CPC Plant Profile: Na Pali Beach Hedyotis
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Plant Profile

Na Pali Beach Hedyotis (Kadua st.-johnii)

Closeup of flowering plant. Notice the fleshy corolla. Photo Credit: D. Lorence
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Rubiaceae
  • State: HI
  • Nature Serve ID: 150369
  • Date Inducted in National Collection: 07/09/1992

Species in the genus Hedyotis are members of the coffee family (Rubiaceae). There are 17 recorded taxa of Hedyotis and, of these, 14 are threatened or endangered, and one is extinct. H. st.-johnii (Na Pali beach hedyotis) is a Federally endangered species, with only four populations containing around 200 individuals total known in the wild (USFWS 2001). Na Pali beach hedyotis is a succulent perennial herb with slightly woody, trailing, quadrangular stems. Its fleshy leaves cluster towards the base of the stem. Flower clusters are borne on 7 to 15 centimeter-long flowering stems. The green flower petals are fused into a tube about 5 to 8 millimeters long and wide. The fruits are kidney-shaped with dark brown to blackish angular seeds (USFWS 1995). This species is distinguished from related species by its succulence, basally clustered fleshy leaves, shorter floral tube, and large leafy calyx lobes when in fruit (Wagner et al. 1999).

Participating Institutions
Updates
Nature Serve Biotics
  • 05/02/2017

Endemic to the northwestern coast of the island of Kauai. This species is restricted to a narrow broken band of rocky coastline not far above sea level. Currently, fewer than 200 plants are known at 4 locations. Goats are the major cause of decline in this species, due to predation and habitat degradation. The species is now almost entirely restricted to sites inaccessible to goats. Alien weeds also represent a threat to this species. Other potential threats are landslides and fire.

  • 01/01/2010

Threats to H. st.-johnii include: herbivory and habitat degradation by feral goats competition from alien plant species, especially Pluchea carolinensis (sour bush) landslides fire trampling and grazing by cattle a risk of extinction due to na

  • 01/01/2010

Number of Populations: 4 (USFWS 2001) Number of Plants: 200 (USFWS 2001)

  • 01/01/2010

The seeds of H. st.-johnii have been tested by the National Seed Storage Laboratory (NSSL), finding that they are orthodox and can tolerate freezing and drying. The laboratory germination time was 6 months (Yoshinaga 2002).

  • 01/01/2010

The National Tropical Botanical Garden (NTBG) currently has ex situ collections of numerous seeds, representing all four populations. There are 18 individuals representing one population in the nursery, and five plants growing in the grounds of the botanical garden from an unknown locality.

  • 01/01/2010

1. Map genetic diversity in the surviving populations of H. st.-johnii. 2. Test the influence of weeding and fencing on populations of H. st.-johnii. 3. Conduct pollination biology and seed dispersal studies. 4. Establish protection and management for all extant populations. Recommendations derived from M.H. Chapin, and M. Maunder.

  • 01/01/2010

1. Establish secure ex situ stocks with full founder representation. 2. Develop proper horticultural protocols and pest management for H. st.-johnii. 3. Survey ex situ holdings and conduct molecular fingerprinting. Recommendations derived from M.H. Chapin and M. Maunder.

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Photos
Nomenclature
Taxon Kadua st.-johnii
Authority (B.C. Stone & Lane) W.L. Wagner & Lorence
Family Rubiaceae
CPC Number 6314
ITIS 846025
USDA
Common Names Na Pali Beach hedyotis | Na Pali beach starviolet | Napali Beach starviolet
Associated Scientific Names Hedyotis st.-johnii | Kadua st.-johnii (B.C. Stone & Lane)
Distribution H. st.-johnii is distributed on State owned land on the Na Pali coast of Kauai: between Kalalau and Honopu beaches, in Nualolo Valley, Nualolo Kai, at Milolii Beach, and in Polihale (USFWS 1995).
State Rank
State State Rank
Hawaii S1
Habitat

H. st.-johnii grows in the crevices of north-facing, near-vertical coastal cliff faces within the spray zone (below 75 meters) (USFWS 2000). Associated species of H. st.-johnii include Myoporum sandwicense (naio), Eragrostis variabilis (kawelu), Lycium sandwicense (ohelo kai), Heteropogon contortus (pili), Artemisia australis (ahinahina), and Chamaesyce celastroides (akoko).

Ecological Relationships

None known.

Pollinators
Common Name Name in Text Association Type Source InteractionID

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