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Caltha biflora

Howell's Marigold · Two-flower Marsh-marigold · Broad-leaved Marsh Marigold

Family RanunculaceaeGenus Caltha

Glossy heart-shaped leaves spreading over wet mossy ground, with one white flower and a single bud on short stalks.
The whole plantAllan HarrisCC0

About the plant

What it is and where it grows — not part of any germination protocol.

Habit
perennialPlants of the World Online
Flower
WhiteRead from the photograph on this page
Native range
Alaska, British Columbia, California, Nevada, Oregon, WashingtonGBIF Backbone Taxonomy

Toxicity is noted only where a source states it. No note here is not a finding of safety.

Sources: Plants of the World Online — Royal Botanic Gardens, Kew; Read from the photograph on this page — Deno's Garden; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1993

Difficulty High Rated by us, not by the source.

Start around November 17, 2026 for a May 3 last frost.

  1. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

  2. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C

about 3 months from start to step 2. Germination happens during step 2, in 49 days.

12% germination in 49 days.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Caltha p. 110Public domain
Show the original text
Caltha (Ranunculaceae). C. biflora germ. 40-70(1/8 in 7th w) and none in 70-40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Caltha p. 110. Quoted exactly. Every value on this card comes from this record, except the difficulty rating, which is ours; the step names come from a fixed list.

Protocol 2

DerivedN. C. Deno, 1993

  1. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing.

0% germination.

Nothing germinated at 70.

Seed Germination Theory and Practice, 2nd ed. — N. C. Deno, 1993 · Ch. 20, Caltha p. 110Public domain
Show the original text
Caltha (Ranunculaceae). C. biflora germ. 40-70(1/8 in 7th w) and none in 70-40.
Seed Germination Theory and Practice, 2nd ed., Ch. 20, Caltha p. 110. Quoted exactly. Every value on this card comes from this record; the step names come from a fixed list.

How each step is done, in Deno’s words, and what Verified and Derived mean.

Germination trials

Readers’ own records of sowing this species, published after review. Share your trial · All trials

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