Pteris

Pteris (Pteris) Is a cosmopolitan genus of ferns in the Pteris family (Pteridaceae)that grows on all continents, with the exception of Antarctica. Usually they are inhabitants of mature forests, less often they can be found in secondary forests, in clearings, along rocky streams, and sometimes on rocks and trees. Most of the pteris grows in tropical or subtropical climates, but some species have mastered temperate regions.

The name of the genus comes from Greek pteris, which means "wing", it is given due to the shape of the leaf blade.

This is one of the most diverse genera of ferns, there are about 200 species in it, often very different in morphology and habitat conditions. It is probably polyphyletic (the species collected in it come from different ancestors). Modern research at the genetic level will help to streamline the taxonomy of ferns.

A common feature for all species united in the genus Pteris is the bordering arrangement of sporangia in one line along the marginal vein, covered from above by the folded edge of the leaf blade.

These are herbaceous perennial plants. From an erect or creeping short rhizome covered with scales, flat fronds (leaves) collected in a rosette extend upwards. Petioles are erect, thin, approximately equal to the leaf blade. Young leaves are rolled into a spiral, which gradually unwinds as it grows. The leaf blade is from pinnate to four-pinnately cut, with pairs of leaflets (segments) located on both sides of the rachis (central part), with the basal leaflets being the shortest and often forked branched. Subsequent pairs are longer, and then become shorter again, and the leaf blade ends in a thin and long unpaired segment. The leaflets of spore-bearing leaves are narrower, with a curled edge, while the leaflets of vegetative leaves are usually linear-lanceolate, with a sharp top.

The primary root is quickly replaced by many small, branched adventitious roots that grow along the entire length of the rhizome.

In the pteris culture since the middle of the 18th century, about 30 ornamental species are grown in the open ground of the subtropical and tropical zones, where they are sometimes naturalized. And in cooler climates, these are popular indoor and greenhouse plants. There are many variegated forms among them. Many species of pteris have the ability to take high concentrations of arsenic and antimony from the soil and accumulate in themselves. It can be used in the purification of drinking water from these harmful impurities.

Cretan pteris (Pteris cretica) grows in Greece, the Mediterranean, the Middle East and the Caucasus. Perennial terrestrial  plant 30-60 cm in height. Creeping rhizome, covered with brown bristles. Sterile (vegetative) leaves 30-40 cm long, fertile (fertile) leaves up to 60 cm or more. Petioles 15-30 cm long, erect, rigid, flexible, glabrous, yellow or light brown. Leaf blades are pinnate, 15-30 cm long and 10-20 cm wide, ovoid or oval in outline, leathery. Segments of vegetative leaves are located oppositely on the rachis, up to 7 pairs, 7-15 (20) cm in length and up to 2 cm in width, linear-lanceolate, dentate along the edge, extended to the apex, acute, almost sessile, while the lower pair is often forked into two or three linear segments. Fertile leaves have narrower, whole-edged segments. This species lacks wings along the rachis.

In culture since 1820. It is widely cultivated worldwide as a container and pot plant, and in the subtropical regions of the southern zone it is grown outdoors. Has many decorative forms:

• Parkeri - a variety with wide green leaves, forming dense thickets. Reaches 80 cm.
• Childsii - with wide leaves, incised along the edges and small crested tips.
• Distinction - the variety is smaller than the main species, with deeply lobed leaves branched at the tips.
• Rivertoniana - a very decorative and easily growing fern with lacy leaves.Unusual cultivar with long, pointed, irregularly cut leaves, arranged in 4-5 pairs, often with small ridges at the tips.
• Wimsettii - a more perfect form of the Rivertoniana cultivar. Compact, with deeply and irregularly cut leaves, the tips of which are often comb-like. It can reach 60 cm.
• Rowerii - very attractive and hardy compact fern with elaborate leaf blades of deep green color. Grows up to 40 cm.
• Wilsonii - with lobed leaves, often with fan-shaped crests on the tips of the leaflets.
• Gautheri - it is characterized by wide leaves.
• Ouvardii - with narrow linear leaves.
• Albolineata - a variety with a narrow creamy white stripe in the middle of each leaf. Grows up to 40 cm.
• Mayii - in addition to the light stripe in the center, it has highly branched leaf tips. Compact, up to 40 cm, and very decorative variety.
• Alexandreae - a variety with white variegation, the tips of the leaves are cut and twisted.

