* Cardans nutans - Plate 15 A.
These flowers consist of a calyx adherent to the ovary, and having five narrow spreading lobes; a regular bell-shaped five-lobed corolla, inserted within the lobes of the calyx; five stamens with distinct anthers, inserted within the base of the corolla but free from it; and a style cleft at the top into two or three stigmatic lobes. The capsule, which is of course inferior, is pendulous, and opens by short clefts near its base. It is a really elegant little plant.
* Campanula rotundifolia - Plate 15 B.
The family of Ericaceous plants, represented by what Mr. Bentham calls the Scotch Heath,* is another Monopetalous group in which the stamens are free from the corolla, but in this case they are hypogynous. This very common and very beautiful plant, though it has been distinguished as the Scotch Heath, is by no means confined to that country, but ranges over the whole of Britain, and is common in Western Europe, covering immense tracts of moorland, which in the flowering season are sheeted with the rich purple of the heather-bells. It is a dwarf bushy shrub, of about a foot in height, clothed with fine linear leaves which are usually set three in a whorl, with clusters of smaller leaves in their axils. The flowers are numerous, in dense terminal elongated whorled racemes, and are furnished with a calyx of four small sepals; an ovoid corolla, with a contracted mouth, and four very small lobes or teeth; eight stamens enclosed in the corolla, and remarkable for their opening by two pores at the top, and also for having a small toothed appendage at the point where the anthers are joined to the filament; and a long style thickened at the stigmatic end. The fruit is a free four-celled capsule. It will be observed that the Heaths are plants in which the parts of the flower are made up in fours or in multiples of four; hence they belong to what are called tetramerous plants, those in which the parts are governed by the more usual number, five, being called pentamerous. It has already been pointed out that in the great group of Monocotyledons the number three is that which governs the part of the flowers.
* Erica cinerea - Plate 15 C.
We now come to a group of perigynous Monopetals in which the corolla is nearly or quite regular, and is moreover attached beneath the ovary. It is the perigynous condition of the flowers, the corolla bearing the stamens, which constitutes the chief technical distinction between these and the hy-pogynous-flowered Heaths previously described.
Of these, the Common Privet,* a member of the Oleaceous or Olive family, though by some referred to the Jasmines, is an example. This well-known shrub, employed in gardens in making hedges, and as an undergrowth in shrubberies, is found wild in hedgerows and thickets in the southern parts of England. It is a subevergreen shrub, of six or eight feet high, with long slender branches, which bear opposite lance-shaped leaves, and are terminated by short compact panicles of flowers, consisting of a small four-toothed calyx, a four-lobed short-tubed corolla, and a pair of short stamens. The flowers are succeeded by blackish globular berries, which are two-celled, with one or two seeds in each cell. The Ash is a somewhat anomalous member of the same family, wanting both calyx and corolla in the flowers of our native species, but yielding in some exotic kinds flowers which have a four-lobed calyx and corolla. The Lilac is another well-known cultivated plant of the same group.
The Gentianaceous family, already referred to, is another of these perigynous Orders, with the stamens growing directly on the corolla. Of this family we have another illustration in an aquatic plant found in ponds and still waters in many habitats, known under the name of Nymphaea-like Villarsia, † or sometimes under that of Limnanthemum nymphceoides, the Common Limnanth. This is a perennial plant, with long slender stems, which creep and root at the base, and becoming branched rise to the surface of the water. They bear a single leaf at each upper branch, and a terminal floating tuft of leaves and flowers. The leaves are long-stalked, and are smooth, roundish, deeply cordate, lying on the water's surface like those of the Water Lily, of which they are miniatures. The flowers grow several from the tuft, and are just elevated above the water. They are rather large, yellow, consisting of a five-cleft calyx; a nearly rotate (that is, short-tubed and spreading, so as to become wheel-like) plaited corolla, slightly fringed at the base within, and finely toothed round the margin; five stamens; and a five-cleft stigma. The capsule breaks open unequally, not having any regular valves.
* Ligustrum vulgare - Plate 15 D. † Villarsia nymphceoides - Plate 16 A.
The Greek Valerian, or Jacob's Ladder,* belongs to the same series, and represents the Polemoniaceous family, better known in gardens by the fine hardy herbaceous genus Phlox, and the annual Gilia. The Greek Valerian, common in cottage gardens, and found in some places apparently wild, is a perennial herb, producing at the base tufts of leaves, which are pinnate or divided into separate leaflets or little leaves, from eleven to twenty-one in number, of a lance-shaped figure, and quite entire. These leaves are what are called impari-pinnate, that is to say, pinnate with the leaflets in opposite pairs along the sides, and having an odd terminal one. The flower-stems, in vigorous plants reaching two feet in height, bear a few small pinnate leaves, and terminate in a kind of corymbose panicle of showy blue flowers, which have a five-lobed calyx, a regular rotate five-lobed purplish-blue corolla, five stamens, the filaments of which are dilated into hairy scales, and a simple style with three stigmatic lobes or stigmas. The fruit is a three-celled capsule, containing many seeds. This is a very widely diffused plant, being scattered "over the higher northern latitudes of Europe, Asia, and America, extending also into the mountain regions of central Europe and Asia."