Pani niguro shoots

Name and source boundaries

Kew accepts Diplazium esculentum (Retz.) Sw. and includes Nepal in its native range. Its classification field lists Aspleniaceae. The PLOS Table 1 row labels its specimen entry Athyriaceae, while PROSEA’s genus record header says Dryopteridaceae and discusses alternative family concepts. These source-specific classifications are reported without reconciling them. The PLOS row assigns the names Pani niguro and Lauta to collection KSD610; these labels do not identify every fern called niguro or edible fern.

A Nepal food-use record

A 2021 ethnobotanical study reports wild foods from Khilang, Parche and Sikles in Madi Rural Municipality, Kaski. Its Table 1 identifies D. esculentum as collection KSD610, gives Pani niguro as the common name and Lauta as the Gurung name, and records April–June harvest with young shoots used as vegetables. The article says specimens were deposited at Tribhuvan University Central Herbarium; the voucher was not independently checked here. This is one regional report, not a national calendar or specimen-identification guide.

Food preparation in the sources

The PLOS discussion names D. esculentum among green plant parts mainly eaten after cooking, but supplies no recipe. PROSEA describes tender uncurling Diplazium leaves as boiled or steamed; that preparation statement is genus-level and is not tied to the Nepal collection KSD610. Neither source gives quantities, cooking time, temperature, storage or a food-safety endpoint.

Growing context

Kew describes the species as a perennial of the wet tropical biome. PROSEA places D. esculentum in open wet or swampy lowland and hill sites, often beside watercourses, usually with some shade but not in shady forest; its account gives elevations up to 1,100 m. The PLOS study area spans 1,400–4,000 m but does not report KSD610’s collection elevation, so those figures do not establish a contradictory specimen-level limit. PROSEA describes vegetative propagation from runners or rhizome pieces with buds and says planting needs wet conditions and shade during dry periods. These are handbook statements, not a Nepal home-growing protocol.

Harvest, cultivation study and limits

PROSEA says Diplazium plants may be harvested at two to three years from spores or possibly after six months from runners; the account does not make these Nepal trial results. It also reports that in parts of India, shade-dried young leaves retain better quality after rehydration than artificially dried leaves, without giving a moisture endpoint or safe storage duration. Mertz’s 1999 abstract describes a Sarawak study of D. esculentum and Stenochlaena palustris: shaded D. esculentum yield increased with fertilizer, while unshaded cultivation was described as infeasible under that study’s acid-sulphate soils and occasional dry spells. The full trial methods, rates and tables remain unavailable. No complete measured household recipe, validated preservation process, container trial or greenhouse method was established.

Research gaps

The deposited KSD610 voucher has not been independently re-examined; local names alone do not identify gathered ferns.

Mertz’s full methods and tables are gated, so treatment rates, yield figures, shade levels and trial design are unavailable.

No complete source-specific household recipe, food-process safety endpoint, storage life, mature container trial or greenhouse production method was found.

The April–June season is one Sikles Table 1 report, not a nationwide harvest calendar.

Research status

The underlying plant account received a partial source review. Its review scope is described in the original plant article.