Ferns ( Pteridopsida )
Order Polypodiales ( Polypodiales )
Family Polypodiaceae ( Polypodiaceae )
Representatives of this family are ferns with creeping or erect, thin or thick, bare or scaly rhizomes. Leaves are usually alternate, sometimes clustered, thin, herbaceous, sometimes evergreen or winter-hardy. Leaf blades of young plants are spirally coiled, while those of adult plants range from simple to pinnately compound, glabrous or pubescent. Sporogenous leaves do not differ from vegetative ones or have a different shape and size. Several species of plants from this family, predominantly bog plants, are cultivated in aquariums and humid greenhouses.
Genus Microsorium — Microsorium, Microsorum.
Microsorium can rightly be called a viviparous plant. A single piece of a frond is enough for a whole forest of small bushes to soon grow.
Java fern — Microsorium pteropus. “Java fern”.
“1” Synonym: Leptochilus decurrens. Origin — tropics of Southeast Asia. (Eng. — Java Fern, African Fern). Among underwater ferns, it is the most undemanding and shade-tolerant. Height does not exceed 25-30 cm. Bush width is 12-20 cm. On a long creeping rhizome, lanceolate leaves ranging from bright green to dark green are arranged alternately. The leaves reach a height of 25-30 cm and form dense thickets. Leaves are stiff, simple, lanceolate, bright green, on short petioles. It has an uneven, seemingly crumpled surface, which gives the microsorium thickets a special originality. It grows throughout the year, but very slowly even under the most favorable conditions.
— Microsorium pteropus “Filippine” — Leaves are thinner, of variable length from 20 to 30 cm, and very narrow, from 1 to 2 cm. This variety can tolerate the presence of salt, making it especially suitable for brackish aquariums. It can also be planted not too deep in the substrate; — Microsorium pteropus “Narrow Leaf Nana” — Narrow-leaf dwarf; — Microsorium pteropus “Narrow Leaf” — Narrow-leaf Java fern, has narrower leaves that grow at a less acute angle from the stem, up to 15-20 cm long. Much easier to root in any environment; — Microsorium pteropus “Needle Leaf” — Leaves are narrow with a more horizontal growth. Rhizomes are also thinner compared to the normal type; — Microsorium pteropus “Red” — Has a wider leaf than the original species, but its main feature is reddish-brown new leaves, though with age this color turns into the classic green;
— Microsorium pteropus “Trident ” — Leaves are slightly darker, very thin (even less than 1 cm), but with extensions of several centimeters, creating a continuous row of long tridents; — Microsorium pteropus “Tropica” — Has faster growth and looks more voluminous, leaves up to 45 cm, however, the main differences lie in leaf morphology: juvenile form is toothed, with age the teeth gradually elongate with variable length and width; — Microsorium pteropus “Undulata” — Slightly larger than the original form with wide leaves up to 4 cm wide; — Microsorium pteropus “Windeløv” — This cultivar is smaller, leaves up to 20 cm long, forming a denser and thicker bush. Characterized by branching tips on the small leaves;
“2” Grows satisfactorily in water at temperatures above 24°C. As the temperature drops, growth slows down. Water characteristics, primarily hardness, are very important for the successful cultivation of this plant. Total hardness should not exceed 6°dH, and the active water reaction should range from slightly acidic to neutral (pH 5.5-7.0). Such conditions are usually created in old water. Therefore, frequent water changes are not required for the Java fern and may even somewhat inhibit its growth. In hard water, black spots appear on the leaves, or the edges turn black. In addition, microsorium does not tolerate high concentrations (1.5 g per liter) of salts in the water. Therefore, the water should not be salted. In most regions of our country, natural water is poorly suited for growing Java fern due to its relatively high hardness. Intensive aeration and a strong water current impair plant growth.
Lighting is moderate (0.4 W/L); it withstands prolonged shading, but its growth practically stops under such conditions. Nevertheless, to obtain large, beautiful bushes with corrugated leaves, bright light is required. Daylight duration is 12 hours. Under good conditions, the fern leaves remain pure green for years, while under poor conditions, they become covered with black spots of dead tissue. The leaf blade is so dense that even after turning completely black, it remains in its place for a long time.
