The second order of the monocotyledons, _Enantioblastæ_, includes very few common plants. The most familiar examples are the various species of _Tradescantia_ (Fig. 88), some of which are native, others exotic. Of the cultivated forms the commonest is one sometimes called "wandering-jew," a trailing plant with zigzag stems, and oval, pointed leaves forming a sheath about each joint. Another common one is the spiderwort already referred to. In this the leaves are long and pointed, but also sheathing at the base. When the flowers are showy, as in these, the sepals and petals are different, the former being green. The flowers usually open but once, and the petals shrivel up as the flower fades. There are four families of the order, the spiderwort belonging to the highest one, _Commelyneæ_. ORDER III.--_Spadicifloræ_. The third order of the monocotyledons, _Spadicifloræ_, is a very large one, and includes the largest and the smallest plants of the whole sub-class. In all of them the flowers are small and often very inconspicuous; usually, though not always, the male and female flowers are separate, and often on different plants. The smallest members of the group are little aquatics, scarcely visible to the naked eye, and of extremely simple structure, but nevertheless these little plants produce true flowers. In marked contrast to these are the palms, some of which reach a height of thirty metres or more. The flowers in most of the order are small and inconspicuous, but aggregated on a spike (spadix) which may be of very large size. Good types of the order are the various aroids (_Aroideæ_), of which the calla (_Richardia_) is a very familiar cultivated example. Of wild forms the sweet-flag (_Acorus_), Jack-in-the-pulpit (_Arisæma_) (Fig. 86, _A_, _D_), skunk-cabbage (_Symplocarpus_), and wild calla may be noted. In _Arisæma_ (Fig. 86, _A_) the flowers are borne only on the base of the spadix, and the plant is diœcious. The flowers are of the simplest structure, the female consisting of a single carpel, and the male of four stamens (_C_, _D_). While the individual flowers are destitute of a perigone, the whole inflorescence (cluster of flowers) is surrounded by a large leaf (spathe), which sometimes is brilliantly colored, this serving to attract insects. The leaves of the aroids are generally large and sometimes compound, the only instance of true compound leaves among the monocotyledons (Fig. 86, _B_).