Page:An introduction to physiological and systematical botany (1st edition).djvu/532

 502 Persoon has been commendably sparing of new terms. Besides hymenium above explained, he has scarcely introduced any other than peridium, for the round membranous dry case of the seeds in some of the 1st section. The term pileus, a hat, is used by all authors for the head of those fungi that compose the 2d section.

. Palmæ. The natural order of Palms was so little understood when Linnæus formed his systematical arrangement of plants, and so few of their flowers had been scientifically examined, that he was under the necessity of leaving this order as an appendix to his system, till it could be better investigated. To its peculiar habit and physiology we have adverted in several of the foregoing pages, see p. 57—59, 62, 133, &c.

Late observations show Palms to have for the most part 6 stamens, rarely 3 or 9, with 3 or 6 petals, and 1 or 3 styles; which last are sometimes in the same flower with the stamens, sometimes in a separate one, but both flowers always agree in general structure. Their fruit is generally a drupa. They