Nierembergia is a genus of ornamental greenhouse plants, easily distinguished from the Petunias by the great length of the tube of the corolla, and by the equal segments of the limb. The stamens also project beyond the flower, being inserted in the throat of the corolla, and the filaments grow together at the base; the stigma, is, likewise, curiously dilated into a kind of crescent shape, and it is folded in a very singular manner round the filaments, as if to support the anthers. The most common species of this genus are N. filicaulis, N. calycina, and N. gracilis.
The genus Salpiglossis is now confined to one species, S. sinuata, so called from its notched or scolloped leaves; all the different kinds being now considered only varieties. The calyx in this species is five-angled and five-cleft, and the corolla is funnel-shaped, the tube being very narrow near the base, and spreading out wider towards the mouth. The limb is five-cleft, and there are five stamens, one being much smaller than the others. The stigma is transverse, with a channel through the centre.
Schizanthus is another genus nearly allied to the last, but it is more difficult to give a just idea of it than of any other that I have attempted to describe. All the parts of the flower are irregular. The segments of the calyx are uneven; and the limb of the corolla is cut into a number of irregular lobes. There are only two perfect stamens, but there are two other small ones without any pollen in their anthers, and the rudiments of a fifth. The two perfect stamens are very elastic, springing upwards and discharging their pollen at the slightest touch. The capsule is two-celled, the valves opening at top; and the leaves are bi-pinnatifid.
The genera Salpiglossis and Schizanthus have been removed by Dr. Lindley from Solanaceæ, and placed by him in the allied order Scrophularinaceæ, or the Foxglove family.
The Henbane (Hyoscyamus niger) has the calyx ventricose at the base, and the corolla campanulately funnel-shaped; the limb is five-cleft, and one of the segments is larger than the rest; but the most remarkable part of this plant
Fig. 71.—Henbane. is the capsule. When the corolla falls, the capsule shrouded in the calyx presents the appearance shown at a in fig. 71; and as the seeds ripen, the upper part (as shown at b) becomes detached, and opens like a little cap. The leaves are sinuated and semi-decurrent. There are several species of Henbane, one of which (H. aurea) has the limb of the corolla deeply cut on only one side.
The genus Datura is nearly allied to Brugmansia, but it may be easily distinguished by its calyx, which divides when the ovary begins to swell, and the upper part drops off, leaving only the lower part to enfold the capsule. The corolla of all the species of Datura is funnel-shaped, and the limb, in the large-flowered kinds, often shows marks of the plaits in which it lay when it was folded in the bud. There are five distinct stamens, which are generally enclosed in the mouth of the corolla. The capsule is fleshy when young, and in most of the species it is covered with spines. This is the case with D. Stramonium (the common Thorn-apple), D. Tatula, and D. Metel, all of which have also their stamens enclosed; but in D. ceratocaulon the capsule is smooth and the stamens exserted, that is, they project beyond the tube of the corolla.
The genus Brugmansia is distinguished by its calyx being ventricose, and only two or three cleft; it is also strongly ribbed. The corolla is funnel-shaped, the tube being strongly ribbed; and the limb is five-lobed, the lobes being cuspidate, that is, drawn out into abrupt points. The flowers are drooping, and in Brugmansia suaveolens, formerly Datura arborea, they are very fragrant. The anthers grow together. The capsule is two-celled, smooth, and of a golden yellow, and the seeds are each covered with a thick corky skin. In Solandra, a nearly allied genus, the calyx bursts on one side, and the lobes of the corolla are not cuspidate, but rounded and fringed. The stamens also project beyond the mouth of the corolla, and the capsule is four-celled. The species of Solandra are all stove-trees.