Fig. 343.-Morus alba ♀ inflorescence.
Fig. 344.—Morus nigra fruits.
A. Moreæ. The filaments are incurved in the bud. Leaves folded in the bud—Morus (Mulberry) (Figs. [342–344]). Monœcious. The inflorescences are catkin-like in appearance, but in reality composed of many small dichasia. The flowers are similar to those of the Nettle, but with 2 carpels: in the ♂ with perianth 2 + 2, and stamens 2 + 2 (Fig. [342]), in the ♀, perianth 2 + 2, and 2 carpels in regular alternation. The small drupes are enveloped by the perianth, which eventually becomes fleshy, and as all the flowers on the axis very accurately fit together, the collection of fruits is formed, which we call a Mulberry (Fig. [344]). The leaves are folded in the buds, and have small stipules. The following are allied to Morus:—Maclura, Broussonetia (the Paper-mulberry tree) which has spheroid ♀ inflorescences (made up of dichasia), etc.
Dorstenia presents an interesting transitional form to the Fig in its flat, open, and, in some instances, lobed inflorescence on which the ♂ and ♀ flowers are sunk in grooves. Indications of a somewhat similar structure are found in certain Nettles, the sympodial axes of the dichasia becoming flatly expanded. The fruits are 1-seeded, but, nevertheless, spring open and eject their seeds.
B. Artocarpeæ. Filaments straight in the bud; foliage-leaves with convolute vernation. An interpetiolar leaf-sheath (ocrea) formed in the axil of each leaf by the connate stipules, covers the younger leaves as a hood. It falls off as the leaf expands, and leaves a ring-like scar on the stem.—Ficus (the Fig). The inflorescence (the so-called syconus) has a pear-shaped, fleshy, but hollow axis, on the interior surface of which the flowers are situated (Fig. [345]). It is a kind of capitulum, with a hollow receptacle, whose “involucral” leaves close over the entrance to the interior; it is not, however, a simple capitulum, but a coalescence of cymose inflorescences. The edible parts are the fleshy stem-portion and perianth-leaves. The ♂-flower has a 2–6 divided perianth, 1–2 (–6) stamens; the ♀-flower has an oblique ovary. The fruits are drupes, with thin flesh.—Many species have aerial roots, and some live as epiphytes on trees. Pollination, in the edible Fig, is effected by a small Gall-wasp (Cynips psenes L.), which lays its eggs in the Fig, and hence carries the pollen away. Even in very ancient times it was customary to hang infected wild Figs on the branches of cultivated ones, so that the young Gall-wasps, as they emerged, could immediately effect the pollination (caprification). Ficus carica, and other species, have two kinds of ♀-flowers, besides the ♂-flowers. One kind has a short style and no stigmatic hairs, and it is only in the ovaries of these that the wasps lay their eggs (gall-flowers); the other kind has a long style and well-developed stigmatic-hairs, but the wasps cannot reach their ovaries—these are “seed-flowers.” There are, moreover, two kinds of plants of Ficus carica; ♀-plants, which have only seed-flowers, and bear the edible Figs, and ♂-plants (called “Caprificus”), which bear inedible fruits, and have ♂-flowers at the upper part of the Fig, but gall-flowers at the base. [The Caprificus, at Naples, bears three crops of inedible Figs each year, viz. Mamme (April), Profichi (June), Mamnoni (August). The ♂-flowers are produced especially in June, the first Figs being almost entirely ♀, and the last having but few ♂-flowers. Each crop produces a new generation of Fig-wasps. The female wasp enters the Figs on the Caprificus, and lays one egg in each flower, with the result that the flower developes into a kind of gall. The mother-wasp dies within the Fig. The male wasp is wingless; it bites a small passage into the ovaries containing the female wasps, and impregnates them; the female wasps then escape from the Fig, those in the Profichi carrying pollen away with them as they pass out. They then enter another Fig, lay their eggs, and die. The edible Fig-tree similarly has three crops in the year, Fiori di fico, Pedagnuoli, Cimaruoli. The wasps, entering these Figs, are unable to lay their eggs in the ovary, but, nevertheless, they effect cross-pollination on entering the Pedagnuoli, which bear fertile seeds.]
Fig. 345.—A Fig in longitudinal section.
The flowers of Brosimum are the most reduced. The perianth is wanting, and the ♂-flower has only 1 stamen. Cecropia (Trumpet-tree), in S. Am., has its pith divided into chambers; these are inhabited by ants, which feed upon small food-bodies formed on the swollen base of the petioles. The leaves are petiolated, often shield-like, fringed or lobed, and sometimes with white felted hairs. They serve as food for Bradypus (the Sloth). Sorocea; Castilloa.
About 300 species exclusively in the warmer climates. The white Mulberry (M. alba, from China, India, Mongolia) is cultivated for the sake of its leaves, which are the indispensable food for silkworms. The black Mulberry (M. nigra, W. Asia) is cultivated for its fruits, which are used for the officinal Mulberry juice. The ordinary Fig-tree (Ficus carica) is from the Mediterranean. The fruit of the well-known Oriental Sycamore (F. sycomorus) is edible. The Bread-fruit tree (Artocarpus incisa) and the Jack (A. integrifolia) have their home in the South Sea Islands, and are cultivated in tropical countries. The Bread-fruit is morphologically the same as the Mulberry. It has a very large, spheroid inflorescence, whose floral-leaves and perianth become fleshy and united into one nutritious mass, together with the axis, which is also fleshy. The milky juice of the India-rubber tree (Ficus elastica, East Indies, a common house-plant), and of Castilloa elastica (Am.) is the raw material of India-rubber. The milky juice of Galactodendron utile (Cow-tree, S. Am.) is saccharine and nutritious, but in Antiaris toxicaria (the Upas-tree, of Java) it is a strong poison. The bast of the Paper-Mulberry tree (Br. papyrifera, Eastern Asia); is used in Japan for paper. Shellac is obtained from a small, hemipterous insect (Coccus lacca), which lives upon Ficus laccifera and F. religiosa (the Bo-tree, sacred to Buddha), E. India. The wood of Maclura aurantica (Am.) has a yellow colour, and is known as yellow Brazilian wood.