Primula (Primrose) has most frequently a vertical rhizome, bearing a rosette of leaves at its summit, and long-stalked umbels; corolla rotate or slightly funnel-shaped; the capsule opens at the apex by 5 teeth. The flowers in some species are heterostyled (long-styled or short-styled; Fig. [548]). Closely allied are Androsace (with ovate, cup-shaped corolla-tube and ligular scales, alternating with the corolla-lobes) and Soldanella (funnel-shaped corolla with laciniate lobes and most frequently ligular scales).—Hottonia (Water-Violet) is an aquatic plant with pectinate leaves and heterostyled flowers.—Cortusa. Dodecatheon. Cyclamen (Fig. [549]) has solitary, long-stalked flowers, and a rotate corolla with the lobes reflexed; the stalk of the capsule rolls up spirally; the tuberous rhizome is formed by the hypocotyledonary internode. Only 1 cotyledon.—Lysimachia (Money-wort); stem-internodes well developed, leaves opposite or verticillate, calyx almost polysepalous, corolla deeply 5-partite (Fig. [550]). The flowers are solitary or in racemes.—Anagallis (Pimpernel), leaves opposite, flowers solitary; the fruit a pyxidium (Fig. [551]); similarly in Centunculus, which is 4-merous.—Trientalis, the flowers are most frequently 7-merous.—Glaux (Sea Milk-wort) is a creeping maritime plant with opposite leaves; flowers solitary in the leaf-axils, corolla absent, but with coloured calyx. The petals are usually developed later than the stamens in the Primulaceæ; but in this instance they are entirely suppressed.—Samolus (Brookweed) differs from all the others in having an epigynous flower; barren sepal-stamens are also present. The bracts in the racemose inflorescences are displaced along the flower-stalks.
Fig. 550.—Lysimachia thyrsiflora.
Fig. 551.—Anagallis arvensis. Fruit dehiscing.
Pollination. Insect-pollination in the majority; cross-pollination is promoted in some by heterostyly (Fig. [548]).—300 species; especially in northern temperate zones; the majority on mountains (Soldanella, Androsace, etc.); almost absent in the Tropics. A large number are ORNAMENTAL PLANTS, e.g. Primula auricula (from the Alps), P. sinensis (China), P. elatior (Oxslip, a native) and grandiflora, etc. Cyclamen europæum (Alpine Violet); the tubers are poisonous.
Order 2. Myrsinaceæ. Trees or shrubs; evergreen, tropical Primulaceæ with fleshy fruits and few seeds, embedded in the placenta. The leaves are nearly always dotted with yellow glands (schizogenous resin-receptacles).—550 species; especially Am.—Ornamental plants: Ardisia crenulata (W. Ind.); other genera: Clavija, Maesa, Theophrasta (barren sepal-stamens), Myrsine, Jacquinia (barren sepal-stamens), etc.—Ægiceras, allied to this order, comprises arborescent plants, often growing with Rhizophora in tropical forests, along the shore. The embryo germinates while still in the fruit.
Order 3. Plumbaginaceæ. This order has a position of the stamens similar to that in Primulaceæ (S5, P5, A0 + 5, G5), but it differs from these in the flower, which has generally a membranous, dry, thin, coloured, folded, almost entire calyx and an almost entirely polypetalous corolla, which, as a rule, has twisted æstivation and is only united with the stamens at its base; but more especially it differs in the ovary, which bears 5 free or almost free styles and only 1 basal ovule with a long, twisted funicle (the placenta of the Primulaceæ is here so much reduced that it bears only 1 ovule). The fruit is a nut or capsule. The radicle is turned outwards. Endosperm mealy.—To this order belong herbs or under-shrubs, which are especially natives of the sea-coast and of salt-steppes; they also resemble the Primulaceæ in the scattered, undivided, entire leaves (without stipules), often in rosettes, and the inflorescence borne on a long stalk. In opposition to the Primulaceæ, the bracteoles are typically present, and hence the branching is generally cymose (scorpioid).
Armeria (Thrift) has a round capitulum, composed of closely-packed dichasia, surrounded at its base by an involucre with peculiar prolongations, directed downwards, and united into a sheath protecting the intercalary zone of growth. The pericarp is finally ruptured at the base, and drops off like a hood.—In Statice (Sea-lavender), the unipared scorpioid cymes are prolonged and collected into panicle-like inflorescences.—Plumbago is the genus which approaches nearest to the Primulaceæ, and differs most from the characters given above. It has capitate or spike-like inflorescences, a salver-shaped corolla, and the stamens are not attached to the corolla. The style is only divided at the extremity; the calyx is not membranous, but is covered with sticky, glandular hairs.
250 species; chiefly in the Mediterranean and about the Caspian Sea, on salt-steppes and beaches. Some are Tropical; a few are ornamental plants.