Calystegia macrostegia subsp. amplissima
Island morning-glory, Island Morning-Glory
Photo: parent species Calystegia macrostegia · Photo by Chez Brungraber
Family: Convolvulaceae · Type: Vine · Native
Conservation status: CNPS 4.3
Calystegia macrostegia subsp. amplissima (Island morning-glory) is a native California vine in the Convolvulaceae family, recognized by on Channel Islands; key features are very large flowers and bracts.
Island morning-glory is a California native perennial found in the southern Channel Islands on rocky slopes and canyon walls at elevations generally below 100 meters. Flowering from February to July, this plant produces large white flowers with pale pink or lavender tints in delicate trumpet-shaped blooms 47 to 68 millimeters long. Growing with climbing or trailing stems that become nearly hairless with age, it spreads across rocky terrain with distinctive leaves featuring widely rounded sinuses and two to three-tipped lobes. Its leaves have a characteristically complex shape, with lobes arranged in a distinctive pattern and broad, rounded base. Large papery bracts surrounding the flower are widely ovate, 19 to 37 millimeters long, with strongly keeled or sac-like edges and rounded to pointed tips.
Identification and appearance
Key characters: 5 sympatric species on Channel Islands; key features are very large flowers and bracts
Habitat and range
Habitat: Rocky slopes, canyon walls
Elevation: generally < 100 m
California counties: Santa Barbara, Los Angeles, Ventura, San Diego
Bloom period
Calystegia macrostegia subsp. amplissima blooms Feb-Jul.
Conservation status
CNPS 4.3
How to tell it apart
vs Convolvulus: Convolvulus has smaller flowers with sharply pointed stigma lobes; Calystegia stigma lobes are blunt.; vs Ipomoea: Ipomoea stigma is a single rounded knob; Calystegia stigma has two distinct flattened lobes.; vs Datura: Datura flowers are upright with pleated edges; Calystegia flowers are smooth funnels.; vs Abronia: Abronia has clusters of small tubular flowers; Calystegia has single large funnel flowers.; vs Oenothera: Oenothera has four separate petals; Calystegia petals are fused into continuous funnel.
Frequently asked questions
Is Calystegia macrostegia subsp. amplissima native to California?
Yes. Calystegia macrostegia subsp. amplissima is native to California (recorded as native).
When does Calystegia macrostegia subsp. amplissima bloom?
Calystegia macrostegia subsp. amplissima blooms Feb-Jul.
Where in California does Calystegia macrostegia subsp. amplissima grow?
Calystegia macrostegia subsp. amplissima occurs in Santa Barbara, Los Angeles, Ventura, San Diego, at elevations of generally < 100 m.
What plant family does Calystegia macrostegia subsp. amplissima belong to?
Calystegia macrostegia subsp. amplissima is in the Convolvulaceae family, genus Calystegia.
Is Calystegia macrostegia subsp. amplissima rare or endangered?
Calystegia macrostegia subsp. amplissima carries California Rare Plant Rank 4.3, state rank S4.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.