It was these metamorphic forms of the free portion of the calicinal foliola (united below) of the rose, which originated a well-known enigma, conveyed in the following Latin distich:-- "Quique sumus fratres, unus barbatus et alter, Imberbes duo, sum semi-berbes duo, sum semi-berbes ego." ("We are brothers, both bearded, two beardless; I am two half-bearded, and I myself am half-bearded.") They are specially noticeable in a variety of the Rose of Bengal, in which all the petals seem to be transformed into calicinal leaves. (Fig. 44.) * * * * * The part of the calyx formed by the union of the sepals is called the _tube_: it is invariably the lower part. The upper portion, where the sepals are free, is the _limb_. Throughout the vegetable kingdom you will not find a calyx in which the union of the sepals takes place at the top. This time, at all events, we have found--what is exclusively rare in nature--a rule without an exception. Generally, it is almost impossible to disunite, without rending, the foliola composing the tube of the calyx, their union is so complete. This circumstance prevented the first observers from accurately apprehending the composition and true development of the calyx. There are cases, nevertheless, in which Nature--the coquette!--suffers herself to be surprised, if her lover have patience. As an example we shall cite the monophyllous calyx of the Œnotheræ. [Illustration: FIG. 44.--Rose of Bengal.] Let us take the species known as _Œnothera biennis_. It belongs, with the fuchsia, circæa, trapa, and others, to the Evening Primrose family, or Onograceæ. Its pale yellow blossoms are unfolded during the hush of evening-time in almost every garden, shedding abroad on the breeze its delicate but delicious odour. Its petals open in a remarkable manner. The calyx, as we shall see, has small hooks attached to its upper extremity, by which it holds the flower together before expansion. The calicinal divisions gradually unfold at the lower part, and reveal the yellow flower, which remains awhile closed at the upper parts of the hooks. The flower then suddenly opens half-way, when it stops; afterwards completing its expansion gradually, and finally opening with a loud noise. This curious plant is of American origin, and was unknown in our country until 1674, when it was introduced by some French floriculturists. It opens generally at about six or seven o'clock in the evening. And this statement induces me to digress. Where can I better introduce to the reader's notice a Floral Dial? It is not so complete as it might be made if I had space to enlarge upon the subject. My object, however, is simply to _suggest_; and this brief allusion to the hours at which flowers fold and unfold may induce the reader to study in more detail a very pleasant branch of botanical science. He will find full particulars in Mr Loudon's excellent "Encyclopædia of Gardening."