Taxon Report

Nemacaulis denudata Nutt. var. gracilis Goodm. & Benson

slender cottonheads

Print Report


Taxon Summary

Nemacaulis denudata var. gracilis, commonly known as slender cottonheads, is a annual herb in the Polygonaceae that is found in California and elsewhere. It occurs within Coastal dunes, Desert dunes, and Sonoran desert scrub, growing at elevations from -50 to 400 meters. Nemacaulis denudata var. gracilis is ranked 2B.2, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Moderately threatened in California.

  Classification
Scientific Name:
 Nemacaulis denudata Nutt. var. gracilis Goodm. & Benson
Common Name:
 slender cottonheads
Family: Polygonaceae
Element Code: PDPGN0G012
USDA Plants Symbol: NEDEG
Synonyms/Other Names:

Ecology and Life History
Lifeform: annual herb
Blooming Period: (Mar)Apr-May (Mar)Apr-May
Elevation: -50-400 (-165-1310)
General Habitats: Coastal dunes, Desert dunes, Sonoran desert scrub
Microhabitat:
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 2B.2
Global Rank: G3G4T3?
State Rank:
 S2
State List: None
Fed List: None
Other Status:
CRPR Changes:
  • changed from 2.2 to 2B.2 on 2013-06-12

Occurrence Data from the CNDDB
Total Occurrences: 24
Element Occurrence Ranks:
   Excellent (A) 1
   Good (B) 1
   Fair (C) 0
   Poor (D) 0
   None (X) 6
   Unknown (U) 16

Location
California Endemic:  False
California Counties and Islands: Name (Code)
Imperial (IMP), Riverside (RIV), San Bernardino (SBD), San Diego (SDG)
Quads: Name (Quad Code)
Acolita (3311512), Amos (3311513), Arica Mountains (3411418), Budweiser Wash (3411577), Cactus (3211478), Carrizo Mtn. (3211671), Cathedral City (3311674), Clarks Pass (3411515), Clyde (3211488), Cowhole Mountain (3511518), Coyote Wells (3211568), Desert Hot Springs (3311685), East of Acolita (3311511), Gene Wash (3411432), Glamis (3211581), Glamis NW (3211582), Glamis SE (3211571), Glasgow (3411587), Imperial Beach (3211751), In-ko-pah Gorge (3211661), Kelso Dunes (3411586), La Quinta (3311663), Mecca (3311651), Oceanside (3311724), Old Dad Mtn. (3511517), Painted Gorge (3211578), Palm Springs (3311675), Point Loma (3211762), Rice (3411417), San Luis Rey (3311723), Tortuga (3311523), White Water (3311686)

Threat List Data from the CNDDB

Threat List Total: 4
EOs with Threat Listed: Total EOs % of EOs
6 25 %
ORV activity 4 16%
Non-native plant impacts 2 8%
Development 2 8%
Grazing 1 4%

Notes
Threatened by urbanization near Palm Springs (RIV Co.) and along coast. Intergrades with var. denudata at some coastal localities. See Aliso 4:89 (1958) for original description, and Madroño 27(2):101-109 (1980) and Phytologia 66(4):390-91 (1989) for taxonomic treatments.
Threats:
Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 25 October 2025].