Taxon Report

Calystegia peirsonii (Abrams) Brummitt

Peirson's morning-glory

Print Report


Taxon Summary

Calystegia peirsonii, commonly known as Peirson's morning-glory, is a perennial rhizomatous herb in the Convolvulaceae that is found only in California. It occurs within Chaparral, Chenopod scrub, Cismontane woodland, Coastal scrub, Lower montane coniferous forest, and Valley and foothill grassland, growing at elevations from 30 to 1500 meters. Calystegia peirsonii is ranked 4.2, Plants of Limited Distribution, A Watch List; Moderately threatened in California.

  Classification
Scientific Name:
 Calystegia peirsonii (Abrams) Brummitt
Common Name:
 Peirson's morning-glory
Family: Convolvulaceae
Element Code: PDCON040A0
USDA Plants Symbol: CAPE18
Synonyms/Other Names:

Ecology and Life History
Lifeform: perennial rhizomatous herb
Blooming Period: Apr-Jun Apr-Jun
Elevation: 30-1500 (100-4920)
General Habitats: Chaparral, Chenopod scrub, Cismontane woodland, Coastal scrub, Lower montane coniferous forest, Valley and foothill grassland
Microhabitat:
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 4.2
Global Rank: G4
State Rank:
 S4
State List: None
Fed List: None
Other Status:
CRPR Changes:

Occurrence Data from the CNDDB
Total Occurrences: 26
Element Occurrence Ranks:
   Excellent (A) 5
   Good (B) 14
   Fair (C) 3
   Poor (D) 0
   None (X) 0
   Unknown (U) 4

Location
California Endemic:  True
California Counties and Islands: Name (Code)
Kern (KRN), Los Angeles (LAX), Ventura (VEN)
Quads: Name (Quad Code)
Agua Dulce (3411843), Black Mtn. (3411867), Burnt Peak (3411865), Del Sur (3411863), Green Valley (3411854), Lake Hughes (3411864), Lancaster West (3411862), Lebec (3411877), Liebre Mtn. (3411866), Littlerock (3411758), Mescal Creek (3411746), Mint Canyon (3411844), Newhall (3411845), Oat Mountain (3411835), Pacifico Mountain (3411841), Palmdale (3411851), Ritter Ridge (3411852), San Fernando (3411834), Santa Paula (3411931), Santa Susana (3411836), Sleepy Valley (3411853), Torrance (3311873), Tylerhorse Canyon (3411884), Val Verde (3411846), Valyermo (3411747), Warm Springs Mountain (3411855), Whitaker Peak (3411856)

Threat List Data from the CNDDB

Threat List Total: 1
EOs with Threat Listed: Total EOs % of EOs
2 8 %
Grazing 2 7%

Notes
Threatened by grazing and development. Possibly threatened by powerline construction. Intergrades with other Calystegia spp. See Illustrated Flora of the Pacific States 3:387 (1951) by L. Abrams for original description, and Annals of the Missouri Botanical Garden 52(2):214-216 (1965) for revised nomenclature.
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 21 February 2025].