Fig. 520.—Lythrum salicaria. One side of the perianth is removed from all three flowers. A is long-styled, B mid-styled, and C short-styled. The direction of the arrows and dotted lines indicates the best (legitimate) methods of crossing.
Peplis (Water-purslane), a small, annual plant, with thin, bell-shaped receptacle without projecting nerves. The small flowers have no petal-stamens, and often also no corolla; fruit indehiscent.—Ammannia is closely allied to it.
365 species; 30 genera; mostly in the Tropics, and more especially S. Am.—Some yield dyes, e.g. Lawsonia inermis (cultivated in Africa and Asia) and Lagerstrœmeria indica; some contain tannin; others are ornamental plants, especially in gardens in warm countries.
Order 2. Blattiaceæ. 12 species. Tropical Asia and Africa. Trees. Formerly included with Punica, but best placed as an independent order.
Order 3. Melastomaceæ. A very natural and very large order (150 genera; 2,500 species), its home being chiefly in tropical S. America, especially the Brazils (termed by Schouw “The kingdom of Palms and Melastomaceæ”). There are both herbaceous and arborescent species, which are easily recognized by the opposite or verticillate, simple leaves which have (with the exception of a few heather-like species) 3–5–7–9 curved veins proceeding from the base of the leaf, and connected very regularly by closely parallel, transverse veins. The flower is perigynous or epigynous; its type is that of the Onagraceæ (4–5-merous; 1 whorl of sepals, petals and carpels, 2 of stamens); the calyx is valvate, the corolla is twisted (to the left) in æstivation; the stamens are very characteristic; in the bud they are geniculate; the anther opens in the often long, beak-like, prolonged point, with 1, less frequently with 2 pores, and has generally ear-like appendages at its base. The fruit is a berry or capsule. These large and beautiful flowering-plants play a very important part in South American landscapes; otherwise they are of slight importance (a few are cultivated in conservatories, e.g. Centradenia, Medinilla, Lasiandra, Tibouchina, Miconia, etc.).
Order 4. Œnotheraceæ (or Onagraceæ). The flowers are arranged in racemes or spikes, ☿, epigynous, regular, polypetalous, 4-merous in all 5 whorls (1 whorl of sepals, petals and carpels, 2 of stamens); 2–3–5–6-merous flowers are less frequent; the calyx is valvate, the corolla twisted in æstivation (the left edge being covered). Gynœceum simple with multilocular ovary; the style is undivided, filiform, and bears a capitate or 4-partite stigma; endosperm wanting; embryo straight.—The majority are herbs, especially water- and marsh-plants; several are shrubs. No essential oils. The leaves are alternate or opposite, always single, and without (or with very small) stipules. The odourless flowers sometimes have a coloured calyx. In some instances (e.g. Œnothera, Fuchsia) the receptacle is prolonged more or less beyond the inferior ovary, and finally falls off. The stamens are obdiplostemonous (carpels epipetalous); the petal-stamens are sometimes suppressed. The anthers in some genera are divided into storeys. The well-pronounced, triangular pollen-grains are connected together by viscous threads. Small stipules are sometimes found, e.g. Fuchsia, Lopezia.
Fig. 521.—Flower of Lopezia.
A. Fruit a capsule. Œnothera (Evening Primrose) is 4-merous, has 8 stamens, a tubular receptacle, and an oblong capsule with loculicidal dehiscence leaving a centrally placed column, bearing the seeds.—Epilobium (Willow-herb) deviates from Œnothera especially in the seeds being hairy (at the chalazal end of the seed).—Chamænerium is a Willow-herb with zygomorphic flowers.—The following may be included here: Clarkia, Eucharidium (an Œnothera with 4 stamens and 3-lobed petals), Godetia and Boisduvalia, Jussiæa (dehiscence septicidal), Isnardia (petal-stamens absent, sometimes the petals also).—Lopezia has a peculiar, zygomorphic flower (Fig. [521]); one of the four sepals is bent forwards and the other 3 backwards; the posterior petals are narrower than the 2 anterior ones which are turned obliquely backwards and bent like a knee, with a greenish nectary at the bend; 2 stamens, one only fertile (the posterior), while the anterior is barren, petaloid, and spoon-shaped; both are sensitive, which is essential for pollination. In Fig. [521], a represents an early stage, in which the stamen and style lie concealed in the staminode; b is the ♂ stage, the stamen projects from the centre of the flower; c, the ♀ stage, the style occupies the place of the stamen.
B. Fruit a berry. Fuchsia generally has a coloured calyx and tubular receptacle; the corolla may be wanting.