A plant of the lily family (Liliaceæ). Note the tendency to net-veined leaves in a monocotyledonous plant. Such instances are common in nature and net-veined leaves are found in certain species of smilax and most of the plants of the Arum family, containing the jack-in-the-pulpit, both monocotyledons.
Much more highly developed than the grasses is the lily family or Liliaceæ ([Figure 88]), but comprising less than 1,500 species in about 125 genera. They are nearly always herbs, but the Spanish bayonet forms a woody trunk, while the dragon tree of the Canary Islands is an extraordinary plant for a lily relative, one giant specimen of this being 80 feet tall and over 45 feet in circumference.[1] The flowers in the Liliaceæ are nearly always perfect, that is, stamens and pistils are found in the same flower. Its perianth segments are nearly always six, sometimes distinguishable as petals and sepals, but more often, as in the tulip, all colored similarly. The fruits are practically always a capsule that splits lengthwise. Perhaps the different plants in the Liliaceæ, as well as any others, illustrate the fact that plants of any particular family need not look like one another in order to be included in the same family. Nothing could be farther from resemblance than the bulb-bearing onion, the tulip, the Easter lily, the Spanish bayonet, and the dragon tree. Yet they and hundreds of other plants belong to the Liliaceæ. It cannot be overemphasized that it is flower and fruit characters that determine inclusion in any plant family, and similarity of leaves or habit may or may not accompany such characters. Among other well-known plants in the family, which is found throughout the world, are the crocus, the day lily, the dogtooth violet, hyacinth, and colchicum and aloes used in medicine. Many of them produce bulbs, such as onion, tulip, and lily and some of these contain valuable foods and drugs. The great majority of them are insect fertilized and are therefore wonderfully colored, and some furnish rich stores of honey.
But the most highly developed and interesting of all the monocotyledonous plants are the orchids ([Figures 89-92]). This family, Orchidaceæ,