Notholaena standleyi aka Star Cloak Fern

Notholaena standleyi is considered a challenging fern to cultivate outside of its native desert habitat. It requires excellent drainage, bright direct sun, and very little water—conditions that differ sharply from those needed by most ornamental ferns. Overwatering or poor drainage is the most common cause of failure.

Notholaena standleyi is native to the desert and semi-arid regions of the southwestern United States—specifically Arizona, Colorado, New Mexico, Oklahoma, and Texas—and extends into northern and central Mexico. It grows in rocky terrain including limestone and granite boulder crevices and desert hillsides, at elevations ranging from about 300 to 2,100 meters (980–6,900 feet).

This fern naturally colonizes rocky crevices in limestone and granite, indicating a strong preference for very well-drained, lean, gritty or sandy soils. Soil pH in its native range tends toward neutral to slightly alkaline, consistent with limestone substrates. Rich or moisture-retentive soils are unsuitable and typically fatal in cultivation.

Notholaena standleyi is native to desert regions spanning elevations of 300–2,100 meters in the southwestern US and Mexico. It tolerates the temperature extremes characteristic of these habitats—hot summers and cold winters—and is considered apparently secure across its range, suggesting broad climatic tolerance. Specific USDA hardiness zone data are not widely published for this species.

As a desert specialist, Notholaena standleyi is adapted to very low humidity. High ambient humidity is not required and may actually be detrimental, promoting fungal issues in poorly drained conditions. The farina (waxy frond coating) is thought to help reduce water loss in arid environments.

In its native habitat, Notholaena standleyi sporulates from late spring through fall. During dry periods, fronds curl and brown as the plant enters dormancy; they revive once moisture returns. In cultivation, watering should be minimal and concentrated in the active growing season (spring through fall), with very little to no supplemental water in winter.

Notholaena standleyi is a fern and does not produce flowers or seeds. It reproduces via spores borne on the undersides of fronds, typically producing 32 spores per sporangium. Sporulation occurs from late spring through fall.

Four chemotypes of Notholaena standleyi are documented, differing in farina color (gold, yellow, pallid, or yellow-green) and chromosome set number, corresponding to populations across the southwestern US and Mexico. Molecular phylogenetic research (Kao et al., 2020, American Journal of Botany) further identified four infraspecific lineages based on molecular, cytological, and biochemical data.

Notholaena standleyi is best grown outdoors in climates that replicate its native southwestern US and Mexican desert habitat: full sun, dry conditions, rocky or gritty well-drained soil, and low rainfall. It is not suited for humid or poorly drained garden sites. In appropriate climates (USDA zones roughly 7–11 in arid regions), it can be grown in rock gardens or dry-wall crevices.

Notholaena standleyi is propagated from spores. The plant sporulates from late spring through fall, and germination takes approximately 13 days under appropriate conditions. Spore sowing should follow standard pteridophyte techniques: sterile medium, high humidity during germination, and gradual acclimatization to the plant's preferred dry conditions as prothalli develop.

No specific pest or disease information is documented in available sources for Notholaena standleyi. As a drought-adapted desert fern, overwatering and poor drainage—leading to root rot—are the primary cultivation risks. The farina coating on the frond undersides may offer some protection against moisture-related pathogens.

Notholaena standleyi reproduces by spores rather than by pollination. Spores are produced in sporangia on the undersides of fronds, with typically 32 spores per sporangium, and are dispersed by wind. The species is diploid (2n = 60), though four chemotypes with varying ploidy levels are documented.

The Seri people of northwest Mexico traditionally brewed a tea from Notholaena standleyi fronds, used to promote fertility in women. Contemporary laboratory research has isolated notholaenic acid from this fern, which demonstrates anti-HSV-1 (herpes simplex virus type 1) antiviral activity, albeit only at elevated concentrations. This research is preliminary and no established clinical use is recognized.

The Seri people of northwest Mexico carried Notholaena standleyi in cloth bags as a good luck charm. No other documented non-medicinal uses are reported in available sources.

No edible uses of Notholaena standleyi are documented in available sources. The plant is a desert fern with no record of food use in ethnobotanical literature consulted.

Star Cloak Fern grows vertically and new growth emerges from the top of the plant.

Star Cloak Fern should be watered regularly, allowing the soil to dry out between waterings.

To ensure optimal growth, the Star Cloak Fern prefers bright indirect light for 6-8 hours each day. Insufficient light can result in slow growth and leaf drop, so it's important to find a well-lit location for this plant. Place it near a window, within a distance of 1 meter (3 feet), to enhance its potential for thriving.

No verified data on the toxicity of this plant exists within Ploi's records. Should you, someone in your family, or your pet ingest plant material with an unknown toxicity level, it is recommended to seek medical advice.