Fig. 515.—Passiflora cœrulea (reduced).
Order 1. Passifloraceæ (Passion-flowers). The majority are herbs which climb by means of tendrils (modified branches) and have scattered, stipulate leaves, often palminerved and lobed (Fig. [515]). The flowers, which are often large and beautiful, are regular, ☿, with S5, P5, A5, G3; the calyx and corolla are perigynous, and immediately inside the corolla is the “corona,” consisting of numerous, tapering, filamentous bodies, or sometimes united in rings, most frequently petaloid and coloured; the stamens are raised on a long, round internode above the cup-like receptacle; immediately above these is the gynœceum with its 3 free styles and capitate stigmas; the ovary is unilocular with 3 parietal placentæ. Fruit most frequently a berry. The seeds have an aril.
210 species; especially in Tropical America. Several Passiflora-species are ornamental plants, and the fruits of some species are edible.
Order 2. Papayaceæ. The best known representative is the Papaw (Carica papaya), a Tropical American tree whose stem is usually unbranched, and bears at its summit several large, palmilobed leaves on long stalks. The stem and leaves have latex. The large, Melon-like berries are edible, and for this reason it is cultivated in the Tropics. Flowers unisexual, with slightly different structure in the ♂-and ♀-flowers, besides intermediate forms. The ♂-flower has a gamopetalous, the ♀-flower a polypetalous corolla.—The milky juice contains a substance with similar action to pepsine. 10 stamens. 5 carpels.
Order 3. Turneraceæ. 85 species; especially in America.
Order 4. Samydaceæ. 160 species; tropical.
Order 5. Loasaceæ. Herbaceous plants seldom shrubs, sometimes climbing, and nearly always studded with stiff hairs, in some instances stinging or hooked. The leaves are most frequently palmilobed and without stipules. The flowers are regular, ☿, polypetalous, entirely epigynous, with 4–5 sepals, petals and stamens, or more frequently (by splitting) many stamens, those which are placed before the sepals being generally barren and more or less petaloid; carpels most frequently 3, united into an inferior, unilocular ovary with 3 parietal placentæ, above which the receptacle is generally more or less prolonged. Fruit a capsule; in Gronovia an ovary with 1 ovule and fruit a nut.
115 species; principally from S. Am. A number of annuals are often grown in our gardens: Bartonia aurea (California); Mentzelia; Cajophora; Gronovia.
Order 6. Datiscaceæ. 4 species, especially in the Tropics.—Datisca cannabina (Asia Minor) resembles the Hemp in external appearance. The flowers are diœcious, insignificant; ♂-flowers: a low, gamosepalous calyx, no corolla, and an indefinite number of stamens; ♀-flowers; epigynous; ovary unilocular with free, mostly bifid, styles, and generally 3 parietal placentæ. In most cases the ovary is not entirely closed at the top (as in Reseda).