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Collomia grandiflora

California Strawflower · Grand Collomia · Large-flower Collomia

Family PolemoniaceaeGenus Collomia

A rounded head of pale pink trumpet flowers opening into five narrow lobes, above whorls of slim pointed leaves.
FlowerKeith EdkinsCC BY 2.5

About the plant

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

Habit
annualPlants of the World Online
Habit
Annual, Forb/herbPLANTS Database
Flower
White, yellow, orangeWikipedia
Native range
Canada, lower 48 statesPLANTS Database

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; PLANTS Database — USDA NRCS; Wikipedia — Wikipedia contributors.

This source reports two treatments. Both are shown.

Protocol 1

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around March 8, 2027 for a May 3 last frost.

  1. Cold moist stratification

    Temperature: 40°F 4°C

Germination happens during step 1, in 28 days.

90% germination in 14–28 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Collomia p. 32Public domain
Show the original text
Collomia (Polemoniaaceae). C. grandiflora had been studied before. A new sample germ/70D(70% in 2-14 d)-40(30%) and 40(90% in 2-4 w). This is in essential agreement with the earlier work. Two other species studied earlier require GA-3 for germination, but GA-3 caused total rotting in C. grandiflora.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Collomia p. 32. 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, 1996

Difficulty Moderate Rated by us, not by the source.

Start around March 22, 2027 for a May 3 last frost.

  1. Warm moist stratification

    Duration: 90 daysTemperature: 70°F 21°C Light: dark

  2. Cold moist stratification

    Duration: 90 daysTemperature: 40°F 4°C

    30 germinated in this phase.

Steps after step 1 run on after germination.

Germination happens during step 1, in 14 days.

70% germination in 2–14 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Collomia p. 32Public domain
Show the original text
Collomia (Polemoniaaceae). C. grandiflora had been studied before. A new sample germ/70D(70% in 2-14 d)-40(30%) and 40(90% in 2-4 w). This is in essential agreement with the earlier work. Two other species studied earlier require GA-3 for germination, but GA-3 caused total rotting in C. grandiflora.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Collomia p. 32. 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.

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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