Ophioglossum reticulatum aka Netted Adder's Tongue

Ophioglossum reticulatum is also known as adder’s tongue fern. It belongs to the fern family Ophioglossaceae. This small plant lives for more than one year. It grows across tropical and subtropical parts of the world. Its range spans Africa, Asia and the Americas. It favours wet tropical climates but grows in many habitats. These include damp grassland, forest edges and rocky ground. It also grows beside roads and on termite hills.

Plants reach about 0.5–0.7 feet (0.15–0.2 metres) tall. One account gives a top height of 1.1 feet (0.35 metres). The stated garden spread is about 0.3 feet (0.1 metres). Yet stolons, or spreading stems, can form broad groups beyond this. The oval fronds have a heart-shaped base. Sterile fronds reach 0.16–0.26 feet (0.05–0.08 metres) long. Fertile fronds can reach 0.66 feet (0.2 metres). A short, upright rhizome supports the plant. This stem has the shape of a cylinder. Where seasons change, fronds appear only in the rainy season. This fern makes spores, not flowers.

It grows in full sun or part shade. Wild plants grow on bare rock shelves and in woods. It suits sandy or loamy soil with an acid-to-neutral pH. Keep the soil moist to wet while it grows. Sources list USDA zones 10–12 for growing it outdoors. Plants grow slowly, and spores are hard to raise. Take care when you divide plants: the rhizome breaks with ease. Plants grown from spores may yield leaves after one to two years. Those grown from rhizomes may yield leaves after about six months.

People gather young fronds to eat as a wild vegetable. Some local markets sell them. Few growers raise the plant as a food crop. The leaves taste sweet. People eat them in salads or cook them as greens. A brief blanch keeps their texture; long boiling makes them slimy. Some growers keep plants in pots for use in folk medicine. Reported uses include rhizome washes for boils and leaf mixtures for wounds. These records show past use, not proof that such treatments help. People also use it as ground cover. It may help stop soil from washing or blowing away.

Insects and molluscs feed on the fronds and can cause damage. The plant can grow as a weed in crop fields. Its small size limits the harm it causes there. Sources report no known cases of poisoning from this species. That does not prove that every use is safe. Their safety notes also cover hazards found in other ferns. Those broad warnings do not prove this species contains toxins.