Page:An introduction to physiological and systematical botany (1st edition).djvu/537

 Rh preserved. Even in spreading plants between papers, we should refrain from that precise and artificial disposition of their branches, leaves, and other parts, which takes away from their natural aspect, except for the purpose of displaying the internal parts of some one or two of their flowers, for ready observation.

After all we can do, plants dry very variously. The blue colours of their flowers generally fade, nor are reds always permanent. Yellows are much more so, but very few white flowers retain their natural aspect. The Snowdrop and Parnassia, if well dried, continue white. Some greens are much more permanent than others; for there are some natural families whose leaves as well as flowers turn almost black by drying, as Melampyrum, Bartsia, and their allies, several Willows, and most of the Orchideæ. The Heaths and Firs in general cast off their leaves between papers, which appears to be an effort of the living principle, for it is prevented by immersion of the fresh specimen in boiling water. Nandina domestica, a Japanese shrub, lately introduced among us by Lady