CPC Plant Profile: Fragrant Maidenhair Fern
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Plant Profile

Fragrant Maidenhair Fern (Adiantum melanoleucum)

Photo Credit: Keith Bradley
Description
  • Global Rank: G4 - Apparently Secure
  • Legal Status: N/A
  • Family: Pteridaceae
  • State: FL
  • Nature Serve ID: 161301
  • Date Inducted in National Collection: 06/01/2017

A terrestrial, perennial, lithophytic fern with a short-creeping rhizome.  Its fronds are pinnate when young and bi-pinnate when they mature, reaching 50cm in length. The sori are borne along margins of fertile pinnules beneath false indusia which turn dark grey when mature. Spores are dark brown.  Despite its common name, this species does not produce a strong smell when fresh. However, when fronds are collected and dried (e.g. for an herbarium specimen), they emit a pleasant, sweet fragrance.  Adiantum melanoleucum is closely related to Adiantum tenerum and can be distinguished from this species by a more pendant habit and a frond that is less branched.

Participating Institutions
Updates
  • 10/11/2020
  • Climate Research

Some predictive models for sea-level rise show inundation of the occurrence in Everglades National Park within the next century.

  • 10/11/2020
  • Reintroduction

In 2015, Fairchild initiated introductions into two preserves within the species' historic range. Survivorship was very low in one preserve (<5%) and moderate in another (40-45%). Augmentations in the second preserve are planned for the near future, adapting methods to improve survival. Miami-Dade County removes encroaching invasive species in their preserves.

  • 10/11/2020
  • Reintroduction

Fairchild is in the process of reintroducing plants into suitable habitats for outplanting within it's historic range. Suitable areas include hammocks in Everglades National Park and a handful of Miami-Dade County preserves and privately owned hammocks. These efforts will help to further safeguard A.melanoleucum's status in Florida.

  • 10/11/2020
  • Propagation Research

Valerie Pence at CREW has developed in vitro spore propagation techniques. CREW and Fairchild propagate plants by spore in germination boxes. Large sporophytes are easily propagated by cutting through the short-creeping rhizome and roots with a sharp knife.

  • 10/11/2020
  • Propagation Research

Valerie Pence at CREW has developed in vitro spore propagation techniques. CREW and Fairchild propagate plants by spore in germination boxes. Large sporophytes are easily propagated by cutting through the short-creeping rhizome and roots with a sharp knife.

J. Possley
  • 01/15/2018

Off site drainage and lowering of the regional water table may also have negative effects.

  • 01/15/2018

Some predictive models for sea-level rise show inundation of the occurrence in Everglades National Park  within the next century.

J. Possley
  • 01/15/2018

Vegetation management crews could negatively impact this species with unintended damage from herbicide overspray, piling of vegetation debris, or removal of non-native overstory species that cause a sudden increase in light and decrease in humidity.  Development on the one private property in Miami is a threat.  

  • 01/15/2018

Hurricanes are a serious threat to this species, as damaging winds contribute to destruction of the canopy of the rockland hammock, leading to increased light levels and decreased moisture levels; environmental conditions in which A. melanoleucum needs in order to survive.  Major hurricanes could cause devastating mortality. 

  • 01/15/2018

Valerie Pence at CREW has developed in vitro spore propagation techniques.  CREW and Fairchild propagate plants by spore in germination boxes.  Large sporophytes are easily propagated by cutting through the short-creeping rhizome and roots with a sharp knife.  

  • 01/15/2018

A. melanoleucum has a narrow range globally and throughout its historic range. It is considered to be at high risk of extirpation from Florida given it's limited range and small populations sizes.  Fairchild is in the process of reintroducing plants into suitable habitats for outplanting within it's historic range.  Suitable areas include hammocks in Everglades National Park and a handful of Miami-Dade County preserves and privately owned hammocks. These efforts will help to further safeguard A.melanoleucum's status in Florida.
 

J. Possley
  • 01/15/2018

Fairchild conducts regular population monitoring. In 2015, Fairchild initiated introductions into two preserves within the species' historic range.  Survivorship was very low in one preserve (<5%) and moderate in another (40-45%).  Augmentations in the second preserve are planned for the near future, adapting methods to improve survival.  Miami-Dade County removes encroaching invasive species in their preserves.

  • 12/22/2017

Steps that need to be taken in order to preserve and maintain the species consist of the continued annual monitoring of all Miami-Dade populations for health and sporulation, continued biannual monitoring of the known population that exist on private property, and the continued collection of spores from both wild and ex situ plants for long-term cryogenic storage at the NCGRP.

  • 12/21/2017

Competition by both native and non-native invasive plants is a serious threat to A.melanoleucum, and include the following species in Miami-Dade County: Epipremnum pinnatum, Syngonium podophyllum, a non-native Neprolepis species, and others.
 

Nature Serve Biotics
  • 05/02/2017

Very rare in Florida (Everglades), but widespread in Caribbean and northern South America.

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Nomenclature
Taxon Adiantum melanoleucum
Authority Willd.
Family Pteridaceae
CPC Number 13549
ITIS 17310
USDA ADME
Common Names Fragrant Maidenhair Fern
Associated Scientific Names Adiantum melanoleucum
Distribution Historically, Adiantum melanoleucum was endemic to southern Florida, the Bahamas, The Greater Antilles, and the Cayman Islands(Proctor 1989).

Currently, In Florida, it maintains a very tenuous hold in Everglades National Park, but two known populations exist in Miami-Dade County preserves and a third is on private property. In total, the amount of sporophytes in Florida number approximately 280 with low annual variation.
State Rank
State State Rank
Florida S1
Habitat

A. melanoleucum is native to the rockland hammocks of south Florida at very low elevations and at low to middle elevations (10-360m) in Puerto Rico (Proctor 1989).  It is  commonly found growing on the walls of limestone sinkholes and outcroppings. It requires high humidity but full shade to thrive, an environment which hardwood forests provide.

Ecological Relationships

This plant is  threatened by natural disturbances such as fire and hurricanes. Although fire would likely cause mortality, it is not currently a significant threat to the rockland hammocks in which this plant propagates.
Hurricanes reduce the canopy cover of the hammock habitat, likely leading to increased light and moisture levels which can be fatal to A. melanoleucum. Major hurricanes could contribute to a high mortality rate of this species.

A. melanoleucum coexists with mature rockland hammock tree species in the overstory canopy (e.g.Sideroxylon foetidissimum, Ficus aurea, and Bursera simarouba) as well as other native, lithophytic ferns in the understory (e.g. Thelypteris sclerophylla, Thelypteris reptans).

Pollinators
Common Name Name in Text Association Type Source InteractionID

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