White morning glory

In brief

Calystegia occidentalis, Convolvulaceae.

- Perennial vine from a rhizome
- Native to California and Oregon
- Flowers May to July
- Fruit a small capsule

Where it grows

Chaparral and dry woodland through the Coast Ranges and the Sierra Nevada foothills, climbing over brush and litter instead of running flat along the ground.

When it blooms

May to July. Photographed here on June 3, 2023, twining through pine litter.

Seed and fruit

A small round capsule holding a few large seeds. It spreads mostly by the rhizome, which runs deep enough to come back after a fire.

Here

White with a cream throat, about four centimeters across, on a twining vine with arrowhead leaves.

The name is the problem. Morning glory in California usually means field bindweed, an introduced weed of tilled ground with a flower half this size, and this is not that. It is a native, and it belongs in the brush it is growing through.

The species is not settled. What would close it is one frame of the two bracts where the flower stalk meets the calyx: in Calystegia they sit tight against the calyx and hide it, and in the introduced Convolvulus they sit well down the stalk.