_Primulaceæ_--Primrose family. All herbs in which the stamens are as many as the lobes of the corolla and inserted on them. The flowers are quite regular. They all have some form of a capsule for fruit, which in most generally split lengthwise. Familiar examples include the garden primrose (not the wild evening primrose), yellow loosestrife, the star flower, pimpernel, shooting star, and the beautiful cyclamens. A few members of the family are slightly luminous in the dark, apparently an attraction to night-flying insects. About 28 genera and over 400 species, mostly from the northern hemisphere, a few in temperate South America and South Africa. _Gentianaceæ_--Gentian family. Over 700 species in 70 genera, all bitter herbs, with opposite leaves, quite without teeth and beautiful, sometimes fringed, always regular flowers. In this and related families the stamens are of the same number as the lobes of the corolla, and always alternate with them. Gentian and sea or marsh pinks are our best-known native representatives, while some related plants are medicinal. There are many other families in this part of the scheme of plant classification that have minor differences among themselves, but agree pretty generally in the number and position of their stamens, their superior ovary, and, on the whole, in the regular flower. Irregular and regular flowers may be recognized at once by cutting them lengthwise through the middle. In regular flowers there would be as much on one side as on the other of the dividing line, and in irregular ones quite obviously more on one side than the other. The character of all the genera in a family having irregular flowers begins to occur here with greater and sometimes exclusive frequency. In the mint family, or Lamiaceæ, nearly all of its 160 genera and over 3,000 species have two-lipped or irregular flowers. The garden salvia well illustrates the type. The _Lamiaceæ_ or Labiatæ, as they are often called from the two-lipped corolla, are herbs locally, but in the tropics often shrubs or trees. Almost universally they have four-sided stems and opposite leaves without stipules. The flowers may be solitary, much more often they are crowded into various kinds of clusters. The four stamens are borne on the corolla tube, and nearly always there are two long and two short ones. The family is universally fertilized by insects, and some of the flowers are wonderfully adapted for this end. Common examples, besides the salvia, are mint, thyme, skullcap, hyssop, bugle, blue curls, catnip, hedge-nettle, coleus, and Oswego tea. Most of the genera contain heavy odorous oils in their foliage, from which oil of mint, pennyroyal, lavender, rosemary, marjoram, savory and balm are the best known. These volatile oils give to members of the family their characteristic and often very beautiful odors.