Quivering pteris(Pteris tremula) native to eastern Australia and New Zealand, where it grows in rainforests or protected areas. It is a large terrestrial fern with an erect rhizome covered with narrow brown scales. Fries up to 2 m long, triple pinnate or more complex, pale green, lacy. It has a fast growth rate and in warm climates it easily naturalizes, often becoming a weed plant.

Long-leaved pteris(Pteris longifolia) - grows in the tropical forests of Central and South America. Creeping rhizomes are covered with brown scales. Leaves with short petioles, can reach a length of 80 cm, with a width of about 10-20 cm.The leaf blades are pinnate, consist of 10-30 pairs of narrow segments (each of which is 5-10 cm long and about 1 cm wide), diverging from the rachis almost at right angles.

Pteris tape(Pteris vittata) native to Asia, southern Europe, tropical Africa and Australia. It can often be found in cities, where it settles in cracked buildings and concrete structures. Naturalized in California, Texas, and the Southeastern United States. Possesses a high degree of absorption of arsenic from the soil.

The rhizome is short, creeping or raised, about 8 mm in diameter, covered with brown bristles. Leaves closely spaced, curved, herbaceous to slightly leathery. Petioles 20 (5-50) cm long, brown, glabrous, with age at the base covered with scales. The leaf blade is oblong-lanceolate in outline, up to 1 m long and 40 cm wide, pinnate, with 20-40 linear segments tapering at the apices, located opposite each other on the rachis, and one terminal at the end. The middle segments are the longest, up to 15 cm, and no more than 1 cm wide. Outwardly, it is very similar to long-leaved pteris, but the segments of its leaf depart from the rachis at a sharper angle.

Pteris xiphoid (Pteris ensiflormis) originally from the Asia-Pacific region. A fern with narrow triangular, double-pinnate, dark green leaves, often with grayish-white stripes. Fertile fronds 30-45 cm long, with 4-5 pairs of lateral parts extending from the rachis, each with several dentate basal segments. Sterile leaves are shorter, with narrower, non-overlapping lobes. In culture, there are mainly two varieties:

• Evergemiensis - reaches 30-40 cm in height and about 60-80 cm in width. A very attractive domed fern with spectacular variegated double-pinnate leaves, which consist of narrow segments with silvery-white stripes in the middle and dark green, slightly wavy at the edges. Commonly known as Silver Lace.
• Victoriae - slightly different from Evergemiensis in that its sterile leaves are smaller and less decorative, and the variegated stripe is located only along the central axis.

Pteris multi-cut(Pteris multifida) native to Korea, China, Japan, Vietnam, widely naturalized elsewhere. Fern with short creeping rhizomes, densely covered with dark reddish-brown scales. Leaves up to 60 cm in height and about 25 cm in width.Petioles are sometimes scaly at the base and glabrous above, dark brown to straw. On the rachis there are from 3 to 7 pairs of very narrow and long segments, the lower ones are dissected, the upper ones are simple, connected by a winged rachis, sometimes with a serrated edge. It looks like a spider, hence its name Spider fern.

Pteris shadow(Pteris umbrosa) grows in the jungle of Eastern Australia. In shady places, it can form large colonies. Small populations are found near Sydney, possibly due to naturalization. The rhizome is short-creeping, covered with small dark brown scales. Leaves grow vertically upward, reaching 1–2 m, from pinnately dissected to incompletely double pinnately dissected, dark green. Petioles beige to red-brown, more than 30 cm long. Rachis is brown. Segments are narrow-lanceolate, smooth, 10-30 cm long, sometimes finely serrated along the edges of sterile leaves.

About cultivation - in the article Pteris in indoor conditions.