sed on all sides, and not closely laid over each other, as in the preceding species. This last is the perianthium squarrosum, or squarrose calyx; of which we have examples in Thistle, Onopordum, Conyza, &c*. 3. In some plants, as in the Pink, Coreopsis, and others, the base of the calyx, which is simple, is surrounded, externally, by a series of distinct leaves, which are shorter than its own. To this species of calyx, Linnæus has given the name of calyx auctus, and Vaillant, calyx calyculatus, an increased calyx, caliculate, or calycled calyx. 4. The perianthium scariosum, or scariose perianth, is a species of calyx, which is tough, thin and semi-transparent; as in Statice Armeria, or Thrift, Centaurea glastifolia, &c. 5. The perianthium turbinatum,turbinate, or top-shaped perianth, is inversely conical, and shaped like a boy's top, or a pear. The Grislea secunda and Memecylon capitellatum exhibit instances of this species of perianth.

m. THE perianthium is either, 1. proprium, proper, that is belonging to one flower; or, 2. commune, common, belonging to several flowers, collected together.

n. Some flowers, such as the Amaryllis, the Tulip, the Lilyt, and many others of the liliaceous plants; also the Medeola‡, are said to be destitute of the perianth. But I shall afterwards have occasion to observe, that what the Swedish naturalist names, in these flowers, the corolla is deemed the calyx, by some other eminent botanists.

See the Plate of Helianthus divaricatus.

† See Plate XIII. Fig. 2.

See Plate XIV.

In the greater number of plants, the perianth is single. In Morina, Sarracenia* and some of the plants of the Mallow-family, as Althæa, Alcea, Malva, Lavatera, Gossypium, Hibiscus, &c. it is double.

SEVERAL circumstances relative to the perianth are necessarily delayed, until I shall have entered on the consideration of the corolla. Of the real and supposed uses of the perianth, I shall treat, after having finished the history of the various species of calyx. I have already mentioned the marks, or characters, by which the perianth may be distinguished from the bractes.

2. THE second species of calyx, which I have mentioned, is the Involucrum‡. This is called by Dr. Martyn, Involucre. It is chiefly restricted by Linnæus to the umbelliferous flowers, and is defined, by this writer, a calyx remote from the flower**.

THIS species of calyx is placed below the common receptacle, which, in the umbelliferous plants, is a number of footstalks, which all proceed from one common point or centre, and rise to the same height. Each of the footstalks is terminated by an umbel, which is similar, in its form and structure, to the large umbel, and is commonly, like it, furnished with an involucre. When a calyx of this kind is placed under the universal umbel, it is called, by Linnæus, involucrum universale, an universal involucre. When it is placed under the smaller or

partial umbel, it is denominated involucrum partiale, a partial involucre. This is sometimes termed, involucellum, or involucret. Dr Withering calls it the Partial Fence.

In most of the umbelliferous flowers, such as the Hemlock, Fennel, Anise, and in other plants, not strictly umbelliferous, as the Cornus florida, or Dogwood, and other species of this genus, there is, besides the two involucres, a proper perianth, which is situated under each of the florets, or smaller flowers, of which the umbel is composed.

THE involucre is composed of one or more leaves. When composed of one, it is denominated involucrum monophyllum, a one-leafed involucre, as in Bupleurum: when of two leaves, involucrum diphyllum, a two-leafed involucre, as in Euphorbia: when of three, involucrum triphyllum, as in Butomus and Alisma: when of four, involucrum tetraphyllum; as in Cornus: when of five, involucrum pentaphyllum; as in Daucus; and when of six, involucrum hexaphyllum; as in Hemanthus.

THE partial involucre, or involucret, consists either of two leaves, as in Artedia; of five, as in Hare's ear; or of many, as in Bishop's-weed, and Fennel. Giant.

THE involucrum dimidiatum, dimidiate, or halfleaved involucre, is an involucre which is deficient on one side; as in Æthusa, or Fools Parsley.

It is difficult to say, in what very essential circumstance the involucre of those plants which are not umbelliferous, such as Cornus, or Dogwood, some species

of Anemone, &c. differs from the bractea, or bracte. It would seem, indeed, that Linnæus's principal reason for separating the involucre from the bracte was this, that he might make use of the former part in drawing his generic characters of the umbelliferæ.

3. THE Amentum*, or Ament, called also Catkin, is a species of calyx, which consists of a great number of chaffy scales, that are dispersed along a slender thread, or receptacle. On account of its supposed resemblance to a cat's tail (though it bears as close a resemblance to the tails of many other animals as to that of the cat), it has received one of its English names, viz. catkin. The French call it Chaton; and many botanists have denominated it Catulus. The term amentum was used by the great Tournefort, before it was employed by Linnæus. The term is perfectly synonimous to the terms julus and nucamentum, which are employed by some botanists.

LINNEUS defines the ament to be a composition of a calyx, and a common receptacle. The squamæ, or scales, which form this species of calyx, are mixed alternately with the flowers, and resemble the chaff in an ear of cornt.

THE ament occurs very frequently in the xxIst and XXIId classes of the Sexual System, the classes Monoecia and Dioecia, the particular characters of which are

The term amentum, as used by the Roman writers, signifies a thong, a loop,

a strap, or lash, to hold a sling, spear, or javelin by.

† For a fine representation of the ament, see the figure of Betula populifolia, in this work.

afterwards to be explained*. In this place, however, it is proper to observe, that in the first mentioned class, the ament supports both male and female flowers, on the same root, or individual. This is the case in the Hornbeam, Walnuts, and Hickeries, Chesnut, Chinquepin, and many others. In the class Dioecia, the ament supports male and female flowers, on distinct roots, or individuals. This is the case in the Willows, Poplars, and many others.

Ir not unfrequently happens, that in plants of the class Monoecia, the male and female flowers are mixed together, or situated very close to each other; whilst in other plants, they are situated at a considerable distance from each other; but, in both instances, upon the same root, or individual.

In the latter case, the ament frequently supports flowers of one sex, and a calyx of the perianth-kind supports those of another sex. Thus, in the Corylus, or Hazle, the male and female flowers are placed remote from each other, upon the same root, or individual. The male flowers form an ament, whilst the females are inclosed in a perianth.

IN the class Dioecia, there are some plants, such as Pistachia-nut, Juniper-tree, and Ephedra, or Shrubby Horse-tail, the male flowers of which are formed into an ament; whilst the female flowers are surrounded with a perianth.

In general, those flowers, whether they be male, or female, or both, which are supported by an ament, are

* See Part 1II.