FERNS 151 Adder's Tongue (Ophio- glossum vulgatum). in which ferns are fecundated is a modern discovery, but the process may be watched un- der the microscope by so wing the spores of any common fern in a moist place. The spore swells with the moisture and ruptures its walls; a little radicle or rootlet is thrown out, consist- ing of a single cell, and at the same time an- other cell spreads out as a tube of irregular fofm, which soon forms partitions through its mass, and by multiplica- tion of these cells be- comes a small green leaf- like expansion called a protJiallus. On the un- der surface of this spring organs of two kinds, the antheridia and arcTiegonia. The former are filled with minute spiral bodies called an- therozoids, which have cilia and the power of motion in water, which is always abundant on the under side of the )rothallus; when mature they pass into the ihegonia, which are cup-like organs, open rhen mature, and containing one or more cells rhich the contact of the antherozoids causes develop, and soon a root appears, then the irst frond, and so on until the complete fern is ie result. The species of ferns at present de- iribed are 2,235, although some botanists make the number above 3,000. In the earlier geolo- gical ages ferns formed a most important part " the vegetation, as is plainly seen in the coal ields, where numerous fronds and stems are reserved; but from the general absence of
- uctification on these remains, it is often im-
sible to distinguish the species. They are low found all over the world, but especially in ie warmer and moister climates ; thus in the Lntilles they comprise ^ of the vegetation, in )ceanica or |, in St. Helena , in Juan Fer- idez , and in England -fa. The Hawaiian islands and New Caledonia are particularly rich species. The tree ferns are chiefly confined the torrid zone, but Martens found them 50 high in Japan, and Robert Brown found irborescent ferns at the extremity of Tasmania, id even at Dusky bay in New Zealand, near lat. 46 S. Most tree ferns are easily propa- ited by planting sections of their stems, which ily leaf out. For the classification of ferns, rhich is very unsettled and depends on tecbni- il differences, see Hooker's " Genera," Hooker id Baker's "Synopsis," or Smith's "Ferns, British and Foreign ;" and for local descrip- tions see local floras. The uses of ferns are lot very prominent. On the Hawaiian islands ie stem of a tree fern is often baked in the im cracks of the volcanoes, and by long cooking becomes quite palatable, although ra- ther leathery, and tasteless without salt. The enlarged bases of the petioles of other spe- cies are cooked and eaten in times of scarcity ; when raw they smell precisely like a raw po- tato. The stems and midribs of some smaller species are woven into baskets and hats. A few species are considered medicinal, and some are aromatic and used to scent cocoanut oil. In cultivation ferns may be adapted to a va- riety of localities ; for, although generally found in shady places, many thrive in the full tropical sun if the air be moist, and some grow on dry rocks and even on the uninviting surface of lava Tree Ferns. 1. Alsophila excelsa. 2. Dicksonia arborescens. 3. Cyathea elepans. 4. Cyathea arborea. 5. Heinitelia speciosa. 6. Drynaria coronans. 7. Platycerium grande. 8. Bird's nest fern. 9. Asplenium lucidum. streams. A compost of peat or bog earth, de- cayed leaf mould, yellow loam, and silver sand nT equal proportions, may be used in potting ferns; but it must be well underdrained, and the addition of a few fragments of mortar ^or limestone is advantageous. Several species climb on rocks, like ivies; others cling to trees, or, like the beautiful climbing fern (lygo- dium), run over bushes. About 1830 Mr. N. B. Ward of England, in investigating the trans- formations of an insect, buried its chrysalis in some earth in a closed glass bottle. A seedling fern and a grass sprang up from the soil and grew within the confined atmosphere of the
