Fig. 526.—Long. sect. of flower.
Fig. 527.—Flower opening.
5. Chamælaucieæ. Australian shrubs with heath-like appearance; they differ from the other Myrtaceæ in having a unilocular ovary with few, basal ovules, and a 1-seeded nut. The sepals are often pappus-like, and divided into many bristles.—Chamælaucium, Darwinia, etc.
This large order (2,100 species) is confined almost entirely to the Tropics, being found principally in America and Australia. In Europe, only Myrtus communis.—Several are useful on account of the large quantity of volatile oils (contained in internal glands): the flower-buds (“Cloves”) of Eugenia caryophyllata (the Moluccas, cultivated in the Tropics, Figs. [523], [524]); the unripe, dry berries (“Pimento”) of Myrtus pimenta (Pimenta officinalis, W. Indies); Cajeput oil is extracted from Melaleuca minor and leucadendron (East Asian Islands). Eucalyptus globulus (Australia) has of late years become well known on account of its rapid growth, its hard wood, and its antipyretic qualities; it is cultivated on swampy soils, which it helps to drain.—Officinal: “Cloves,” and the cork of both stem and root of Punica granatum. Several have EDIBLE FRUITS, such as Psidium guyava (Guava, var. pomiferum and pyriferum, Am.), Eugenia cauliflora and others, E. jambosa, Punica granatum (the Pomegranate), etc. Edible seeds (with abundance of fatty oil): “Brazil nuts” from Bertholletia excelsa (Trop. S. Am.). “Bay-rum” is extracted from the leaves and fruits of the Bayberry-tree (Pimenta acris, W. Ind.); Guava-rum from the berries of Eugenia floribunda. Tannin is found in large quantities e.g. in Punica. Gum is formed by many Australian Eucalypti (“Gum-trees”). Ornamental plants cultivated in this country are: Myrtus communis (Mediterranean), several in conservatories, especially the Australian Leptospermeæ, Eucalyptæ and others.
Family 24. Umbellifloræ.
The flower is regular, ☿, and completely epigynous, 5- or 4-merous, with 1 whorl of stamens and 5–2 carpels. Sepals very small, tooth-like. The corolla is polypetalous, most frequently valvate in æstivation (least pronounced in the Umbelliferous plants). Round the base of the styles, which are generally free, there is an epigynous (undivided, or divided) nectar-disc (“stylar-foot”: Figs. [528] B, C, D; [539]); the number of loculi in the ovary equals that of the carpels; only 1 pendulous (anatropous) ovule (Fig. [528] C) in each loculus. Endosperm copious (Fig. [528] D). To this must be added that the inflorescence in the majority of cases is an umbel or a capitulum, especially in the Umbelliferæ and Araliaceæ. Stipules are absent, but most frequently the base of the petiole forms a large sheath.
The Umbellifloræ are on one side so closely allied to the Frangulinæ, especially Rhamnaceæ, that they may perhaps be regarded as the epigynous continuation of this family. On the other hand, the similarities to the Rubiales, especially those between Cornaceæ and Sambuceæ, are so great that there is scarcely any character to distinguish them except the polypetalous corolla of the former and the gamopetalous corolla of the latter. Whether this is more than a merely analogous resemblance, and if not, whether the Cornaceæ at least should not be included in the Rubiales, must be left in abeyance.—The sepals are very small, as is generally the case in epigynous flowers.
Order 1. Cornaceæ. The majority of the species are shrubs with solid internodes, opposite (rarely scattered) leaves, which are simple, entire (rarely incised), penninerved, without stipules or large sheaths; flowers 4-merous (most frequently S4, P4, A4, G2), borne in dichasia which are either collected into corymbs (e.g. Cornus sanguinea), or in closely crowded umbels or capitula (Cornus mas, C. suecica), in which latter case there is often a large, leafy, or coloured, most frequently 4-leaved involucre round the base of the inflorescence; the style is undivided, with lobed stigma; the raphe of the ovule is turned outwards. The fruit is a berry or a drupe, with a 1–4-locular stone or 2 free stones.