Fig. 499.—Flower in longitudinal section.
Fig. 500.—Fruit and receptacle in longitudinal section.
5. Agrimonieæ. The receptacle is more or less cup- or bell-shaped, and almost closed at the mouth; it is persistent and envelopes the nut-like fruitlets, but is dry, and in some species hard, the fruitlets being firmly attached to it. In biological connection with this the number of the carpels is generally only 1 or 2, and the whole becomes a false nut (Fig. [500]). Herbs.—Agrimonia (Agrimony; Figs. [499], [500]); the perianth is 5-merous, stamens 5–20. The receptacle bears externally, on the upper surface, a number of hooked bristles which serve as a means of distribution for the 1–2 achenes which are enclosed in it, and hence the entire flower finally falls off. The inflorescence is a long upright raceme. These bristles are arranged in whorls of 5 and 10, of which the uppermost alternate with the sepals.—Alchemilla (Ladies-mantle; Fig. [501]) has 8 green perianth-leaves in two whorls (some authorities consider the four outer as an epicalyx, and the flower therefore apetalous), and 4 stamens alternating with the innermost whorl. There is only one carpel with a basal style and capitate stigma. The flowers are small and greenish, the filaments jointed. The anthers open by one extrorse cleft. The leaf-sheath entirely envelops the stem; the leaves are palminerved. A. aphanes has often only 1–2 stamens. The following genera, with 4-merous flowers borne in short spikes or capitula, are allied to this group. Sanguisorba has entomophilous, ☿-flowers with 4(-20) stamens, 1 carpel; stigma papillose.—Poterium; spike or capitulum, the uppermost flowers are ♀, the lowermost ♂, and some intermediate ones ☿ (the order of opening is not always centripetal); S4, P0, A20–30, G2, the long styles having brush-like stigmas (wind-pollination). Leaves imparipinnate.
Fig. 501.—Flower of Alchemilla in longitudinal section.
Pollination. A yellow ring on the inner side of the receptacle, inside the stamens, serves as a nectary when any honey is formed; this, for instance, is not the case in Rosa, Agrimonia, Spiræa ulmaria, S. filipendula, S. aruncus, etc., to which the insects (especially flies and bees) are allured by the quantity of pollen. Homogamy and slight protogyny are frequent, in many instances self-pollination also is finally possible. Poterium, with the long-haired stigma, is wind-pollinated.—About 550 (1100?) species, especially in northern temperate regions.—Uses. Officinal: the petals of Rosa centifolia and gallica, the fruits of the Raspberry (Rubus idæus), the rhizome of Geum urbanum, the flowers of the Koso-tree (Hagenia abyssinica or Brayera anthelmintica).—The bark of Quillaja saponaria (Chili) is used as soap and contains saponin. “Attar of Roses” from Rosa damascena, centifolia and other species, especially from the southern slopes of the Balkans. Many species and varieties of Roses are ORNAMENTAL plants: from S. Europe, Rosa lutea (the Yellow Rose), R. gallica (the French Rose) and R. rubrifolia; from W. Asia, R. centifolia, of which the Moss Roses (R. muscosa and cristata) are varieties, and R. damascena; from India and N. Africa, R. moschata (the Musk Rose); from China, R. indica (Tea Rose) etc., besides the native species and the varieties which have been derived from them. In addition, Kerria japonica, species of Potentilla, Rubus odoratus from N. Am., and many species of Spiræa from South-eastern Europe and N. Am. Esculent: the “hips” of R. mollissima, R. pomifera, etc.; the fruits of Rubus-species: Raspberry (R. idæus), Cloudberry (R. chamæmorus), Blackberry (R. fruticosus), etc.; of Fragaria-species (F. vesca, collina, grandiflora, etc).
Order 2. Amygdalaceæ. Trees or shrubs with rosaceous flowers; leaves simple with caducous stipules; a regular, perigynous flower, the receptacle being partly thrown off by a circular slit; sepals 5, petals 5, stamens 20–30; gynœceum simple, formed of 1 carpel (hence oblique, Fig. [502]), with terminal style and 2 pendulous ovules, ripening into a drupe (Fig. [503]).—The leaves are penninerved and frequently have glands on the stalks and edges; thorns (modified branches) often occur, i.e. dwarf-branches, which, after producing a few leaves, terminate their growth in a thorn (e.g. Prunus spinosa). The vernation of the foliage-leaves varies in the different genera; in the Almond, Peach, Cherry, and Bird-Cherry they are folded; in the Apricot, Plum, Sloe and Bullace, rolled together. In some the flowers unfold before the leaves (Amygdalus, Armeniaca). That the gynœceum is formed of 1 carpel is evident in this as in other instances (e.g. in the Leguminosæ, which are closely related to this order), from the fact that the carpel is oblique, and has only one plane of symmetry, and similarly in the fruit there is a longitudinal groove on one side which indicates the ventral suture. It is only exceptionally that both ovules are developed. In abnormal instances more than 1 carpel is developed.
