M. Puel[19] describes a leaf of _Polygonatum multiflorum_, the margins of which were so completely united together, as only to leave a circular aperture at the top, through which passed the ends of the leaves. The Rev. Mr. Hincks, at the meeting of the British Association at Newcastle (1838), showed a leaf of a Tulip, whose margins were so united that the whole leaf served as a hood, and was carried upwards by the growing flower like the calyptra of a Moss. The margins of the stipules are also occasionally united, so as to form a little horn-shaped tube. I have met with instances of this kind in the common white clover, _Trifolium repens_, where on each side of the base of the petiole the stipules had the form just indicated. That the bracts also may assume this condition, may be inferred from the peculiar horn-like structures of _Marcgraavia_, which appear to originate from the union of the margins of the reflected leaf. =Tubular petals= occur normally in some flowers, as _Helleborus_, _Epimedium_, _Viola_, &c., and as an exceptional occurrence I have seen them in _Ranunculus repens_, while in _Eranthis hyemalis_ transitions may frequently be seen between the flat outer segments of the perianth and the tubular petals. To Dr. Sankey, of Sandywell Park, I am indebted for the flower of a Pelargonium, in which one of the petals had the form of a cup supported on a long stalk. This cup-shaped organ was placed at the back of the flower, and had the dark colour proper to the petals in that situation. I have seen a petal of Clarkia similarly tubular, while some of the cultivated varieties of _Primula sinensis_ exhibit tubular petals so perfect in shape as closely to resemble perfect corollas. [Illustration: FIG. 9.--_Eranthis hyemalis_. Transition from flat sepal to tubular petal.] Like the petals, the stamens, and even the styles, assume a hollow tubular form. This change of form in the case of the stamens is, of course, usually attended by the petaloid expansion of the filament, or anther, and the more or less complete obliteration of the pollen sacs, as in Fuchsias, and in some double-flowered Antirrhinums.[20] So also in some semi-double varieties of _Narcissus poeticus_, and in _Aquilegia_. By the late Professor Charles Morren, this affection of the stamens and pistils was called _Solenaidie_,[21] but as a similar condition exists in other organs, it hardly seems worth while to adopt a special term for the phenomenon, as it presents itself in one set of organs.