Their fresh greenery embracing a wide range of tones, their striking and frequently unusual habit, and the decorative effects of their graceful fronds and lush foliage are what makes ferns and selaginellas such favourite house plants.
Most ferns grow in shady and damp locations. Many are indigenous to tropical rain forests. Their number includes epiphytes which grow on the trunks and branches of trees. On the other hand, there are also ferns that grow in locations that are definitely dry, even though shaded or at least partially shaded, such as rock crevices. Another extreme environment is by water and marshes.
Ferns do not produceand, therefore, neither fruits nor . They reproduce by means of spores, produced in abundance as a very fine powder- in sporangia growing on the undersides of the . Whereas a develops directly into a young plant resembling the parent, a fern spore that falls to the ground first develops into a prothallium, a flat body measuring only a few millimetres. This bears the organs that produce the male and female sex cells and is where fertilization takes place. Only a fertilized egg cell can develop into the graceful fronds of a fern.
Selaginellas are usually inhabitants of tropical rain forests; only a few grow in the temperate zone. Theirare forked and thickly covered with small, scale-like leaves that vary according to the in which they grow. Those that grow in the axils of the forks are symmetrical. The other leaves on the stems are faintly asymmetrical. A leafless organ, called a rhizophore, grows downward at the point where the branches. At the tips of the stems there are small cones composed of sporophylls, bearing on their upper sides a kidney-shaped sporangium filled with spores.
The genus Nephrolepis includes about 30 species, some of which are epiphytic, others terrestrial. N. exaltata has graceful arching fronds up to 80 cm (31 ½ in) long and divided into numerous fine segments. The young fronds, like those of all ferns, are tightly furled inwards, unfurling as they grow. Besides the type species, many cultivars are grown. These differ in the division of theblade, in the individual leaflets (which may be wavy, flat or straight), in their habit of growth, or in the size of the clumps. The cultivar ‘Hillii’, with bipinnately compound, narrow, crowded leaflets is very lovely. ‘Rooseveltii’ has wavy leaflets; ‘Whitmanii’ has very fine, multipinnately compound leaflets; ‘Teddy Junior’ has wavy, furled leaflets coloured dark green.
This fern tolerates ample light and normal room temperature. It does not require a very humid atmosphere. In fact it is more seriously affected by too much water rather than by occasional drying out. Feed during the growing period. The recommended growing medium is a mixture of two parts peat, two parts leaf mould and one part sand. N. exaltata can also be grown by. Propagate by dividing clumps when or by means of the plant’s runners. When these come in contact with the they put out . After they have been detached from the parent plant, they will develop into new individuals.
The genus Platycerium includes 18 species from tropical forests throughout the world, mostly in Asia, less often in the Americas. P. bifurcatum is native to the forests of Australia and Polynesia, where it grows as an epiphyte on trees. It is a very interesting fern with two types of leaves. One kind is kidney-shaped to orbicular, green at first, later brown, adpressed to the trunks of trees. These serve to hold the plant to the support and also to capture humus and water. The second kind is forked, green, with rusty-brown sporangia on the underside. The silvery tint of the leaves is produced by numerous stellate trichomes which are visible only with the aid of a microscope.
The recommended growing medium is a mixture of, coarse peat and crushed beech leaves. Platyceriums do well in , wooden baskets and on sheets of bark, as well as on epi phyte stumps, in plant-cases and greenhouses. In summer, shade it from direct sun. It thrives in houses with central heating because it requires rather warm conditions, even in winter. Misting the leaves is very beneficial.