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Omalotheca norvegica

Highland Cudweed · Norwegian Arctic Cudweed · Norwegian Cudweed

Family AsteraceaeGenus Omalotheca

A crowded spike of small brown flower heads with pale tips, set among narrow leaves covered in silvery-white felt.
FlowerJerzy OpiołaCC BY-SA 3.0

About the plant

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

Habit
perennialPlants of the World Online
Habit
Perennial, Forb/herbPLANTS Database
Flower
BrownRead from the photograph on this page
Native range
Altay, Austria, Bulgaria, Buryatiya, Czechia-Slovakia, East European Russia and elsewhereGBIF 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; PLANTS Database — USDA NRCS; Read from the photograph on this page — Deno's Garden; GBIF Backbone Taxonomy — Global Biodiversity Information Facility.

Two sources report 7 treatments between them. All are shown.

Protocol 1

DerivedN. C. Deno, 1998

Difficulty Low Rated by us, not by the source.

Start around March 23, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 22, 2025.

  1. Dry storage

    Duration: 730 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 2 years from start to sowing. Then 14 days to germinate.

100% germination in 14 days.

Seed Germination Theory and Practice, 2nd Supplement — N. C. Deno, 1998 · 2nd Supplement, Omalotheca p. 51Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica DS 2 y or 3 y germ. 70D(100% in 2nd w) the same as fresh seeds.
Seed Germination Theory and Practice, 2nd Supplement, 2nd Supplement, Omalotheca p. 51. 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 Low Rated by us, not by the source.

Start around March 15, 2027 for a May 3 last frost.

  1. Sow and cover

    Temperature: 70°F 21°C Light: light

No stated waiting before sowing. Then 21 days to germinate.

100% germination in 7–21 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Omalotheca p. 62Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica germ.'100% in 2nd w in 70D, 70L, or 70 GA-3. It also germ. 40- 70D(32%). After 1 y DS seeds germ. 70D(83% in 8-12 d). O. (Gnaphalium) supina had a light requirement, unusual in Asteraceae, and more unusual, this light requirement partially disappeared after 3 m at 40. Seeds germ. 70L(100% in 1-3 w), 70 GA-3(100% in 5-7 d), and 70D(none). When the seeds in 70D were shifted to 70L after 4 w, 100% germ. on the 4th d. Seeds also germ. 40- 70D(41% in 3-5 d). It is remarkable that an initial 3 m at 40 removed part of the light requirement, but 70L is still the best treatment. Seeds DS 1 y germ. 70D(56% in 10-20 d) showing disappearance of the light requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Omalotheca p. 62. 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 3

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around March 29, 2027 for a May 3 last frost.

  1. Gibberellic acid soak

  2. Sow and cover

    Temperature: 70°F 21°C

No stated waiting before sowing. Then 7 days to germinate.

100% germination in 5–7 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Omalotheca p. 62Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica germ.'100% in 2nd w in 70D, 70L, or 70 GA-3. It also germ. 40- 70D(32%). After 1 y DS seeds germ. 70D(83% in 8-12 d). O. (Gnaphalium) supina had a light requirement, unusual in Asteraceae, and more unusual, this light requirement partially disappeared after 3 m at 40. Seeds germ. 70L(100% in 1-3 w), 70 GA-3(100% in 5-7 d), and 70D(none). When the seeds in 70D were shifted to 70L after 4 w, 100% germ. on the 4th d. Seeds also germ. 40- 70D(41% in 3-5 d). It is remarkable that an initial 3 m at 40 removed part of the light requirement, but 70L is still the best treatment. Seeds DS 1 y germ. 70D(56% in 10-20 d) showing disappearance of the light requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Omalotheca p. 62. 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 4

DerivedN. C. Deno, 1996

Difficulty Low Rated by us, not by the source.

Start around March 25, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 24, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 12 months from start to sowing. Then 12 days to germinate.

