Order 6. Frankeniaceæ. A small order with doubtful relationships. Perennial herbs or shrubs; beach plants with nodose stem. Sepals united, petals free. Unilocular ovary, with 3–4 parietal placentæ. Fruit a capsule. Embryo straight, endospermous. Especially in S. Europe, Africa, on the shores of the Mediterranean and Atlantic.
Order 7. Tamaricaceæ (Tamarisks). To this order belong only Tamarix and Myricaria. They are shrubs of a cypress- or heather-like appearance, as the scattered leaves are very small, sessile, scale-like or linear, adpressed, entire, and usually glaucous, and the branches are slender and whip-like. The flowers are borne in small spikes or racemes, and are small, reddish or whitish, regular, ☿, hypogynous and polypetalous; formula S5, P5, A5 + 0 (Tamarix, which often has stipular teeth at the base of the filaments), or A5 + 5 (Myricaria, in which the stamens are united at the base); the number 4 may appear instead of 5, but in either case there is usually a tricarpellate gynœceum, which is unilocular and has either parietal placentæ (Myricaria) or a small basal placenta (Tamarix); 1 trifid style, or 3 styles. Capsule dehiscing along the dorsal suture, and resembling the Willows in having a unilocular ovary with numerous woolly seeds; but the seed-wool in this case is borne on the chalaza, and may be attached to a long stalk.—Some Tamarix-species shed part of their branches in the winter.—40 species; North Temperate, on the sea-shores or steppes, especially in Asia. Ornamental shrubs: Myricaria germanica, and Tamarix gallica.
Order 8. Cistaceæ. Shrubs or herbs, natives especially of the Mediterranean region. Flowers generally in raceme-like scorpioid cymes, regular, ☿, hypogynous; sepals 5, free, twisted in the bud, of which the two outer are generally much smaller than the others; petals 5, free, twisted in the bud (in the direction opposite to the sepals), fugacious; stamens numerous; gynœceum syncarpous, carpels usually 3–5, style simple, ovary unilocular, with parietal placentation (seldom divided into loculi, with axile placentation). The ovules are orthotropous in opposition to some of the other orders of this family. The capsule dehisces along the dorsal sutures; embyro curved. The leaves are simple, undivided, generally opposite and stipulate.—They are Violaceæ with regular flowers, numerous stamens, and curved embryo. The numerous stamens are in reality only one or two 5-merous whorls, divided into a large number of stamens; these are formed, therefore, in descending order, like the lobes of many compound foliage-leaves.
Helianthemum (Rock-Rose), has 3 carpels.—Cistus has 5 (-10) carpels.
About 70 species; temperate climates, especially about the Mediterranean. The resin of the Cistus-species has been used medicinally (ladanum).
Order 9. Bixaceæ. This order is closely allied to the Cistaceæ and Ternstrœmiaceæ; like these it has regular, 5-merous, hypogynous flowers with numerous stamens, unilocular ovary and parietal placentæ; sometimes unisexual flowers; it differs in having anatropous ovules, in the æstivation of the sepals, etc. All species (about 180) are trees or shrubs, with scattered, simple leaves, which usually have stipules, and are occasionally dotted with pellucid oil-glands.—Bixa orellana (Trop. Am.) is the best known species; it has a 2-valved capsule; the seeds are enclosed in a shiny red, fleshy testa, which contains the well-known orange or yellow dye, annatto.
Order 10. Dilleniaceæ. Gynœceum usually apocarpous, seed arillate. The flower has most frequently S5, P5, and compound stamens (one or more bundles); sometimes irregular. 200 species; Tropical; woody plants, many lianes.—Dillenia, Candollea, Pleurandra, Davilla, etc.
Order 11. Elatinaceæ (Water-worts). About 25 species belong to this order; especially in temperate climates. They are small, creeping, rooted, aquatic plants, with opposite or verticillate leaves and stipules. The flowers are solitary or situated in small dichasia in the leaf-axils, they are small, regular, ☿, hypogynous, with free petals, the same number in all 5 whorls (Sn, Pn, An + n, Gn), 3-merous (e.g. Elatine hexandra), 4-merous (e.g. E. hydropiper), or 5-merous (Bergia); the corolla-stamens are sometimes suppressed; petals imbricate without being twisted; the ovary is 3–4–5-locular, with 3–4–5 free styles; the capsule dehisces septicidally. The seeds are orthotropous or curved, often transversely ribbed, endosperm wanting. The order is most nearly allied to Hypericaceæ, whose primitive form it appears to represent.
Fig. 426.—Diagram of Hypericum quadrangulum: S indicates the bud of the helicoid cyme in the axil of the bracteole β.