Species Details

Holocarpha macradenia

Santa Cruz tarplant

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Photo of Holocarpha macradenia
© 2011 Dylan Neubauer
Photo of Holocarpha macradenia
© 2016 John Doyen
Photo of Holocarpha macradenia
© 2016 John B. Moule
Scientific Name:
Holocarpha macradenia (DC.) Greene
Common Name:
Santa Cruz tarplant
Family: Asteraceae
Element Code: PDAST4X020
USDA Plants Symbol: HOMA
Synonyms/Other Names:
CA Rare Plant Rank: 1B.1
Fed List: FT (2000-03-20)
State List: CE (1979-09-01)
Global Rank: G1
State Rank:
S1
Other Status: SB_CalBG/RSABG; SB_UCBG
CRPR Changes:
Add Date: 1974-01-01
Date Edited: 2022-01-05
Lifeform: annual herb
Blooming Period: Jun-Oct
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Elevation:
10 - 220 meters
35 - 720 feet
General Habitats:
  • Coastal prairie
  • Coastal scrub
  • Valley and foothill grassland
Microhabitat Details:
Microhabitat:
  • Clay (often)
  • Sandy
Notes:
All extant CCA Co. occurrences (465B, 466A) are introduced; nearly half have failed. Last remaining natural population in the S.F. Bay Area extirpated by development in 1993. Seriously threatened by urbanization, agriculture, non-native plants, and lack of appropriate ecological disturbance. See Fremontia 5(4):15-16 (1978) for species account.
Threats:
Taxonomy:
Threat List Total: 10
Total EOs % of EOs
EOs with Threat Listed: 29 78 %
THREAT LIST:
Development 19 51%
Grazing 12 32%
Non-native plant impacts 11 29%
Other 4 10%
Foot traffic/trampling 4 10%
Total Occurrences: 37
Element Occurrence Ranks:
A B C D X U
1 4 8 5 16 3
Occurrence Status:
Historical >20 Years 29
Recent <=20 Years 8
Presence:
Presumed Extant 21
Possibly Extirpated 8
Presumed Extirpated 8
California Endemic:
California Island:
States: Name (Code)
California (CA)
California Counties and Islands: Name (Code)
Alameda (ALA)*, Contra Costa (CCA)*, Marin (MRN)*, Monterey (MNT), Santa Cruz (SCR)
Quads: Name (Quad Code)
Briones Valley (3712282), Felton (3712211), Hayward (3712261)*, Laurel (3712118), Oakland West (3712273)*, Prunedale (3612176), Richmond (3712283)*, San Rafael (3712285)*, Santa Cruz (3612281), Soquel (3612188), Watsonville East (3612186), Watsonville West (3612187)
Notes:
Definitions of codes following a county and/or quad:
* Presumed extirpated
(?) Occurrence confirmed, but possibly extirpated
Quad and county data is imported from the CNDDB. Species may be present in other areas where conditions are favorable. These data should NOT be substituted for pre-project review or for on-site surveys.
Presumed Extant
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