealing with the lower Cryptogams.
The condition of botanical literature about the year 1840 was highly unsatisfactory; it is true that eminent service was rendered in the several domains of systematic botany, morphology, anatomy, and physiology, and a number of von Mohl's best works were produced in this period; Meyen also, Dutrochet, Ludolph Treviranus and others were cultivating vegetable anatomy and physiology, and it has been already stated that good and noticeable work was done in the previous years in morphology and systematic botany. But there was no one to put together, to criticise and apply the knowledge
