Page:An introduction to physiological and systematical botany (1st edition).djvu/275

 Rh their urn-shaped base; the two green bristly ones which enfold the bud in Glaucium luteum, Fl. Brit. Engl. Bot. t. 8; the tubular part, comprehending the scales at its base, in the Pinks, t. 61, 62, or the globular scale cup in Centaurea, t. 56. The Tulip, t. 63, is a naked flower, having no calyx at all.

This part is of an infinite variety of forms in different genera, being either simple or compound, divided or undivided, regular or irregular. In some instances it is permanent till the fruit is ripe, in others it falls even before the flower is well expanded.

Some genera have a double perianthium, as Malva, t. 671, or even a triple one, as Scabiosa, t. 1311.

2. Involucrum. Involucre of Professor Martyn; but I generally retain the Latin termination. This is remote from the flower, and can scarcely be distinguished from a Bractea. The term was first adopted by Linnæus, at the suggestion of his friend Artedi, in order to distinguish