Florets bilabiate.
The plants belonging to this division are rarely seen in British gardens; but when they do occur, they are well worth examining, from the singularity of their formation. Mutisialatifolia (see fig. 46) has a large, woolly involucre, the
Fig. 46.—Flower and Leaf of Mutisia Latifolia. scales of which are of two kinds, the outer ones, (a), being pointed and leaf-like, and the inner ones, (b), having the appearance of scaly bracts. The florets of the ray, (c), are narrow, and spreading in the fully expanded flower; and those of the disk, (d), are shorter, erect, divided into two lips, which curl back, and the lower one of which is again divided into two segments (as shown at e in the detached floret). The leaves of this plant are very curious; the midrib is lengthened and drawn out into a tendril, as shown at f, and the petiole (g) is decurrent. There are several other genera belonging to this tribe, but none of them are particularly ornamental except Triptilion spinosum, which has flowers of the most brilliant blue, that do not lose the intensity of their colour in drying.
CHAPTER VII.
THE ORDER ERICACEÆ: ILLUSTRATED BY THE COMMON OR BESOM HEATH, THE MOOR HEATH, CAPE HEATHS, LING OR HEATHER, ANDROMEDA, LYONIA, ST. DABÆOC’S HEATH, ARBUTUS, THE BEARBERRY, GAULTHERIA, CLETHRA, RHODODENDRON, INDIAN OR CHINESE AZALEAS, YELLOW AZALEA, AMERICAN AZALEAS, RHODORAK, ALMIA, MENZIESIA, LOISELEURIA, LEDUM, LEIOPHYLLUM, THE BILBERRY, THE WHORTLE-BERRY, THE CRANBERRY, PYROLA, AND MONOTROPA.
The name of Ericaceæ, which most people are aware signifies the Heath family, conjures up immediately the image of a number of narrow-leaved plants, with globular, ventricose, or bell-shaped flowers; and we are apt at first to think that the family is so natural a one, as to require very little explanation. Did the order include only the Heaths, this would be the case, for all the Heaths, different as they are in some particulars, may be recognised at a glance: but as the order includes the Rhododendrons, Azaleas, and Kalmias, besides several other plants which have not so strong a family likeness to each other as the Heaths, it becomes necessary to say a few words on the botanical resemblances which connect them together. The first, and most striking, of these is the shape of the anthers, each of which appears like two anthers stuck together, and the manner of their opening, which is always by a pore or round hole, in the upper extremity of each cell. The filaments, also, in all the genera, except Vaccinum and Oxycoccus, grow from beneath the seed-vessel, being generally slightly attached to the base of the corolla. There is always a single style with an undivided stigma, though the capsule has generally four cells, each containing several of the seeds, which are small and numerous. The calyx is four or five cleft, and the corolla is tubular, with a larger or smaller limb, which is also four or five cleft. The order has been divided into four tribes, which I shall describe in this chapter, though some of these are considered as separate orders by Dr. Lindley and other botanists.