83% germination in 8–12 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Omalotheca p. 62Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica germ.'100% in 2nd w in 70D, 70L, or 70 GA-3. It also germ. 40- 70D(32%). After 1 y DS seeds germ. 70D(83% in 8-12 d). O. (Gnaphalium) supina had a light requirement, unusual in Asteraceae, and more unusual, this light requirement partially disappeared after 3 m at 40. Seeds germ. 70L(100% in 1-3 w), 70 GA-3(100% in 5-7 d), and 70D(none). When the seeds in 70D were shifted to 70L after 4 w, 100% germ. on the 4th d. Seeds also germ. 40- 70D(41% in 3-5 d). It is remarkable that an initial 3 m at 40 removed part of the light requirement, but 70L is still the best treatment. Seeds DS 1 y germ. 70D(56% in 10-20 d) showing disappearance of the light requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Omalotheca p. 62. 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 5

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

Start around March 17, 2027 for a May 3 last frost. Too late for spring 2027 — that needed starting on March 16, 2026.

  1. Dry storage

    Duration: 365 daysTemperature: 70°F 21°C

  2. Sow and cover

    Temperature: 70°F 21°C Light: dark

about 12 months from start to sowing. Then 20 days to germinate.

56% germination in 10–20 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Omalotheca p. 62Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica germ.'100% in 2nd w in 70D, 70L, or 70 GA-3. It also germ. 40- 70D(32%). After 1 y DS seeds germ. 70D(83% in 8-12 d). O. (Gnaphalium) supina had a light requirement, unusual in Asteraceae, and more unusual, this light requirement partially disappeared after 3 m at 40. Seeds germ. 70L(100% in 1-3 w), 70 GA-3(100% in 5-7 d), and 70D(none). When the seeds in 70D were shifted to 70L after 4 w, 100% germ. on the 4th d. Seeds also germ. 40- 70D(41% in 3-5 d). It is remarkable that an initial 3 m at 40 removed part of the light requirement, but 70L is still the best treatment. Seeds DS 1 y germ. 70D(56% in 10-20 d) showing disappearance of the light requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Omalotheca p. 62. 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 6

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

Start around December 31, 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 Light: dark

about 3 months from start to step 2. Germination happens during step 2, in 5 days.

41% germination in 3–5 days.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Omalotheca p. 62Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica germ.'100% in 2nd w in 70D, 70L, or 70 GA-3. It also germ. 40- 70D(32%). After 1 y DS seeds germ. 70D(83% in 8-12 d). O. (Gnaphalium) supina had a light requirement, unusual in Asteraceae, and more unusual, this light requirement partially disappeared after 3 m at 40. Seeds germ. 70L(100% in 1-3 w), 70 GA-3(100% in 5-7 d), and 70D(none). When the seeds in 70D were shifted to 70L after 4 w, 100% germ. on the 4th d. Seeds also germ. 40- 70D(41% in 3-5 d). It is remarkable that an initial 3 m at 40 removed part of the light requirement, but 70L is still the best treatment. Seeds DS 1 y germ. 70D(56% in 10-20 d) showing disappearance of the light requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Omalotheca p. 62. 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 7

DerivedN. C. Deno, 1996

Difficulty Moderate Rated by us, not by the source.

Start around December 15, 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 Light: dark

about 3 months from start to step 2. Germination happens during step 2; time not stated, 21 days assumed.

32% germination.

Seed Germination Theory and Practice, 1st Supplement — N. C. Deno, 1996 · 1st Supplement, Omalotheca p. 62Public domain
Show the original text
Omalotheca (Asteraceae). O. norvegica germ.'100% in 2nd w in 70D, 70L, or 70 GA-3. It also germ. 40- 70D(32%). After 1 y DS seeds germ. 70D(83% in 8-12 d). O. (Gnaphalium) supina had a light requirement, unusual in Asteraceae, and more unusual, this light requirement partially disappeared after 3 m at 40. Seeds germ. 70L(100% in 1-3 w), 70 GA-3(100% in 5-7 d), and 70D(none). When the seeds in 70D were shifted to 70L after 4 w, 100% germ. on the 4th d. Seeds also germ. 40- 70D(41% in 3-5 d). It is remarkable that an initial 3 m at 40 removed part of the light requirement, but 70L is still the best treatment. Seeds DS 1 y germ. 70D(56% in 10-20 d) showing disappearance of the light requirement.
Seed Germination Theory and Practice, 1st Supplement, 1st Supplement, Omalotheca p. 62. 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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