=Various Forms of Corolla.=--The corolla often assumes very definite or distinct forms, especially when gamopetalous. It may have a long tube with a wide-flaring limb, when it is said to be =funnelform=, as in morning-glory and pumpkin. If the tube is very narrow and the limb stands at right angles to it, the corolla is =salverform=, as in phlox. If the tube is very short and the limb wide-spreading and nearly circular in outline, the corolla is =rotate= or =wheel-shaped=, as in potato. A gamopetalous corolla or gamosepalous calyx is often cleft in such way as to make two prominent parts. Such parts are said to be =lipped= or =labiate=. Each of the lips or lobes may be notched or toothed. In 5-membered flowers, the lower lip is usually 3-lobed and the upper one 2-lobed. Labiate flowers are characteristic of the mint family (Fig. 185), and the family therefore is called the Labiatæ. (Literally, labiate means merely “lipped,” without specifying the number of lips or lobes; but it is commonly used to designate 2-lipped flowers.) Strongly 2-parted polypetalous flowers may be said to be labiate; but the term is oftenest used for gamopetalous corollas. Labiate gamopetalous flowers that are closed in the throat (or entrance to the tube) are said to be grinning or =personate= (personate means _masked_, or _person-like_). Snap-dragon is a typical example; also toadflax or butter-and-eggs (Fig. 186), and many related plants. Personate flowers usually have definite relations to insect pollination. Observe how an insect forces his head into the closed throat of the toadflax. [Illustration: FIG. 186.--PERSONATE FLOWER OF TOADFLAX.] The peculiar flowers of the pea tribes are explained in Figs. 187, 188. [Illustration: FIG. 187.--FLOWERS OF THE COMMON BEAN, with one flower opened (_a_) to show the structure.] [Illustration: FIG. 188.--DIAGRAM OF ALFALFA FLOWER IN SECTION: _C_, calyx; _D_, standard; _W_, wing; _K_, keel; _T_, stamen-tube; _F_, filament of tenth stamen; _X_, stigma; _Y_, style; _O_, ovary; the dotted lines at _E_ show position of stamen tube, when pushed upward by insects. Enlarged.] =Spathe Flowers.=--In many plants, very simple (often naked) flowers are borne in dense, more or less fleshy spikes, and the spike is inclosed in or attended by a leaf, sometimes corolla-like, known as a =spathe=. The spike of flowers is technically known as a =spadix=. This type of flower is characteristic of the great arum family, which is chiefly tropical. The commonest wild representatives in the North are Jack-in-the-pulpit, or Indian turnip, and skunk cabbage. In the former the flowers are all diclinous and naked. In the skunk cabbage all the flowers are perfect and have four sepals. The common calla is a good example of this type of inflorescence. [Illustration: FIG. 189.--HEAD OF SUNFLOWER.]