“4” Forms a heavily branched, creeping, stiff, dark-green rhizome. Single alternate leaves depart vertically upward from it, and adventitious roots are dark brown, covered with fine hairs. The root system of this fern has the property of attaching to individual stones that make up the aquarium substrate. To improve the plant’s growth performance, it is recommended to apply mineral fertilizers periodically, about 1-2 times a month. A piece of boiled acidic peat is recommended to be placed under the roots. Mineral fertilizers added to the water have a positive effect on growth. The nature of the substrate does not matter, as the rhizome spreads along the surface of the hard base of the soil without penetrating deep. The fern roots equally well both on coarse substrate and on stones. This is exactly how the plant should be planted: without burying the rhizome in the soil.
“5” This fern can be grown in an aquarium of any size, placing it near the side walls and in the midground. In a small body of water, the bush will play the role of a large solitary plant, while in a spacious one, it can be used for group planting. It can form the basis of very beautiful compositions. Microsorium is also used as spawning substrate for many egg-scattering fish. The plant grows well on wood, stone, and in a floating state, which does not last long because under its own weight it sinks to the bottom. It has no roots and does not need to be planted in the soil, but with the help of root-like formations — rhizoids, it easily attaches to stones, driftwood, etc., so initially it should be held down with a stone. If the plant is planted in the soil, the rhizoids should not be buried, otherwise they will rot.
When growing microsorium, it is essential to consider that it completely intolerant of disturbance and the presence of suspended organic particles in the water. In the aquarium where it grows, plants should be replanted and fish caught as rarely as possible. Intensive aquarium aeration, strong water current, and the presence of substrate-digging fish significantly worsen the growth of this fern. It produces 1 leaf per month. As a rule, it is not eaten by herbivorous fish. Even under optimal conditions, it grows slowly. If left undisturbed, it grows to huge sizes. Old bushes in the aquarium can form dense thickets. The plant is undemanding, making it suitable for beginner aquarists.
“6” The fern easily propagates by cuttings, plantlets that develop at the tips of old leaves, and also by spores formed on the underside or margin of the leaf, sometimes on adventitious roots. Black spots on the underside of the leaves are spores, not signs of disease, as many mistakenly believe. Buds form on old, decaying leaves, from which small ferns develop. After the old leaf dies, the daughter plants detach and float to the surface. A rhizome gradually develops in the floating young plant, under the weight of which it sinks to the bottom. The large rhizome of the plant is divided into parts with 3-4 leaves. A young plant then develops from each such part.
Java fern “Tropica” — Microsorium pteropus “Tropica”.
Young leaves of the “Tropica” fern have an even edge, along which toothed cuts appear as they grow. With age, the leaves become increasingly narrow — the length of old leaves can reach 30-40 centimeters. Young leaves on old bushes generally break down into three parts quickly, which increases bushiness and creates an interesting relief. It is great both for forming the background of an aquarium landscape and as a centerpiece for large aquariums.
This plant differs from other ferns by greater hardiness and resilience. The maintenance conditions for the Java fern “Tropica” do not differ from the standard care requirements for Java ferns, except for the aquarium size requirements. It roots and grows equally well on stones, as this is the normal growth habit of ferns in their natural habitat. When planting, it is advisable to secure the plant with a rubber band or fishing line until it puts out aerial roots. When planting in gravel, the main task is not to bury the horizontally positioned nodes from which rhizomes sprout. They tolerate low lighting normally (though growth slows down) and various water qualities, from soft to hard and even brackish.
It propagates vegetatively; new offshoots appear on old leaves, usually along the margin, but sometimes in the middle of the leaf. Under favorable conditions, the entire old leaf of the fern can become dotted with “plantlets”. Since “Tropica” is a selective cultivar of the Java fern, the characteristic dissected leaf pattern is not passed on to these “bastards”. They have no breeding value and should be removed from the surface of the noble plant.
Microsorum pteropus, Windelov, Philippine, Red, Java fern.
Marsilea quadrifolia, Marsilea crenata, Marsilea hirsute, Pilularia globulifera. 
